UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-K

(Mark One)

For the fiscal year ended December 31, 2021

OR

Commission File Number 001-39941

Sana Biotechnology, Inc.

(Exact name of Registrant as specified in its Charter)

Registrant’s telephone number, including area code: (206) 701-7914

Securities registered pursuant to Section 12(b) of the Act:

Securities registered pursuant to Section 12(g) of the Act: None

Indicate by check mark if the Registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. Yes ☒ No ☐

Indicate by check mark if the Registrant is not required to file reports pursuant to Section 13 or 15(d) of the Act. Yes ☐ No ☒

Indicate by check mark whether the Registrant: (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the Registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes ☒ No ☐

Indicate by check mark whether the Registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the Registrant was required to submit such files). Yes ☒ No ☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Indicate by check mark whether the registrant has filed a report on and attestation to its management’s assessment of the effectiveness of its internal control over financial reporting under Section 404(b) of the Sarbanes-Oxley Act (15 U.S.C. 7262(b)) by the registered public accounting firm that prepared or issued its audit report. ☐

Indicate by check mark whether the Registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act). Yes ☐ No ☒

The aggregate market value of the voting and non-voting common equity held by non-affiliates of the Registrant was approximately $3.7 billion, based on the closing price of the Registrant’s common stock on The Nasdaq Global Select Market LLC on June 30, 2021, the last business day of the Registrant’s most recently completed second fiscal quarter. Shares of the Registrant’s common stock held by each officer and director and stockholders that the Registrant has concluded are affiliates of the registrant have been excluded in that such persons may be deemed affiliates of the Registrant. This determination of affiliate status is not a determination for other purposes.

The number of shares of Registrant’s common stock outstanding as of March 11, 2022 was 189,543,388.

Table of Contents

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SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS

This Annual Report on Form 10-K (Annual Report) contains forward-looking statements that involve substantial risks and uncertainties. All statements other than statements of historical facts contained in this Annual Report could be deemed forward-looking statements, including those statements highlighted below. In some cases, you can identify these statements by forward-looking words such as “aim,” “anticipate,” “believe,” “continue,” “could,” “estimate,” “expect,” “intend,” “may,” “might,” “plan,” “potential,” “predict,” “should,” “would,” or “will,” the negative of these terms, and other comparable terminology. These forward-looking statements, which are subject to risks, include, but are not limited to, statements about:

We have based these forward-looking statements largely on our current expectations, estimates, forecasts, and projections about future events and financial trends that we believe may affect our financial condition, results of operations, business strategy, and financial needs. In light of the significant uncertainties in these forward-looking statements, you should not rely upon forward-looking statements as predictions of future events. Although we believe that we have a reasonable basis for each forward-looking statement contained in this Annual Report, we cannot guarantee that the future results, levels of activity, performance, or events and circumstances reflected in the forward-looking statements will be achieved or occur at all. You should refer to the sections titled “Risk Factors” and “Management’s Discussion and Analysis of Financial Condition and Results of Operations” for a discussion

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of important factors that may cause our actual results to differ materially from those expressed or implied by our forward-looking statements. Other sections of this Annual Report may include additional factors that could harm our business and financial performance. New risk factors emerge from time to time, and it is not possible for our management to predict all risk factors, nor can we assess the impact of all factors on our business or the extent to which any factor, or combination of factors, may cause actual results to differ materially from those contained in, or implied by, any forward-looking statements. Except as required by law, we undertake no obligation to publicly update any forward-looking statements, whether as a result of new information, future events, or otherwise.

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RISK FACTOR SUMMARY

Investing in our securities involves a high degree of risk. Below is a summary of material factors that make an investment in our securities speculative or risky. Importantly, this summary does not address all of the risks that we face. Additional discussion of the risks summarized in this Risk Factor Summary, as well as other risks that we face, can be found under the heading “Risk Factors” in Part I of this Annual Report.

Our business is subject to a number of risks of which you should be aware before making a decision to invest in our common stock. These risks include, among others, the following:

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PART I

Item 1. Business.

Overview

We were founded on the belief that engineered cells will be one of the most important transformations in medicine over the next several decades. The burden of diseases that can be addressed at their root cause through engineered cells is significant. We view engineered cells as having the potential to be as therapeutically disruptive as biologics to clinical practice. Our long-term aspirations are to be able to control or modify any gene in the body, to replace any cell that is damaged or missing, and to markedly improve access to cellular and gene-based medicines. We have brought together an experienced group of scientists, engineers, and company builders and combined them with the necessary technologies to move this vision forward. We are developing ex vivo and in vivo cell engineering platforms to revolutionize treatment across a broad array of therapeutic areas with unmet treatment needs, including oncology, diabetes, central nervous system (CNS) disorders, cardiovascular diseases, and genetic disorders, among others. Our platform progress, broad capabilities, and strong balance sheet enable us to execute on a broad vision, with a goal of submitting our first INDs in 2022, with the opportunity to submit multiple INDs per year beyond 2022.

We believe the time is right to develop engineered cell therapies across a broad range of therapeutic areas. The field has seen initial clinical proof of concept for gene and cell replacement approaches across multiple diseases, including cancer and certain genetic disorders, through the application of adeno-associated virus (AAV) based gene therapies, autologous CAR T cell therapies, and autologous and allogeneic grafts/transplants. While such existing approaches have limitations, they provide evidence that a broad range of ex vivo and in vivo engineered cells can have transformative clinical potential in at least a subset of patients. Substantial progress in the understanding of genetics, gene editing, gene control, protein engineering, stem cell biology, immunology, process analytics, and computational biology have converged to create an opportunity to markedly increase the breadth and depth of the potential impact of genetic and cellular medicines.

We are seeking to overcome these existing limitations of gene and cell therapy through our ex vivo and in vivo cell engineering platforms, both of which may facilitate the development of therapies that can transform the lives of patients by repairing cells in the body when possible and replacing them when needed. For ex vivo therapies, where diseased cells are damaged or missing entirely and an effective therapy needs to replace the entire cell, a successful therapeutic requires large-scale manufacturing of cells that engraft, function, and persist in the body. Of these, we view persistence as the greatest limitation to dramatically expanding the impact of this class of therapeutics. We believe that product candidates developed with our ex vivo cell engineering platform, which utilizes hypoimmune allogeneic cells that can “hide” from the patient’s immune system, can address this fundamental limitation and unlock a wave of disruptive therapeutics. For in vivo therapies, where the desire is to repair and control genes in the body, a successful product candidate requires both gene modification and in vivo delivery of the therapeutic payload. Of these, we view effective in vivo delivery as the greatest limitation to dramatically expanding the impact of this class of therapeutics. To this end, our initial focus is on cell-specific delivery as well as increasing the diversity and size of payloads.

We believe we have the potential to develop transformative engineered cells as medicines because of our people and our capabilities:

Our people are the most important strength of the company. We have assembled a diverse group of experienced company builders, scientists, manufacturing scientists, engineers, and operators to execute our business plan.

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Our capabilities enable us to take a comprehensive approach to the most important and difficult aspects of engineering cells. We are pursuing ex vivo and in vivo cell engineering and can leverage the synergistic proficiencies required to succeed in both approaches. We believe we can capitalize on the shared expertise and infrastructure between the platforms to maximize the potential success and the reach of our transformative therapies. We have built deep internal capabilities across a wide range of areas focused on solving the most critical limitations in engineering cells including:

Our ex vivo and in vivo Cell Engineering Platforms

The advent of recombinant DNA technology in the 1970s ushered in a new era of therapeutics, enabling the synthetic manufacture of human protein therapies at scale for the first time. However, the critical inflection point occurred when key technological advancements eventually enabled the broad development of monoclonal antibodies with suitable therapeutic properties. These advancements, combined with progress in understanding disease biology, allowed biologics to become the second largest therapeutic class. We believe engineered cells are at a similar inflection point, with key recent technological advancements providing the potential for the broad applicability of this therapeutic class.

Ex vivo cell engineering

Engineering cells ex vivo requires the ability to engineer and manufacture cells at scale and then deliver them to the patient, so that they engraft, function appropriately, and have the necessary persistence in the body. Our goal for ex vivo cell engineering is to replace any cell in the body with cells that engraft, function, and persist over time, and to manufacture those cells cost-effectively at scale. Our ex vivo cell engineering platform utilizes our hypoimmune technology to create cells that can “hide” from the patient’s immune system to enable persistence of allogeneic cells. We are striving to make therapies utilizing pluripotent stem cells with our hypoimmune genetic modifications as the starting material, which we then differentiate into a specific cell type, such as a pancreatic beta cell, before treating the patient. Additionally, for cell types for which effective differentiation protocols from a stem cell have not yet been developed, such as T cells, instead of starting from a pluripotent stem cell, we can utilize a fully differentiated allogeneic cell,

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sourced from a donor, as the starting material to which we then apply our hypoimmune genetic modifications. Our goal is to manufacture genetically modified cells that are capable of both replacing the missing cell and evading the patient’s immune system. We are now applying our technologies to make cell products for the treatment of multiple diseases.

In vivo cell engineering

Engineering cells in vivo requires the development of both an appropriate delivery vector as well as a payload to effectively modify the cell. Our goal for in vivo cell engineering is to repair and control the genes of any cell in the body. The ultimate aim is to achieve the delivery of any payload, to any cell, in a specific and repeatable way. Our in vivo cell engineering platform harnesses fusogen technology, which targets cell surface receptors, and thereby can enable cell specific delivery for a meaningful number of different cell types. Using our fusogen technology, we have shown in preclinical studies that we can specifically target numerous cell surface receptors that, when combined with delivery vehicles to form fusosomes, allow cell-specific delivery across multiple different cell types.

Our Portfolio Strategy

We believe the potential applications of our platforms are vast. To prioritize programs for our ex vivo and in vivo engineering pipeline we have used the following strategies:

Our Pipeline

We are developing a broad pipeline of product candidates focused on creating transformative ex vivo and in vivo engineered cell therapies across a range of therapeutic areas. We are in the early stages of development across a broad pipeline of product candidates, all of which are currently in the preclinical stage of development and are summarized below:

Each of our initial programs provides the potential for meaningful standalone value while also supporting our potential ability to further exploit our platforms into broadly applicable medicines.

Our most advanced hypoimmune product candidate is SC291, a CD19-directed allogeneic CAR T program for NHL, CLL, and ALL. This program is designed to address the major limitation of existing allogenic CAR T cell therapies: evasion of host versus

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graft responses (HvGR), which occurs when a patient’s immune system kills the transplanted T cells, limiting the potential benefit of the therapy. One approach to avoid HvGR has been to effectively eliminate a patient’s immune system for a short period using chemotherapy, which puts the patient at risk for severe infections. Further, the patient’s immune system will inevitably recover, which will lead to the immune system eliminating the CAR T cells, limiting the effectiveness of the therapy. Our hypoimmune technology is designed to hide cells from the patient’s immune system, giving our allogeneic CAR T cell program the potential to create medicines that persist longer in patients and avoid the risks associated with higher doses of chemotherapy. Our goal is to submit an IND for SC291 in 2022, and initial clinical success would unlock meaningful standalone value in the development of SC291 in NHL/CLL/ALL which has the potential to address scalability challenges of autologous therapies. Additionally, this initial clinical success would support and validate the expansion of our allogenic CAR T efforts, which include a CD22-targeting allogeneic CAR T which could be combined with targeting CD19 (SC276) and offers the potential benefit of higher and more durable complete response rates, and a BCMA directed CAR T (SC255) in multiple myeloma. Furthermore, initial clinical success would also support the validation of the hypoimmune platform overall, which is being actively deployed internally across a number of other therapeutic areas beyond oncology.

Our next most advanced hypoimmune product candidate is SC451, PSC-derived pancreatic beta cells for the treatment of diabetes, with an initial focus on Type I diabetes mellitus (T1DM). Almost 1.6 million people in the United States, and 2.4 million in Europe have T1DM. T1DM is a disease in which a patient’s immune system attacks and kills pancreatic beta cells, leading to complete loss of insulin production in affected individuals. Patients need to take multiple insulin injections every day for life, and, while insulin has a profoundly positive impact on patients, people with T1DM have approximately 15 years shorter life expectancies than people without diabetes and are consistently at risk for complications such as coma, stroke, myocardial infarction, kidney failure, and blindness from poorly controlled blood glucose. We and our collaborators have shown that we can develop high quality beta cells that, when transplanted, normalize blood glucose and cure diabetes in animal models. We have also shown that our hypoimmune cells induce no systemic immune response, even in NHPs with a pre-existing immune response to non-hypoimmune cells. As a result, we believe our stem cell derived hypoimmune pancreatic cells have the potential to create a disruptive treatment for T1DM, offering patients life-long normal blood glucose without immunosuppression. We are working through the process development and IND-enabling studies to allow for an IND submission for SC451 as early as 2023.

Our most advanced fusosome product candidate is SG295, which targets CD19+ cancer cells, including NHL, CLL, and ALL. This program provides us with an opportunity to develop potential product candidates to expand access to CAR T cell therapy to many more patients in need. In addition, we believe the ability to deliver a payload encoding a CAR to a T cell without meaningful ex vivo manipulation has the potential to improve effectiveness over ex vivo manufactured CAR T cell products. These approaches should result in the generation of therapeutically active CAR T cells without the complexities and delays associated with the process of T cell collection and ex vivo manufacturing. Furthermore, the ex vivo expansion in the presence of high cytokine concentrations, while necessary for the manufacture of approved CAR T cell products, also contributes to marked changes in T cell quality that may not be therapeutically beneficial. The generation of a CAR T cell within the natural physiological environment in vivo has the potential to improve the quality of the CAR T cell generated, potentially improving both efficacy and the side effect profile. Finally, the effectiveness of ex vivo manufactured CAR T cells is dependent on the administration of a lymphodepleting preparative regimen prior to infusion to facilitate expansion of the CAR T cell product, which can have meaningful adverse safety implications. We do not expect to need a lymphodepleting regimen prior to in vivo delivery of the CAR gene, as our goal is to expose our fusosomes to as many T cells in the body as possible. Our goal is to submit an IND for SG295 in 2022 and initial clinical success would unlock meaningful standalone value in the development of SG295 in NHL/CLL/ALL Additionally, this initial clinical success would support and validate the expansion of our in vivo CAR T efforts and support the validation of our fusosome platform overall, which is being actively deployed internally across a number of other therapeutic areas beyond oncology with the goal of targeted delivery of DNA and gene editing machinery to specific cells in vivo.

Our ex vivo Cell Engineering Platform

Overview

Ex vivo cell engineering aims to treat human disease by engrafting new cells to replace diseased cells that are damaged or missing in patients. Historically there have been four key challenges to ex vivo cell engineering:

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Our ex vivo cell engineering platform seeks to address these four challenges and is focused on engineering hypoimmune cells that engraft, function, and persist in patients by evading immune rejection. These are derived from cell sources that are scalable and we believe that continued progress with this platform has the potential to create broad access for patients.

Our Approach to Building our ex vivo Cell Engineering Platform

We have approached the development of our ex vivo cell engineering platform by investing in solutions to address the key challenges outlined above:

Our Approach to Building our ex vivo Cell Engineering Portfolio

We have prioritized cell types for our programs where:

Based on this prioritization, we are initially focused on four cell types: T Cells, Beta cells, GPCs, and Cardiomyocytes.

Historical context of ex vivo therapy

Blood transfusions have been a standard treatment for many patients for over 100 years. The first successful kidney transplant occurred in 1954, followed by the first successful heart transplant in 1967, demonstrating the transformative clinical potential of replacing damaged or missing cells in the body. Surgical enhancements have improved the success of engraftment, but lack of organ access, a complex surgical procedure, and immune rejection of the donated organs have limited the impact of these procedures.

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Progress in immunosuppressive regimens, such as the development of cyclosporine, has improved organ survival rates. However, substantial side effects and the fact that many patients are ineligible or non-compliant have reduced their impact.

Ultimately, the field has looked for a scalable source of therapeutic cells that can be accessed broadly at a manageable cost, as well as cells that can evade immune rejection without immunosuppression. The advent of stem cell technology and subsequent improvements in methods to generate functional differentiated cells at scale have the potential to address the shortage of donor tissues and organs. In addition, over the past decade a deeper understanding of the immunology of host versus graft responses, coupled with novel techniques to manipulate the immunological profile of cells via gene editing, have raised the prospect that ex vivo engineered cells can significantly benefit patients without the requirement for significant immunosuppression.

Sources of allogeneic cells

There are three main potential sources of allogeneic cells, or cells that do not originate from the patient, and therefore have the potential to be manufactured and supplied at scale. These are embryonic stem cells (ESCs), iPSCs, and donor-derived cells. Our portfolio currently reflects a mix of sources, with the ambition of transitioning primarily to iPSCs over time.

Embryonic Stem Cells

The recognition that every cell in the body originates from a zygote, or fertilized egg, led to the research and ultimate discovery of human ESCs, with the derivation of the first human ESC line in 1998. ESCs are pluripotent stem cells which can potentially differentiate into any cell type and are derived from the inner cell mass of a blastocyst or pre-implantation stage embryo. They are typically cultured in vitro and grown through cycles of cell division, known as passages, until a line of cells is established that can proliferate without differentiating, and retain their pluripotency while remaining well characterized, including free from potentially deleterious genetic mutations. Because pluripotent stem cells can divide indefinitely without exhaustion, an ESC line can be used to generate cell banks, consisting of large numbers of well-characterized vials of cells, that can be frozen and stored for future use.

Induced Pluripotent Stem Cells

The discovery that mature, differentiated cells can be reprogrammed to be the equivalent of an ESC and capable of generating any cell type in the body, has led to the research and ultimate development of human iPSCs, providing an alternative option as a source of stem cells for use in ex vivo engineered cells. A key scientific step was the breakthrough in 2006 demonstrating that mature cells could be reprogrammed via the expression of a small number of genes to result in pluripotent cells These iPSCs have similar potential to ESCs to be used as an indefinitely renewable cell bank for manufacturing of cell-based therapies.

Donor-Derived Allogeneic Cells

Another source of cells, which we utilize in our T cell program, comes from mature donor-derived allogeneic cells. While these cells are neither pluripotent nor from an infinitely renewable source, T cells can be obtained as mature cells from human donors at scale. The use of donor-derived cells for our T cell program should allow us to rapidly advance the program towards the clinic with the implementation of our hypoimmune technology.

Approach to Sources of Allogeneic Cells

We are focused on iPSCs as the starting material for our programs, which offers regulatory and cultural advantages to ESCs, and scale and product consistency advantages to donor-derived allogeneic cells. Our portfolio currently reflects a mix of sources, which is primarily driven by historical factors as well as current better characterization of genomic stability through differentiation. Our ambition is to transition primarily to iPSCs over time.

Crucial aspects of developing allogeneic cells from any source include the thorough characterization of the cells, a comprehensive understanding of the global regulatory environment, and an ability to maintain cells under the required conditions, such as current GMP (cGMP), at various stages of the manufacturing processes. We believe our early investment in building capabilities in the science and manufacturing of these cells will increase our likelihood of success. This investment is anticipated to

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yield sources of cells suitable for the global clinical development and commercialization of ex vivo engineered cells for a broad patient population, in line with our vision to democratize access.

Background on Immunological Barriers to ex vivo Therapies and Current Limitations

Starting with studies in renal transplantation in the early 1900s, it became clear that there were immunological factors preventing successful transplantation. Initially, it was suspected to be mediated by an antibody response, but in the 1950s it was discovered that cell-mediated immune pathways also play a critical role in transplant rejection.

Further studies established T cells as playing a key role in the host immune response to transplant. T cells belong to the “adaptive” immune system, recognizing and eliminating “non-self” cells via recognition of differences in cell-surface proteins encoded by the major histocompatibility (MHC) locus. There are two types of MHC molecules: MHC class I, expressed on the surface of almost all nucleated cells, and MHC class II, expressed constitutively on professional antigen presenting cells (APC), including macrophages and dendritic cells. Expression of MHC class II is also induced in many additional cells in the context of inflammation. MHC class I molecules typically display peptides on the cell surface from degraded intracellular proteins. Cells display peptides from normal “self” proteins on MHC class I, which typically will not activate an immune response due to a process called tolerance, where the body recognizes these peptides as “self”. However, if a cell displays a peptide from a foreign or mutated protein on MHC class I, for example as a result of a protein mutation, it may result in the activation of a cytotoxic T cell response specific to the peptide-MHC complex via the T cell receptor (TCR) on the T cell surface. The activated T cell then eliminates the cell. MHC class II molecules typically display peptides derived from phagocytosis of extracellular proteins on the surface of APCs. These peptide-MHC complexes interact with TCRs on helper T cells, such as CD4+ T cells, resulting in a downstream cellular and humoral immune response. The humoral immune response leads to antibody production against foreign proteins. In allogeneic transplants, the cellular and humoral processes can recognize proteins from the donor as “foreign”, resulting in an immune response to the transplant including potential elimination of the transplanted cells. In the allogeneic setting, MHC proteins can be highly immunogenic due to their inherent polymorphism, increasing the risk of the recognition of transplants as “foreign”. This underlies the basis for MHC typing and matching to assess and reduce the risk of organ transplant rejection.

Many groups have attempted to engineer cells that can evade the adaptive immune system, typically by downregulating or eliminating expression of MHC molecules on the surface of cells. While this can reduce the adaptive immune response to donor cells, the human immune system has evolved so that parts of the innate immune system will recognize cells missing MHC molecules and eliminate them. For example, natural killer (NK) cells express receptors known as inhibitory killer-cell immunoglobulin-like receptors (inhibitory KIRs). KIRs recognize self MHC class I molecules on the surface of cells and provide inhibitory signals to the NK cells to prevent their activation. Cells missing MHC class I molecules are correspondingly eliminated by NK cells because of the lack of inhibitory KIR signaling and a resulting cytolytic activation. Known as the “missing self-hypothesis,” this important redundancy in immunology enables the elimination of virally infected or transformed cells that have downregulated MHC class I, but also has complicated the development of allogeneic cells as broadly applicable therapeutics. Our hypoimmune technology seeks to engineer cells to avoid immune rejection by addressing both the adaptive and innate immune response.

There are three key strategies that have been utilized to date to overcome immune rejection, with limited success:

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Our Solution – Hypoimmune Technology

To address the challenge of immune rejection with allogeneic cell transplantation, we are developing our hypoimmune technology, utilizing gene modification to introduce permanent changes to the cells. We are applying the hypoimmune technology to both iPSCs, which can then be differentiated into multiple cell types, and to donor-derived allogeneic T cells, which has the goal of making potent CAR T cells at scale. Our goal with this technology is to transplant allogeneic cells into patients without the need for systemic immune suppression. We believe that enabling this capability has the potential to enable ex vivo engineered cells to become an important therapeutic modality alongside small molecules, protein biologics, and in vivo engineered cells.

Some of our scientific founders, including Dr. Sonja Schrepfer, our Senior Vice President, Head of Hypoimmune Platform, and their collaborators have worked on creating hypoimmune cells for well over a decade. A key insight was focusing on the phenomenon of fetomaternal tolerance during pregnancy. The fetus, despite having half its genetic material from the father, is not rejected by the mother’s immune system. However, after birth, few if any children would qualify as a matched donor for a cell or organ transplant for their mother. These scientists categorized the differences of the maternal-fetal border and systematically tested them to understand which, if any, of these were most important to immune evasion. They have tested these changes in both in vitro and in vivo animal models.

Designing Hypoimmune Cells

Our goal is to create a universal cell that is able to evade immune detection, regardless of cell type or transplant location. Our first-generation technology, which is progressing through late-stage animal confirmatory studies, combines the three gene modifications below to hide these cells from the host immune system:

Preclinical Development of Hypoimmune Cells

We and our licensors have carried out a series of experiments in various model systems of increasing immunological complexity. These included (i) transplanting undifferentiated mouse hypoimmune iPSCs- into MHC mismatched allogeneic mice, (ii) transplanting mouse hypoimmune iPSC-derived differentiated cells, such as endothelial cells, into MHC mismatched allogeneic mice, (iii) transplanting human hypoimmune iPSCs into MHC mismatched humanized allogeneic mice; and (iv) transplanting human hypoimmune iPSCs into non-human primates (NHPs). We are currently carrying out experiments transplanting NHP hypoimmune iPSC cells into NHPs as well as transplanting NHP hypoimmune iPSC-derived differentiated cells, such as cardiomyocytes, into allogeneic NHPs.

Each mouse experiment evaluated:

We are investigating both human iPSCs in NHPs as well as NHP iPSCs in NHPs, as we want insights into how the NHP immune system reacts to each of these species. We have largely completed the study of human iPSCs and have early results from the NHP hypoimmune iPSC transplantation experiments. We are encouraged by data to date across species, with the NHP immune system most closely resembling the human immune system, representing the strictest test outside of testing these cells in humans. We are evaluating both iPSCs as well as differentiated cells transplanted into the microenvironment we intend to target in humans. Based on the results of these NHP studies, we expect to test these hypoimmune cells in humans as a next step.

Mouse iPSC-derived hypoimmune cells transplanted into MHC mismatched allogeneic mouse

Mouse hypoimmune iPSCs transplanted into an MHC mismatched allogeneic mouse were protected from the mouse immune system, and no evidence was seen of either adaptive or innate immune system activation. The control arm transplanted non-edited mouse iPSCs into MHC mismatched allogeneic mice, and, as expected, these non-edited mouse iPSCs were rapidly rejected by the recipient’s immune system with a robust adaptive immune response. In another experiment, the genes that code for MHC class I and MHC class II expression were knocked out. These modifications protected the cells from the recipient mouse’s adaptive immune

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system, but NK cells rapidly killed the transplanted cells. These data highlight the importance of making all three gene modifications in order to protect cells from the immune system with an allogeneic transplant.

Next, to ensure that hypoimmune gene modifications protected differentiated cells and that these modifications did not impact the ability of iPSCs to differentiate into various cell types, commonly referred to as pluripotency, it was tested whether the hypoimmune iPSCs cells could be differentiate into three different cell types, function in vivo, and evade the host immune system. The three cell types were cardiomyocytes, endothelial cells, and smooth muscle cells. It was observed that hypoimmune iPSCs could successfully differentiate into all three cell types, the cells functioned in the mouse, and the transplanted cells survived for the full standard observation period with no evidence of immune system activations despite any immune suppression. Differentiated cells derived from non-edited iPSC cells led to immune activation in the host mouse, and they did not survive. These data provide initial proof of concept that iPSCs can be genetically modified, and differentiated into target cells that can engraft, function, and evade the recipient’s immune system following transportation.

Human iPSC-derived hypoimmune cells transplanted into MHC mismatched allogeneic humanized mouse

Having demonstrated the ability of mouse iPSC-derived hypoimmune cells to satisfy each of three testing criteria, the experiments were advanced to evaluate human hypoimmune cells. This was evaluated using a “humanized” mouse system, generated by grafting a functioning human immune system in place of the mouse immune system.

In addition to evaluating the three primary criteria, the ability to successfully engineer human hypoimmune cells from human iPSCs and whether differentiated cells derived from human hypoimmune cells retain biological function were also evaluated.

Creating Hypoimmune Therapeutic Cells from Human iPSCs

Our hypoimmune technology combines the following three gene modifications to hide cells from the host immune system: Disruption of MHC class I and class II expression (which inactivates adaptive immune responses), and overexpression of CD47 (which hides cells from the innate immune system, including macrophages and natural killer (NK) cells). Pluripotent stem cells from healthy donors are used as the starting material and are then genetically modified with the hypoimmune edits. These edited cells are then differentiated into cell types of therapeutic interest, which are administered to the patient as “off the shelf” therapies.

First, the foregoing three edits were replicated in human iPSCs to engineer a human hypoimmune cell line that had comparable properties to the mouse hypoimmune cells in vitro. Next, non-edited human iPSCs were transplanted into MHC mismatched humanized mice. It was observed that these non-edited human iPSCs were rapidly rejected. Human hypoimmune cells were then transplanted into MHC mismatched humanized mice. It was observed that the human hypoimmune cells survived the full length of the experiment and failed to elicit any type of immune response. From this, it was concluded that, in humanized mice, the human

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hypoimmune cells can evade the immune system. Pluripotency of human hypoimmune cells was confirmed by differentiation into two different cell types, endothelial cells and cardiomyocytes. These differentiated cells exhibited the characteristics of normal endothelial cells and cardiomyocytes. Finally, to test whether these the differentiated cell types derived from human hypoimmune cells continue to evade the immune system, the differentiated cells were transplanted into humanized mice, and the transplanted cells survived for the full standard observation period. In contrast, differentiated cells derived from non-edited human iPSC cells did not survive after being transplanted, as anticipated. It was also observed that the hypoimmune endothelial cells formed primitive vasculature with active blood flow and the hypoimmune cardiomyocyte cells matured into functional-looking heart cells.

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Absence of T and B Cell Activation Following Transplantation of Hypoimmune-Edited Human iPSCs into Mismatched Humanized Mice

Left panels: T cell activation was measured by EliSpot counts for interferon-gamma production. Immune cells from mice that received wild type (wt) iPSC grafts show a brisk interferon response when tested against allogeneic wt iPSC grafts. In contrast, immune cells from mice that received hypoimmune-edited (MHC class I/II disruption, CD47 tg) cells show only minimal interferon production when exposed to allogeneic hypoimmune cells, comparable to background frequency in non-immunized mice. Right panels: B cell activation was measured by antibody binding to each cell type, shown as mean fluorescence intensity (MFI). Wild type cells exhibit significant antibody binding when incubated with serum from mice that received wt cells. In contrast, hypoimmune-edited cells show only background levels of binding when treated with serum from mice that received hypoimmune-edited cells. Adapted from Deuse et al, Nature Biotechnology 2019.

CD47 is Required to Protect Hypoimmune-Edited Cells from Killing by Human NK Cells

Human iPSCs were differentiated into endothelial cells (hiECs) and plated as a monolayer in a multielectrode system. After exposure to NK cells, monolayer viability was measured electrical impedance, indicated here as normalized cell index. As expected, wt cells were not killed by NK cells. In contrast, cells lacking MHC class I and II (but not expressing CD47 tg; MHC class I/II disruption) were rapidly killed. Addition of CD47 tg prevented killing by NK cells. A blocking antibody to CD47 abolished protection from NK cells, affirming the importance of CD47 overexpression in protection from innate immune cell killing. From Deuse et al, Nature Biotechnology 2019.

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Survival of Hypoimmune-Edited Human iPSC Grafts in MHC-Mismatched Humanized Mice

Wild type (wt) and hypoimmune-edited (MHC class I/II disruption CD47 tg) iPSCs were engineered to express firefly luciferase before transplantation. Emission of light was used as an index of graft cell viability. Sequential light emission scans from the same representative animal receiving wt cells show progressive loss of graft viability, indicating graft rejection, confirmed quantitatively in the line tracings below. In contrast, mice receiving hypoimmune-edited cells show graft expansion over the course of the experiment, indicating immune evasion. From Deuse et al, Nature Biotechnology 2019.

NHP hypoimmune cells transplanted into NHPs

To evaluate immune evasion properties of the hypoimmune cells, we have tested the immune response to and survival of hypoimmune iPSCs from NHPs by transplantation into an allogeneic NHP recipient without immunosuppression.

Design for Allogeneic Study Involving Wild Type (Unmodified) and Hypoimmune NHP iPSC Delivery to NHPs

The study involved a randomized group of eight NHPs distributed into two cohorts of four NHPs each. The first cohort received an initial intramuscular injection of non-edited NHP iPSCs and a second injection of NHP hypoimmune cells at six weeks (i.e., a crossover design). The second cohort received an initial injection of NHP hypoimmune cells, which allowed assessment of immune

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evasion in a naïve recipient. This cohort also received a second injection of non-edited NHP iPSCs, which, with a view towards modeling certain aspects of autoimmune disease, enabled assessment of the impact of injecting hypoimmune cells into an NHP with a pre-existing immune response to non-edited cells. No immunosuppression was administered to any of the animals in the study.

Allogeneic Hypoimmune iPSC Survive in vivo in NHPs with an Intact Immune System

Upper panel: Unmodified wild type (wt) NHP iPSCs (Group 1 top row) or hypoimmune NHP iPSCs (Group 2 bottom row) were introduced via intramuscular injection into allogeneic NHPs. Unmodified NHP iPSCs are undetectable in recipient NHPs by week 3 while hypoimmune NHP iPSCs introduced into naïve NHPs were viable and detectable for 16 weeks post injection. After 6 weeks of the initial injection, NHPs were injected with the cross-over cell type (group 1 with hypoimmune NHP iPSCs and group 2 with wild type iPSCs). In these crossover experiments, hypoimmune NHP iPSCs survived even when the NHP had been exposed to unmodified iPSCs. Unmodified cells injected into NHPs previously injected with hypoimmune iPSCs were rapidly killed with no observable impact on the hypoimmune NHP iPSCs that continued to remain viable. Data are representative for four NHPs receiving HIP iPSCs and wt iPSCs.

Lower panel:  iPSC survival is followed over time in vivo using bioluminescence  imaging (BLI).

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Absence of T Cell, B Cell, or NK Cell Responses Following the First Delivery and Crossover of Hypoimmune NHP iPSCs into NHPs

Upper panel: Immune cells from animals receiving hypoimmune iPSCs showed no response when exposed to hypoimmune iPSCs in vitro (Row 1) in contrast to wt iPSCs (Row 2). Lower panel: Neither unmodified nor hypoimmune-edited cells were susceptible to killing by natural killer (NK) cells, indicating protection from the “missing self” signal. Data above are collected from four NHPs in each experimental arm.

NHP hypoimmune cells grafted into NHPs elicited no detectable systemic immune responses, including no T cell activation and no antibody formation. Innate immune responses mediated by macrophages and NK cells were also undetectable. The transplanted hypoimmune cells were alive and detectable for the duration of the study in these allogeneic recipients (Study duration was 16 weeks for 2/4 NHPs and 8 weeks for 2/4 NHPs. To our knowledge, this is the first instance of prolonged graft survival in an allogeneic transplant setting without immunosuppression in NHPs. In contrast, systemic immune responses from T cells as well as IgM and IgG antibodies were generated to iPSCs without the hypoimmune edits, and the cells were rapidly rejected within two to three weeks.

In the crossover portion of this experiment, injection of NHP hypoimmune cells into NHPs that had previously received non-edited NHPs again elicited no systemic responses as tested in assays for T cell or antibody responses. Similarly, macrophage and NK responses could not be detected. Correspondingly, these cells survived for the full eight weeks that they were monitored suggesting that pre-existing immunity to non-edited human iPSCs had no impact on hypoimmune cell survival. By contrast, in the NHPs that had previously been injected with the hypoimmune cells, the non-edited NHP cells elicited both T cell and antibody responses against the non-edited cells. Notably, these non-edited cells were rapidly rejected (in one to two weeks) in the recipient even as the previously injected hypoimmune cells continued to be viable in the other leg of the NHP. These results provide confirmation that the survival of the hypoimmune allo-graft was not an artifact of an impaired immune system or immune response in the recipient NHP. They also suggest that these hypoimmune cells have the potential for immune evasion even the context of a new immune response toward cells without these edits.

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In light of our preclinical data to date, we believe our hypoimmune technology has the potential to address the most fundamental limitation of ex vivo therapies, persistence, and thereby unlock waves of potentially disruptive therapies across a variety of cell types.

Safety Switch for Hypoimmune Cells

We are actively investigating approaches to control hypoimmune cells after administration into the patient. If necessary, the aim of these “safety switches” would be to provide a mechanism to eliminate hypoimmune cells within the body in a targeted fashion, in scenarios where the cells are not in a location where physical removal is viable. Such a safety switch would be beneficial to mitigate the potential risk of a hypoimmune cell becoming infected with a virus or undergoing oncogenic transformation, in light of the immune evasion modifications to these cells.

One approach we are exploring as a safety switch is to re-sensitize the hypoimmune cells to innate cell killing via administration of a blocking anti-CD47 antibody. We have tested the effectiveness of this approach in iPSCs and teratomas (a particular tumor formed by pluripotent cells with histological features from all three germ layers), both bearing the hypoimmune modifications. Using hypoimmune NHP iPSCs we observed in vitro that the addition of an anti-CD47 antibody binds to and blocks CD47 expressed in the hypoimmune cells and restores the sensitivity to the missing-self killing response mediated by NK cells. We also assessed this strategy in mouse experiments, where the animals were transplanted in with human iPSCs which then formed small teratomas. We have shown that treatment with an anti-CD47 antibody resulted in the loss of immune evasion and the rapid killing of these transplanted cells. We have identified several additional safety switches with in vivo activity and intend to continue to explore them, potentially including multiple safety switches in therapeutic programs moving forward.

Anti-CD47 Administration Results in the Rapid Clearance of Hypoimmune NHP iPSCs in vitro

On left: Hypoimmune NHP iPSCs do not induce killing by NK cells in an in vitro killing assay; On right: by contrast, Anti-CD47 antibody treated hypoimmune NHP iPSCs are no longer able to evade missing-self responses mediated by NK cells and are killed rapidly.

Anti-CD47 Administration Results in the Rapid Clearance of Human iPSCs derived Teratomas in a Humanized Mouse Model

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On left: Human iPSC proliferate (as visualized by luminescence of live cells) and form teratoma in NSG mice (n=3) with adoptive transferred human NK cells. Administration of isotype control has no impact on HIP survival. On right: Blocking of CD47 in vivo results in killing of HIP iPSCs (as visualized by luminescence of live cells) in NSG mice (n=5) with adoptive transferred human NK cells.

CD47 overexpression is differentiated in inhibiting “missing self” response relative to other approaches

As part of our ongoing program to further refine our hypoimmune technology we evaluated the effectiveness of the overexpression of CD47 in comparison to other molecules that have at least some ability to inhibit innate immune responses. We carried out these head-to-head comparisons in K562 cells, a naturally MHC class I and class II deficient cell line. The lack of the MHC class I molecule should result in virtually instantaneous cell killing by stimulated innate immune cells such as NK cells due to the activation of the “missing self” response. We compared three molecules, HLA-E, HLA-G and PDL-1, that have previously been proposed to have a role in inhibiting innate immune responses versus CD47. In this assay, overexpression of these three molecules conferred limited protection from NK cell killing in contrast to CD47 overexpression. This difference in activity may be the result of the more ubiquitous presence of the receptor for CD47 receptor on innate immune cells relative to the presence of receptors for these other immunomodulators. While these results do not rule out a role for these other molecules in inhibiting NK cell responses, they suggest that CD47 may be sufficient to nullify the NK cell-mediated missing-self response.

Panels above show in vitro killing assays mediated by NK cells. Cells missing MHC molecules are killed by NK cells, as measured by rapid decline in cell index. Overexpression of immunomodulatory molecules such as HLA-E, HLA-G or PDL-1 in cells missing MHC molecules did not block NK cell killing. By contrast, overexpression of CD47 blocked NK cell mediated “missing-self” response.

Our ex vivo Cell Engineering Pipeline

Allogeneic T Cell Program (SC291, SC276, SC255)

Our allogeneic T cell program utilizes T cells from healthy donors to generate CAR T therapies that will initially target CD19, a protein expressed on the cell surface of B cell malignancies, to treat patients with refractory lymphoma. We believe that applying the hypoimmune technology to allogeneic T cells gives us an opportunity to create differentiated allogeneic CAR T therapies.

We believe our allogeneic T cell and T cell fusosome discovery programs provide us with two potentially disruptive programs to address the limitations of adoptive T cell therapy for cancer, each with idiosyncratic risks and opportunities. We also believe each approach can address separate and valuable opportunities if they are both successful. Specifically, our allogeneic T cell program offers the opportunity to perform multiple gene edits in a T cell, which may allow us to make intentional modifications to control T cell function or to deliver more complex chimeric receptors and signal integration machinery to enable the T cell to distinguish tumor cells based on surface antigen combinations to improve the specificity of targeting. These approaches may prove especially valuable in

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targeting solid tumors, which have remained largely refractory to CAR T approaches to date. We also have an earlier-stage program looking to differentiate hypoimmune iPSCs into T cells. While we are still working to successfully create the appropriate T cells from an iPSC, we expect that progress with our allogeneic T cell program will also inform the iPSC T cell program. Separately, the fusogen technology allows for the in vivo generation of CAR T cells in a patient, offering a distinct advantage in terms of manufacturability and scalability that may enable the introduction of gene-modified T cells earlier in the course of a patient’s therapy. Additionally, modifying the T cells inside the body without the need for ex vivo manipulation of the cells may generate CAR T cells with more favorable attributes.

We intend to develop our CD19 allogeneic T cell therapies with the goal of submitting an IND for SC291 in 2022. We intend to follow this with SC276, a CD22-targeting allogeneic CAR T which could be combined with targeting CD19 and offers the potential benefit of higher and more durable complete response rates, with an IND submission as early as 2023. We are also advancing our SC255 allogeneic T cell program targeting BCMA for multiple myeloma, with the goal of submitting an IND in the next several years.

Background on B cell Malignancies

B cell malignancies represent a spectrum of cancers including non-Hodgkin Lymphoma (NHL), chronic lymphocytic leukemia (CLL), acute lymphoblastic leukemia (ALL), and multiple myeloma (MM) and result in over 100,000 deaths per year in the United States and Europe. See the subsection titled “—in vivo Cell Engineering Pipeline—Background on B Cell Malignancies” for further background discussion. In addition to our in vivo cell engineering technology, we believe our ex vivo cell engineering technology also has the potential to address B cell malignancies.

Current Treatment Landscape and Unmet Need

We believe our hypoimmune edited cells have the potential to create a differentiated platform for developing allogeneic T cells. There are two major hurdles to the use of allogeneic T cells. The first is the risk of graft versus host disease, in which the allogenic donor T cells target and kill recipient tissues. Multiple CAR T cell product candidates in clinical development have managed to prevent this reaction through gene edits targeting components of the T cell receptor such as TCR-alpha gene. The more significant challenge has been HvGR, in which the patient’s immune system kills the transplanted T cells. One strategy to approach this challenge has been to essentially eliminate the patient’s immune system, neutering its ability to find and destroy the transplanted allogeneic CAR T cells. This strategy has two limitations. First, the patient is at risk of severe infections during this period of substantial immune suppression. Second, as the immune system returns, it will inevitably reject the allogeneic CAR T cells, limiting the duration that these therapeutic cells are in the body. Experience with autologous CAR T cells in patients with B cell malignancies has demonstrated that persistence of CAR T cells is important for the durability of response. Thus, the ability to effectively prevent long term rejection of an allogeneic CAR T therapy without significant immune suppression would be a major advance. We are aware of other efforts to develop allogeneic CAR T cell products that focus on overcoming the adaptive immune system (T and B cells). Our technology addresses rejection mediated by both the adaptive and innate immune systems, giving us the potential to create a differentiated allogeneic CAR T solution.

Our Allogeneic T Cell Program Approach

Our hypoimmune technology is designed to hide the cell from the patient’s immune system, and we are applying this technology to manufacture allogeneic CAR T cells. We intend to utilize T cells from healthy donors into which we will introduce the CAR gene and make the gene modifications necessary to overcome graft versus host disease and to incorporate our hypoimmune technology in an effort to address host versus graft response. We then intend to expand these cells ex vivo, with a goal of making many batches from a single donor as well as creating comparable CAR T cells from various healthy donors. These allogeneic CAR T therapies could be frozen and delivered as an “off the shelf” product for cancer patients without the need for severe immunosuppression.

Preclinical Data

For our preclinical studies, human donor-derived T cells were genetically modified ex vivo, to generate cells bearing the hypoimmune edits (disruption of MHC class I/class II; overexpression of CD47), TCR-alpha disruption (to mitigate graft versus host disease) and the expression of a CD19 CAR. These cells were then tested in vivo for their tumor-killing activity in a human xenograft mouse model for leukemia (Nalm-6). These preclinical data suggest that the hypoimmune edits do not interfere with CAR T killing activity. We observed clearance of the leukemic cells by the hypoimmune CD19 CAR T cells and the potency of these cells was comparable to unmodified CD19 CAR T cells, which are similar to CAR T cells currently in clinical use.

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Hypoimmune Donor-Derived CD19 CAR T Cells Clear Leukemia Cells in a Human Xenograft Mouse Model at Levels Comparable to Unmodified CD19 CAR T Cells

Activity of hypoimmune donor-derived CD19 CAR T in a mouse leukemia xenograft model (Nalm-6). Note that when compared to untreated controls, infusion of unmodified CD19 CAR T or hypoimmune CAR T results in eradication of leukemia cells. Both cohorts of CAR T treated mice had significantly reduced tumor burden when compared to control as early as D7 (p≤0.0001; One-way ANOVA Bonferroni) with no significant difference between either of the treatment arms.

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Furthermore, the hypoimmune CD19 CAR T cells were protected from immune system rejection in humanized mice, and no evidence was observed of either adaptive or innate immune system activation, in contrast to the unmodified CAR T cells:

Absence of T Cell, B Cell, NK Cell, and Macrophage Responses in a Human Xenograft Mouse Model Following Injection of Hypoimmune Donor-Derived CD19 CAR T Cells

Immune cells from humanized animals receiving hypoimmune donor-derived CD19 CAR T showed no response when exposed to hypoimmune CAR T cells in vitro. Delivery of hypoimmune cells did not result in production of donor-specific antibodies, as evidenced by binding of IgM antibodies to the surface of donor cells (increased mean fluorescent intensity, MFI). Hypoimmune-edited cells were not susceptible to killing by NK cells nor macrophages, indicating protection from the “missing self” signal.

Development Plan and Key Next Steps

Process development work is ongoing within the Technical Operations team to develop scalable manufacturing processes to generate quality and consistent allogeneic T cell product candidates. In parallel, our cell engineering team is developing an efficient and specific gene editing platform to enable manufacturing of our allogeneic T cell product candidates.

The next major milestones are to complete Good Laboratory Practice (GLP) studies and GMP manufacturing with the goal of submitting an IND for SC291 in 2022. We believe that early data from the SC291 study will help us understand the therapeutic potential of this therapy, as the ability to evade immune detection with corresponding enhanced persistence of the CAR T may predict higher and more durable complete responses for patients. Additionally, it will give us insight into the potential of this hypoimmune platform for additional CAR T programs targeting other antigens and cancers as well as the potential for the platform more broadly in areas beyond cancer. Following the IND submission for SC291, we are progressing SC276, a CD22-targeting allogeneic CAR T which could be combined with targeting CD19 and offers the potential benefit of higher and more durable complete response rates, with the goal of submitting an IND as early as 2023. We are also advancing our SC255 allogeneic T cell program targeting BCMA for multiple myeloma, with the goal of submitting an IND in the next several years.

Beta Cell Program

Our beta cell program aims to restore lifelong glucose control in Type I diabetes mellitus (T1DM), patients by transplanting hypoimmune iPSC-derived beta cells. Current therapies for T1DM require continual management, and we believe that effectively restoring beta cell functionality will meaningfully improve patient outcomes for patients with T1DM. We intend to develop this program with the goal of submitting an IND for SC451 as early as 2023.

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Background on Type 1 Diabetes

T1DM is an autoimmune disease in which the patient’s immune system destroys its own pancreatic beta cells. The destruction of these cells leads to complete loss of insulin production and a metabolic disease wherein patients are unable to control their blood glucose levels. Often called “juvenile diabetes”, this disease commonly has its onset in adolescence. Beta cells reside in specialized hormone-producing clusters within the pancreas called the Islets of Langerhans. In T1DM, activated T lymphocytes infiltrate the islets and selectively kill the beta cells, progressively reducing the body’s capacity to produce insulin. Once the reserve capacity of beta cells is exhausted, blood glucose rises, and the patient will have a life-long battle to control blood glucose levels.

T1DM affects 1.6 million adults in the United States, and there are approximately 20,000 new cases diagnosed per year in patients under the age of 20. In Europe there are an estimated 2.4 million adults with T1DM, and 300,000 under the age 20, with 31,000 new cases of T1DM diagnosed each year. Combining prevalence in the United States and Europe yields a pool of approximately 4 million patients with T1DM.

Current Treatment Landscape and Unmet Need

Insulin injection is the main treatment option for T1DM. Despite significant advances in types of insulins, glucose monitoring, and insulin pumps, life expectancy for T1DM is still approximately 15 years shorter than for people without diabetes. Patients are at risk from acute complications of hyperglycemia, including diabetic ketoacidosis and coma. Conversely, they are also at risk of hypoglycemic episodes, particularly at night, which can lead to the “dead in bed” syndrome, thought to result from cardiac arrhythmias induced by low glucose. Long term elevations in blood glucose levels have particularly devastating effects on arteries and capillaries, resulting in premature myocardial infarction, stroke, limb ischemia, gangrene, kidney failure, and blindness due to diabetic retinopathy. “Insulin pumps,” which feature a computerized system for sensing blood glucose and delivering appropriate doses of insulin, have improved glycemic control. Notably, data from the FDA indicate that issues with insulin pumps are among the most frequently reported problems in their database. All current therapies require patients to carefully monitor their dietary intake, which, while inconvenient in adults, is a frequent point of failure in adolescents.

Pancreas transplantation for uncontrollable diabetes was first performed in the 1960s, and this established the principle that replacing the beta cells (here in the context of the whole pancreas) could restore physiological glucose control. Pancreas transplants are complicated surgical interventions, require lifelong immunosuppression, and are limited due to organ availability. Nevertheless, some 30,000 pancreas transplants have been performed worldwide to date.

Because of these challenges, the biomedical community began exploring pancreatic islet transplantation in the 1970s. This process involves enzymatic digestion of a donor pancreas and isolation of the Islets of Langerhans followed by delivery of these cells to an appropriate site in the body where the islets can engraft and become well vascularized. The major lessons from islet transplantation have been that glucose homeostasis can be restored, insulin-independence can be achieved, hemoglobin A1C levels (a marker of long-term glucose levels) can be normalized, and severe episodes of hypoglycemia can be reduced. As with an organ transplant, patients must be immune suppressed to prevent immune rejection of the transplanted cells. In addition to complications from this immune suppression and the lack of cell availability, the principal limitation of islet transplantation has been the therapy’s durability. Most patients lose glucose control over months to years and eventually become insulin-dependent again, primarily due to immune rejection of the allogeneic islets.

Our Beta Cell Program Approach

The goal of our beta cell hypoimmune program is to restore lifelong glucose control in T1DM patients by transplanting hypoimmune iPSC-derived beta cells, including beta cells. Our goal is to create a therapy that restores the body’s normal beta cell mass, giving patients physiologically appropriate glucose sensing ability and insulin secretion. We believe this therapy could reduce, or even eliminate, the hypoglycemia and hyperglycemia in diabetic patients, potentially enabling less onerous and costly treatment, fewer complications, and longer life expectancy, resulting in a meaningfully improved quality of life.

We focus our efforts around three goals: (i) deriving highly functional beta cells from PSCs, (ii) genetically modifying these cells to evade allogeneic immune responses, and (iii) genetically modifying these cells to evade autoimmune destruction of beta cells. This strategy requires building on lessons from pancreatic islet transplantation, recent advances in understanding pancreatic islet developmental biology, and our hypoimmune technology.

Deriving beta cells from iPSCs has the potential to solve limitations associated with donor pancreas and improve the overall product quality and product consistency. iPSCs have the potential to create a virtually limitless supply of these cells. Our program uses proprietary differentiation protocols to generate mature beta cells with glucose control comparable to primary human islets, as evidenced by our animal studies. Finally, we intend to modify the genomes of the iPSCs in order to apply our hypoimmune technology. If successful, the hypoimmune gene modifications will protect these cells from both auto-immune and allogeneic rejection

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by the patient’s immune system and potentially remove the need for toxic immunosuppression in transplant recipients. Hypoimmunity also should eliminate the need for physical separation of the beta cells from the rest of the body by a device or encapsulation technology, which may allow for tighter control of glucose by eliminating the lag time between glucose sensing and insulin secretion.

Preclinical Data

We are developing a proprietary protocol that will differentiate hypoimmune iPSCs into mature, glucose-sensitive, insulin-secreting beta cells based on licensed technology from Washington University in St. Louis. This technology enables differentiation of beta cells at a greater purity and with superior function compared to published stem cell-based protocols. The principal function of beta cells is to maintain steady levels of glucose in circulation. The beta cells sense when glucose levels rise in the bloodstream and release insulin in response. In vitro, our beta cells respond to glucose and robustly secrete insulin at an equivalent level to primary human islets, as depicted in the figure below.

Human iPSC-Derived Beta Cells Exhibit Glucose-Induced Insulin Release

Human islets from cadaveric pancreases (gold standard) exhibit robust insulin secretion in response to an increase in glucose levels. Human iPSC-derived beta cells using technology licensed from Washington University in St. Louis show similar dynamics of insulin secretion to the cadaveric islets.

These stem cell-derived beta cells were tested in a mouse model of Type I diabetes induced by the beta cell toxin, streptozotocin. When transplanted into the kidney of the diabetic mice, these beta cells normalize glucose levels in an equivalent fashion to primary human islets. The diabetic glucose levels return when the grafts are surgically excised (nephrectomy). Similar to the human phenotype, diabetic mice cannot normalize circulating glucose levels following a glucose injection. Following transplantation of our beta cells, these mice rapidly normalized blood glucose in an equivalent fashion to both non-diabetic mice and diabetic mice that received human primary islet transplants.

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In vivo Performance of iPSC-Derived Beta Cells in a Mouse Model of T1DM

Top: Normalization of blood glucose levels after transplantation of cadaveric human islet cells or iPSC-derived islet cells obtained by planar or suspension differentiation (Washington University technology). Note the rapid normalization of blood glucose with cadaveric and stem cell-derived islets with the planar protocol, with slower normalization using the suspension protocol. In all groups, removal of the graft by nephrectomy re-induced diabetes, indicating the correction resulted from the transplant. STZ, streptozotocin, is a toxin for beta-islet cells that induces diabetes in animal models. Bottom: Normalization of blood glucose after glucose injection by transplantation of cadaveric islet cells or iPSC-derived islet cells. Note the more complete normalization using the planar protocol. Groups are defined by the same symbols shown in the middle panel. From Hogrebe et al, Nature Biotechnology 2020.

We ran an experiment to better understand whether hypoimmune edits impair the function of islet cells and to confirm that these edits enable the islets to evade immune responses. For these experiments, we made the hypoimmune genetic modifications in human islets isolated from cadaveric human donors. These cells were transplanted intramuscularly, without immunosuppression, into a humanized mouse strain, a mouse strain engrafted with human immune cells that mimic certain aspects of the human immune system. Type 1 diabetes was induced in this mouse model with streptozotocin, and the ability of transplanting islet cells to restore normal glucose levels while evading immune rejection was tested. We found that hypoimmune edited human donor islets were successful in restoring glucose control while unmodified islets failed to do so. The key driver of this difference was that, while human donor islets with hypoimmune edits survived for the full duration of the experiment (approximately 30 days), unmodified islets were rapidly rejected within a week. These data demonstrate that hypoimmune edits do not impair the ability of cadaveric islet cells to restore glucose homeostasis, but they do prevent rejection of these cells in mice with humanized immune systems.

We next tested whether our hypoimmune edited cells could survive in serum containing autoreactive antibodies and T cells from patients with Type I diabetes. We exposed pancreatic islets with or without our hypoimmune edits to serum and T cells from patients with Type I diabetes. As expected, both T cells and antibodies from patients recognize and kill unedited pancreatic islets. In contrast, these T cells and antibodies from Type I diabetics did not recognize or kill our hypoimmune edited islet cells. The results from this experiment increase our confidence that, in addition to preventing allogeneic rejection, our hypoimmune technology may allow islet cells to survive autoimmune killing in patients with Type I diabetes without the need for immunosuppression.

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Hypoimmune human donor pancreatic islet cells evade immune detection and regulate glucose levels

Unmodified human donor derived pancreatic islets (Row 1) are rapidly killed by PBMCs (immune cells) from Type 1 Diabetic donors but are not recognized by immune cells from healthy volunteers. Human donor derived pancreatic islets bearing hypoimmune modifications (Row 2) are not recognized by the PBMCs of healthy volunteers or type 1 diabetics

Left graph: Unmodified human donor derived pancreatic islets (unmodified islet cells) are readily recognized by antibodies in the serum of Type 1 Diabetic patients. Antibody binding is corelated with higher values of Maximum Fluorescent intensity (MFI) Right graph: Human donor derived pancreatic islets bearing hypoimmune modifications are not recognized by antibodies in serum of healthy volunteers or Type 1 diabetic patients

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Hypoimmune human donor pancreatic islet cells survive in humanized mice and regulate glucose levels

Top image panel on left: Unmodified human donor derived pancreatic islets injected intramuscularly into humanized mice are rejected by recipient mice by D9. Viable cells are marked via a bioluminescent marker that is lost when transplanted cells are no longer viable. Top image panel on right: By contrast hypoimmune human donor derived pancreatic islet cells survive in humanized recipient mice till D29 when the experiment was terminated

Lower graphs are serum glucose measurements in the humanized mice. Diabetes was induced via streptozotocin treatment that results in loss of glycemic control as visualized by an immediate and sustained increase in serum glucose. Transplantation of unmodified human donor derived pancreatic islets had no effect on serum glucose levels. By contrast hypoimmune human donor derived islets successfully lowered serum glucose levels as measured by a glucose tolerance test.

Development Plan and Key Next Steps

Our work is currently focused on manufacturing GMP-grade, gene-edited, pluripotent stem cell banks; scaling manufacturing; and characterizing the product. We are working through the process development and IND-enabling studies to allow for an IND submission for SC451 as early as 2023.

GPC Program

Our GPC program aims to deliver healthy allogeneic GPCs, the precursors to both astroglia and myelin-producing oligodendrocytes. This program has the potential to treat myelin and glial-based disorders, which represent a broad group of debilitating neurological disorders, such as multiple sclerosis and a number of neurodegenerative disorders, none of which have effective treatment alternatives. We intend to develop our stem cell derived GPC therapies for secondary progressive multiple sclerosis, Pelizaeus-Merzbacher disease other disorders of myelin, Huntington’s disease, and other astrocytic diseases. Our goal is to submit three INDs for SC379 in the next several years.

Background on Myelin and Glial Based Disorders

Glial cells are the support cells of the human CNS. The two major types of CNS-derived glial cells are oligodendrocytes—the cells that produce myelin, the insulating substance of the brain’s white matter that enables neural conduction and astrocytes, the support cells of neurons and their synapses. These two kinds of glial cells arise from human GPCs (hGPCs), are responsible for remyelination in the injured and demyelinated adult brain and spinal cord.

Diseases of glial cells are among the most prevalent and disabling conditions in neurology. These disorders include the disorders of oligodendrocyte loss and myelin failure and the disorders of astrocytes, which include a number of neurodegenerative and psychiatric disorders. What all these disorders have in common is a significant glial contribution to their pathogenesis, and a lack of disease-modifying treatment options.

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Congenital Leukodystrophies. A number of hereditary disorders of oligodendrocyte loss or dysfunction are characterized by a failure in myelin synthesis or structural stability. Tens of thousands of children in the United States suffer from diseases of myelin loss. The most prototypic example of this class of diseases is Pelizaeus-Merzbacher disease (PMD), an X-linked leukodystrophy most often manifesting in male infants and young boys, caused by mutations in the oligodendrocytic PLP1 gene, which results in widespread hypomyelination. There is no treatment for PMD, which is typically fatal in childhood. We intend to deliver intracerebral transplants of stem cell-derived GPCs to the brains of PMD patients, with the goal of replacing PLP1 mutant oligodendrocytes with healthy cells capable of producing normally compact myelin. Prevalence of PMD in the general population is estimated to be approximately 1 in 100,000 in the United States. While we are initially targeting PMD as our proof of concept, congenital leukodystrophies as a group affect a more significant population, or about 1 in 7,600 births.

Multiple Sclerosis (MS). MS is a debilitating disease characterized by both inflammatory myelinolysis and degenerative axonal loss. There are two major forms, the initial relapsing remitting form, known as RRMS, and its later progressive neurodegenerative phase designated secondary progressive MS (SPMS). RRMS is characterized by clearly defined attacks with new or increasing neurologic symptoms. In contrast, SPMS is characterized by progressive neurodegeneration with a loss of neurons, including those that were previously demyelinated during the RRMS phase of the disease. The demyelination occurs in a diffuse fashion throughout the adult brain and appears to reflect a loss of axonal support by local oligodendrocytes. The delivery of GPCs into such chronically demyelinated brain may offer tangible benefits through the oligodendrocytic engagement of axons, as well as by myelin repair. MS is highly prevalent, with estimates of up to 1.0 million in the United States, 600,000 in Europe, and 2.8 million patients globally. Approximately 85% of MS patients receive a diagnosis of RRMS initially while 15% of patients are diagnosed with primary progressive MS (PPMS). Up to a third of RRMS patients transition to secondary progressive MS within a decade if untreated, and most will progress to SPMS within 20-25 years of diagnosis. Success with a stem cell derived GPC product in SPMS, and especially with a hypoimmune product, could enable further expansion into the RRMS patient population.

Huntington’s Disease (HD). HD is a neurodegenerative disorder in which glial pathology appears to make a significant causal contribution. It is an autosomal dominant disorder characterized by abnormally long CAG repeat expansions in the first exon of the Huntingtin gene. The encoded polyglutamine expansions of mutant huntingtin protein disrupts its normal functions and protein-protein interactions, ultimately yielding widespread neuropathology, most rapidly evident in the neostriatum. We have found that glial pathology is a major contributor to the functional deficits of HD and repairing the glial pathology has significant and positive effects in animal models. There are approximately 41,000 symptomatic Americans and more than 200,000 at-risk of inheriting HD. In Europe, there are approximately 50,000 patients with HD.

Current Treatment Landscape and Unmet Need

Congenital Leukodystrophies. There are no viable treatment options for these conditions, only supportive and palliative therapies for symptoms as they present.

MS. Current treatments for MS are largely limited to treatments for RRMS; few treatments are approved for SPMS, and these have at best marginal efficacy in delaying disease progression; none are restorative. Currently approved treatments for RRMS may be divided into three broad categories of disease modifying therapies: (i) first line injectables (such as beta-interferons, Copaxone), (ii) newer oral agents (such as Tecfidera, Gilenya, Mayzent, Zeposia), and (iii) high-efficacy agents (such as Tysabri, Lemtrada, Ocrevus). Despite many recently successful drug launches in the RRMS space, these drugs still only slow the progression of disease and aid in the recovery from attacks, and there remains no treatment that confers functional restoration or effective cure for this disease.

HD. Currently, there is no treatment to stop or reverse Huntington’s disease. Treatment is limited to several medications that can help minimize symptoms, including the drug tetrabenazine, antipsychotic drugs, antidepressants, and tranquilizers.

Our GPC Program Approach

Our approach to treat myelin and neurodegenerative disorders is via the delivery of healthy allogeneic stem cell-derived GPCs. We have developed methods for producing and isolating these cells from pluripotent stem cells and delivering them in the purity and quantities necessary for their replacement of endogenous diseased cells. We believe that both the myelin disorders and glial-based neurodegenerative conditions have compelling potential for our ex vivo therapy.

Preclinical Data

Congenital Leukodystrophies. The capacity of stem cell-derived GPCs for remyelination has been conducted in animal models of congenital hypomyelination. Our collaborators used newborn shiverer mice that have a genetic defect in myelin basic protein (MBP), resulting in their neurons being hypomyelinated and the mice having a shortened lifespan. When iPSC-derived hGPCs were transplanted into these mice, the cells spread widely throughout the brain, developing as astrocytes and oligodendrocytes. These oligodendrocytes generated mature myelin that effectively restored neuronal conductance and prolonged survival in the transplanted

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mice. We believe that these data suggest the feasibility of iPSC-derived hGPC implantation in treating childhood disorders of myelin formation and maintenance, as depicted in the figure below:

hGPCs myelinate widely to greatly extend the survival of hypomyelinated mice. A, Dot map indicating distribution of human iPSC-derived GPCs at 7 months of age, following neonatal engraftment in a shiverer mouse brain. Widespread colonization and chimerization of the host brains by iPSC-derived hGPCs is evident (human nuclear antigen, red). B, iPSC-derived hGPC-derived myelination in shiverer forebrain, at 7 months; section 1 mm lateral to A. Myelin basic protein (MBP)-immunoreactivity (green) is all human donor-derived. C, D. Myelination in sagittal sections taken at different mediolateral levels from 2 additional 7 month-old mice, each engrafted with iPSC-derived hGPCs at birth. E, Kaplan-Meier plot of survival of iPSC-OPC implanted (n=22) vs. saline-injected (n=19) control mice. Scale: A-B, 2 mm. Adapted from Wang, Cell SC 2013.

MS. Our prior studies established the ability of stem-cell derived hGPCs to myelinate the developing shiverer brain and rescue the afflicted mice; however, the experimental subjects were neonates, not adults. Until recently, it was unclear whether GPCs are able to migrate extensively in adult brain tissue, as would be required for the repair of diffusely demyelinated adult brains. To explore whether the introduction of stem-cell derived hGPCs delivered directly into the adult brain could remyelinate axons in the setting as might be encountered clinically in multiple sclerosis our collaborators studied three different biologic models. First, it was shown that stem-cell derived hGPCs can disperse within and myelinate the brains of adult shiverer mice (as depicted in the figure below). Second, it was shown that neonatally-engrafted hGPCs engrafted as a neonate can generate new oligodendrocytes and remyelinate demyelinated axons after chemically induced demyelination. This result demonstrated the ability of already-resident hGPCs to remyelinate previously myelinated axons after a new demyelinating insult as an adult, as well as the ability of transplanted hGPCs to reside as a functional reservoir of new myelinogenic cells in the host brains. Third, it was shown that hGPCs transplanted into the adult brain after chemically induced demyelination can remyelinate denuded axons. These data suggest that transplanted hGPCs can disperse broadly and differentiate as myelinogenic cells in the adult brain, and that they are able to remyelinate demyelinated axons and white matter lesions of the brain after an insult as an adult.

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hGPCs Mediate Robust Myelination After Transplantation into the Adult Shiverer Brain

Human GPCs proved both highly migratory and robustly myelinogenic, after delivery to the hypomyelinated adult shiverer x rag2-/- brain. A, By 19-20 weeks of age (mice were injected as post-weaning adults, at 4-6 wks) the injected cells had dispersed broadly throughout the forebrain white matter. B, hGPCs delivered to myelin wild-type rag2-/- mice distributed throughout both gray and white matter. C, Oligodendrocyte differentiation and myelinogenesis by donor hGPCs was robust, with myelination of brain regions that would typically be demyelinated in shiverer mice D, a higher power image of C shows the high proportion of donor cells in those brain regions. Note that DAPI marks all nuclei, hN marks the hGPCs, and MBP marks the remyelinated regions in C and D. From Windrem et al, Cell Reports 2020.

HD. Our collaborators explored the cellular basis for HD related glial pathology and identified significant defects in potassium channel and glutamate uptake mechanisms in HD glia, which appeared to account for both the glial pathology and its deleterious effects on synaptic function. Together, these studies suggest a critical role for glial pathology in the progression of HD and suggested the potential for glial cell replacement as a therapeutic strategy in HD, and more broadly, to other neurodegenerative diseases in which glial pathology might be causally contributory. It was confirmed in preclinical mouse studies that stem-cell derived hGPC transplant ameliorated both the neuronal and glial pathology of HD by restoring synaptic homeostasis and normal synaptic function to the most affected regions of the host brain.

The majority of the studies with human GPCs thus far have been xenogeneic grafts of human GPCs to neonatal or adult mice or rats (and in a small sample POC study limited to adult tissue-derived hGPCs, NHPs). Our collaborators have also performed studies with murine GPCs transplanted into both developing and adult mice, which have confirmed allogeneic GPC migration and integration. However, we have no assurance that human GPC engraftment of human brain will result in the widespread migration and colonization of host brain that is seen with xenogeneic grafts. To better model the human-to-human graft paradigm, our collaborators have established a new model to evaluate if GPC engraftment will result in migration and colonization in a host brain. This model allows observation of the competitive interactions of the two separately tagged human GPC populations. The human-into-human grafts expanded and integrated well in their humanized host, with competitive interactions. As might be anticipated in the clinical setting of healthy cells being transplanted for the purpose of replacing lost or diseased hGPCs, the healthy donor cells outcompete both diseased and older cells to ultimately colonize the hosts. These data have provided preclinical assurance of the fundamental premise of our approach, that healthy human donor cells can replace lost or diseased human cells in vivo. That said, this determination remains to be made in patients.

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GMP Grade Stem Cell Derived hGPCs for Clinical Studies

A protocol to direct differentiation of human ESCs, as well as iPSCs, to hGPCs has been established. These hGPCs cells remain bipotential for astrocytes and oligodendrocytes, and they differentiate to either fate depending on local signaling.

This protocol has been transferred to a GMP facility in order to enable production of clinical grade cells for both safety and efficacy testing. These cells have been validated to robustly remyelinate shiverer mouse brains upon intracerebral transplantation. We plan to use these cells for our IND-enabling studies and initial clinical trial material.

Development Plan and Key Next Steps

Progression of SC379 to IND is planned to follow completion of definitive safety and toxicology studies. Definitive preclinical efficacy studies using the anticipated clinical product are also planned and will replicate studies that we have published. Since GPCs are not a terminally differentiated cell type and divide and differentiate in vivo post-transplantation, we will continue to assess potential safety risks, including the risk of tumorigenicity. We expect to submit IND applications for SC379 for SPMS, PMD, and HD in the next several years.

Cardiomyocyte Program

Background on Heart Failure

Heart failure (HF) is a classic example of a disease of cell loss, ideally suited to the application of ex vivo engineered cells. The clear but ambitious goal of our program is to replace missing cells after a myocardial infarction, commonly known as a heart attack, in an attempt to restore heart function and improve outcomes for patients. HF is a life-threatening syndrome, and patients with HF have a mortality rate of 20-30% within one year of diagnosis and a mortality rate of around 50% within five years of diagnosis.

HF with reduced ejection fraction (HFrEF), is a severe form of HF where heart muscle is unable to contract, and therefore pump, adequately. HFrEF is most frequently a consequence of a loss of heart muscle cells (cardiomyocytes), following a myocardial infarction. In the United States, there were approximately 380,000 deaths associated with HF in 2018 according to the United States Centers for Disease Control and an overall prevalence of approximately 6 million people with HF, with similar numbers in Europe.

In general, HF has been a challenging area for drug and device development, including only one new drug, Entresto, approved in the last 20 years, and a limited number of devices introduced including electrical resynchronization therapy and implantation of left ventricular assistance devices (LVADs). These approaches provide only symptomatic relief and do not address the underlying loss of cardiomyocytes associated with HFrEF. As a result, HFrEF currently remains a progressive and deadly disease with a large unmet need worldwide.

To date, efforts to develop cell-based therapies to address this unmet need have provided little evidence of clinical benefit. Importantly, these attempts have typically utilized cells such as bone marrow-derived mononuclear cells and mesenchymal stromal cells where any potential benefit would be limited to paracrine mechanisms and not the direct replacement of lost cardiomyocytes.

Our cardiomyocyte program aims to directly regenerate the heart, by replacing lost cardiomyocytes with iPSC-derived cardiomyocytes, with the goal of restoring heart muscle and increasing ejection fraction, which is the percentage of blood the heart pumps with each heartbeat. Replacement of lost cardiomyocytes with iPSC-derived cardiomyocytes that engraft and function correctly has the potential to prevent or even reverse the progression of HFrEF.

Developing an ideal stem cell-derived cardiomyocyte therapy involves many steps, including:

Differentiating Cardiomyocytes at Scale that Engraft, Beat Correctly and in Synchrony with the Host Heart Muscle, and Improve Host Heart Function

Scientists, including Dr. Chuck Murry, our Senior Vice President, Head of Cardiometabolic Cell Therapy, have been working for over 20 years towards developing a regenerative therapy for HFrEF with the goal of transplanting cardiomyocytes derived from

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human pluripotent stem cells that engraft, function, and persist in the human heart in vivo. The groundwork for potential future clinical development has been laid by key breakthroughs such as the ability to direct the differentiation of stem cells selectively into cardiomyocytes, including producing pharmaceutical grade cardiomyocytes at large scale in bioreactors, and the ability to transplant such cardiomyocytes to induce remuscularization of injured hearts.

Initial preclinical attempts to remuscularize the infarcted heart were unsuccessful due to death of the transplanted cells within a few days of delivery. None of the animals with failed engraftment showed improvement in cardiac function, indicating that engraftment is essential for functional improvement. Our collaborators developed a pro-survival cocktail that kept cells alive through the rigors of transplantation, allowing the cardiomyocytes to self-assemble into new muscle tissue and induce ingrowth of new blood vessels and connective tissue from the surrounding heart muscle. Once engraftment was successful, cardiac function improved. As our collaborators’ capabilities to scale cell manufacturing increased, studies progressed from mice to rats to guinea pigs, all showing improved function:

Human ESC-Cardiomyocytes Improve Function in Injured Rat and Guinea Pig Hearts

Left panel: functional rescue in rat. All groups showed comparably reduced fractional shortening after infarction at 2 days pre-transplantation (Pre-Tx). At 28 days post-transplantation there was preservation of fractional shortening in animals receiving hESC-cardiomyocytes, with deterioration of function in all other groups. PSC, pro-survival cocktail. SFM, serum-free media. **p<0.01; # p<0.05 vs. 2 days Pre-Tx. Right panel: functional rescue in guinea pig. Following cardiac injury at 2 days before transplantation, all groups showed comparably reduced fractional shortening. At 28 days post-transplantation there was preservation of function in animals receiving hESC-cardiomyocytes (hESC-CM), with deterioration of function in other groups. *p<0.05. **p<0.01. †p<0.05 vs 2 days Pre-Tx. From Laflamme et al, Nature Biotechnology 2007 (left) and Shiba et al, Nature 2012 (right).

Current methods demonstrate regeneration of the hearts of large animals including pigs and NHPs by transplanting human ESC-derived cardiomyocytes (hESC-CM). The figure below shows low magnification microscopic images from NHP hearts that were infarcted and then received either hESC-CM or saline controls. The replacement of heart muscle by scar tissue is evident in the saline-treated heart, whereas human heart muscle has repopulated the infarct in the hESC-CM treated group.

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Remuscularization of the Heart of an NHP by hESC-CM Transplantation

The saline-treated heart (left) shows infarct scar tissue (blue) replacing the myocardium lost to infarction. The hESC-CM treated heart (right) shows a large graft of human heart muscle (green) replacing the myocardium lost to infarction. From Liu et al, Nature Biotechnology 2018. Scale bar, 5 mm.

We conducted an experiment to help us understand the mechanism of action and learn whether the transplanted muscle beat in synchrony with the host heart muscle. hESC-CMs were genome-edited to express a protein that fluoresced green with each contraction, and their behavior was studied after transplantation into an infarcted macaque heart. hESC-CMs showed 1:1 synchrony with the host heart, indicating that the graft follows the heart’s natural pacemaker, an essential result for heart regeneration.

A final question was whether this regeneration improves the function of the injured heart. To assess this, engrafted NHP hearts were studied by magnetic resonance imaging (MRI), the gold standard for assessing cardiac contractile function. As illustrated in the figure below, myocardial infarction induced a 25-point drop in left ventricular ejection fraction, the fraction of blood ejected from the heart with each beat.

Control animals receiving a saline injection showed no significant improvement at 4 or 12 weeks, as expected. In contrast, four weeks after receiving hESC-CMs, ejection fraction improved by approximately 10 points, and by 12 weeks, it had improved by a total of approximately 22 points. While the number of animals followed for 12 weeks is limited, cardiac remuscularization in this study restored ventricular function back into the normal range. In contrast, the current standard of care for myocardial infarction, including reperfusion via angioplasty, ACE inhibitors, and beta blockers, increases ejection fraction by approximately 6 points.

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Restoration of Cardiac Function in NHPs by Transplantation of Human ESC-derived Cardiomyocytes (hESC-CM)

Myocardial infarction reduces ejection fraction (a measure of cardiac function), and there is no spontaneous recovery in control animals receiving a saline injection (gray). All animals receiving hESC-CM (blue) showed significant improvement by 4 weeks, and by 12 weeks after treatment, cardiac function was restored to the normal range.

In summary, structural data demonstrating extensive remuscularization of the infarcted heart in conjunction with physiologic and pharmacodynamic data provide evidence that the transplanted cardiomyocytes directly restore heart contractile function.

Engineering the cells to avoid rejection due to the host immune response to the transplanted cells

Initially, we plan to establish safety with first-in-human clinical trials of our cardiomyocyte cell therapy using immunosuppression to reduce the risk of a host immune response to allogeneic transplanted cells and the potential immune rejection. Our collaborators have studied immunosuppressive regimens in NHP by transplanting rhesus cardiomyocytes derived from stem cells into the hearts of mismatched recipient NHP. An immunosuppressive regimen was identified that keeps the allogeneic grafts alive long term and is considerably less toxic than regimens used for heart transplantation. However, an approach that obviates the need for an immunosuppression regimen has the potential to improve safety and patient eligibility. Therefore, as part of our program lifecycle we intend to switch to a hypoimmune stem cell-derived cardiomyocyte over time, as this should allow us to eliminate or reduce the immune suppression required for durable maintenance of these cells.

Addressing the risks associated with potential transient arrhythmias, or abnormal heart beats, following cell transplantation

The term engraftment arrhythmia refers to a transient period of unstable electrical activity that occurs in some species over approximately four weeks following cardiomyocyte transplantation. Engraftment arrhythmias were not observed in mice, rats, or guinea pigs (probably because their natural heart rates are too fast), but they are observed in NHPs, where they cause mild symptoms, and in farm pigs, where they cause more significant symptoms. The arrhythmias follow a stereotypical course, where they increase in frequency and duration, plateau for a variable period, and then wane until the heart has normal rhythm once again. Once the heart rhythm stabilizes, the arrhythmias seem to disappear permanently. We are exploring three ways to address engraftment arrhythmias: pharmaceutical interventions, genetic modifications to the cardiomyocytes, and adjusting the stage of differentiation of the cardiomyocytes. Electrical mapping studies in NHPs and pigs suggest that the engraftment arrhythmias originate from the site of the cell injection, likely from the injected cardiomyocytes. The stem-cell derived cardiomyocytes in these experiments are more similar to fetal cardiomyocytes than their adult counterparts, and while this favors their engraftment it potentially increases the risk for the

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induction of arrhythmias. We compared the expression and function of ion channels, proteins regulating the electrical properties of cardiomyocytes, in immature versus mature cardiomyocytes. We identified multiple ion channels which showed differential activity, including HCN4, CACNA1H, and SLC8A1 which are active, as well as KCNJ2 which is inactive, in immature cardiomyocyte relative to mature ones. We subsequently assessed the impact of modulation of a variety of combinations of ion channels in animal studies. We found that PSC-derived cardiomyocytes in which the expression of HCN4, CACNA1H, and SLC8A1 has been abolished and the expression of KCNJ2 has been activated (“MEDUSA cells”) creates cardiomyocytes that lack endogenous pacemaking ability but can follow exogenously supplied electrical stimulation. MEDUSA cells robustly engraft but do not induce arrythmias in a pig model. We are currently testing whether MEDUSA cells can effectively restore heart function in infarcted NHPs as well as the longer-term potential impacts of modifying these ion channels in cardiomyocytes.

MEDUSA cells do not induce arrythmia after transplantation in a pig model

Wildtype stem cell-derived cardiomyocyte grafts induce arrhythmias after transplantation into pig hearts (blue circles), shown by the rise in heart rate and the increased arrhythmia burden (percentage of day spent in arrhythmia). Black circle indicates one wildtype animal that died from complications of the arrhythmia. In contrast, MEDUSA-edited cardiomyocytes (3 KO/1 OE; orange squares) do not induce arrhythmias.

Immunostaining for human cardiac muscle (human-specific slow skeletal troponin I stain, brown) demonstrates large grafts of human myocardium in the heart of a pig receiving MEDUSA cells. Thus, absence of engraftment arrhythmia is not due to absence of engraftment.

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Development Plan and Key Next Steps

Our key milestones include understanding any potential impact on function and safety of these MEDUSA edits, their ability to protect longer-term from the risk of arrhythmias, completing GLP toxicology studies, and additional efficacy and safety studies in NHPs and pigs, with the goal of submitting an IND in the next several years. We plan to finalize our clinical plan based on the results of ongoing studies in NHPs using the MEDUSA edits in stem-cell derived cardiomyocytes as well as early results from humans in other settings with our hypoimmune platforms.

Our in vivo Cell Engineering Platform

Overview

In vivo cell engineering aims to treat human disease by delivering a therapeutic payload to cells inside a patient’s body to repair or control genes. Historically there have been four key challenges to in vivo cell engineering:

Our in vivo cell engineering platform is focused on engineering fusogens that, when combined with delivery vehicles, can effectively deliver a payload to a desired cell or location in the appropriate quantities in vivo. The combination of a fusogen with a delivery vehicle referred to as a fusosome. We believe our platform provides us with the flexibility to deliver a wide range of payloads to make different modifications for different diseases, as well as delivery vehicle options to address volume of distribution and re-dosing, which could fundamentally expand the treatment potential of in vivo therapies.

Our Approach to Building our in vivo Cell Engineering Platform

We have approached the development of our in vivo cell engineering platform by investing in solutions to overcome the key challenges outlined above:

Our Approach to Building our in vivo Cell Engineering Portfolio

We have prioritized cell types for our programs where:

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Based on this prioritization, we are initially focused on three cell types: T Cells, Hepatocytes, Hematopoietic Stem Cells

History of in vivo Cell Engineering and Current Limitations

Starting several decades ago, the nascent field of gene therapy focused on experimenting with different means of transmitting genetic payloads via viral vectors. Seminal work by Dr. Richard Mulligan, our Executive Vice-Chairman and Head of SanaX, and colleagues established the promise of gene therapy by delivering genes into host chromosomes, thereby correcting genetic deficits. More recently, significant investments have resulted in improved safety and efficacy of viral vectors. However, most approaches continue to concentrate on adapting the innate capabilities of various viruses to transmit these payloads.

Profound benefits have been realized in cases where there is direct correlation between the biological activity transmitted by the therapy and the genetic activity that is missing in the patient. AAV vectors, which are broadly used by gene therapy researchers due to their broad tissue tropism, lack of pathogenicity, and ability to target both dividing and non-dividing cells. While these therapies have had a categorical impact on their target patient populations, they have only scratched the surface of the potential of in vivo cell engineering, with success limited to a small number of patients.

Broad impact of gene therapies has been limited by challenges within three key areas:

Payload delivery is limited by:

Genome modification is limited by:

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Execution in manufacturing is limited by:

Our Solution – Fusogen Technology

To address some of the existing challenges of in vivo cell engineering, we are developing our fusogen technology by engineering proteins found in nature to enable the delivery of any payload to specific cells.

Background on Fusogens

Fusogens are a well-studied class of naturally occurring proteins that mediate the trillions of cell-to-cell and intracellular fusion events occurring in the human body every second. In 2013, the Nobel Prize in Physiology or Medicine was awarded for the elucidation of the roles of fusogens in mediating intracellular trafficking in nature. First, fusogens enable recognition of a specific target membrane. Second, they promote membrane fusion by acting as thermodynamic engines for opposing membranes, pulling them together and thereby promoting fusion.

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Our Fusogen Technology

Fusogens are widely used by enveloped viruses to confer target specificity and to drive the process of introducing material in target cells. A well-known current example of a viral fusogen is the SARS-CoV-2 coronavirus that causes COVID-19. This virus uses its spike glycoprotein to target cells expressing the ACE2 receptor and to fuse with the cell membrane of host cells and release the viral genome into the cell. Many other biological processes utilizing fusogens for the delivery of complex, diverse, and large payloads to specific cell types have also been found. For example, the process of fertilization occurs as a result of a sperm fusing specifically with the egg and the transfer of the paternal genetic material to the oocyte. Similarly, the fusion of myoblasts with other myoblasts is essential for the formation, growth, and regeneration of skeletal muscle. The myoblast delivers an entire novel nucleus to the muscle cell, highlighting the utility of this system to deliver quite large and complex payloads. These and a myriad of other processes rely on this vast class of protein machines.

Applying fusogens to in vivo cell engineering

Building on both our team’s deep understanding of fusogen biology and extensive research in protein engineering, we are developing a technology designed to allow us to engineer the biological properties of these naturally occurring proteins. In doing so, we are developing a highly modular system that can specifically target numerous cell surface receptors and thereby deliver diverse therapeutic payloads to a variety of cell types.

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Our current programs use fusogens derived from a virus from the paramyxoviridae family. The fusogen protein complex is comprised of two proteins: the receptor recognition G protein and membrane fusion F protein. The combination of a fusogen with a delivery vehicle such as a gene therapy vector or lipid vesicle is referred to as a fusosome. The diagram below depicts the mechanism of fusogen-mediated membrane fusion. This protein complex is found on the outer membrane of the fusosome (1). As the fusosome interacts with cells, only those with the target receptor will engage the G protein of the fusogen complex (2). The binding of the G protein to the receptor stimulates the F protein to initiate its membrane fusion activity. The F protein first partially unfolds to bind to the target membrane (3) and then refolds to bring the target and fusosome membranes in proximity (4), to ultimately promote membrane fusion (5), and subsequent payload delivery.

Mechanism of Fusogen-Mediated Membrane Fusion

The G protein has the potential to be engineered for a high degree of cell selectivity. To accomplish this, we first engineer the G protein so that its natural binding domain is no longer functional. We then add a targeting scaffold to the G protein that re-directs the fusogen to a cell-specific receptor. The targeting scaffold can be any one of naturally occurring or synthetic single chain affinity binders, such as single chain variable fragment (scFvs), camelid single-domain antibodies (VHHs), or designed ankyrin repeat proteins (DARPins). Finally, we iteratively rebuild our fusogen using insights from protein engineering to improve titers, or potency. By serially swapping different targeting scaffolds we believe we can target multiple different cell surface receptors, giving us the ability to target many different cell types.

Re-targeting the specificity of the G-protein is a challenging protein engineering problem, since altering the protein structure directly impacts all aspects of biological function. However, once we have achieved the desired specificity and potency for a certain cell type, we have the ability to deliver a variety of payloads to that cell. This feature of the technology should allow us to create multiple therapies targeting a variety of diseases with each successful fusogen. As a result, we believe success with any initial therapy targeting a given cell type could meaningfully advance lead candidate selection for other indications and increases our confidence that we will be successful with subsequent therapies targeting that same cell type. For example, a successful hepatocyte-targeting fusogen applied to a fusosome for a given monogenic liver disease meaningfully accelerates lead candidate selection and increases our confidence that we will be successful with subsequent therapies targeting hepatocytes.

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Addressing key in vivo cell engineering challenges

We believe that our in vivo cell engineering platform enables us to address key challenges associated with successful in vivo cell engineering – payload delivery, genome modification, and execution in manufacturing:

Payload delivery

High cell specificity for diverse cell types. We believe we can engineer fusogens with cell specificity to maximize on-target effects, while reducing or eliminating off-target risk. In our research, we have used fusogens to successfully target numerous cell surface receptors and cell types. As an example, in preclinical studies, we have demonstrated that our fusogens can specifically target CD8, CD4, or CD3 T cells (see the subsection titled “Our in vivo Cell Engineering Pipeline—T cell Fusosome Program”), potentially enabling delivery of a payload in vivo to transduce specific T cell populations and enabling targeted cell killing through the creation of CAR T cells.

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Engineering Fusogens to Target a Variety of Cell Types

Figure A depicts the increased transduction efficiency (measured in titer) of a fusogen engineered for targeting CD20 on receptor enriched B cells as compared to B cells that were negative for the receptor. Similar transduction efficiency was also observed in an engineered fusogen targeting a neuronal surface protein, GRIA4, as depicted in Figure B. Neuronal-specific transduction of the Green Fluorescent Protein (GFP) payload in the murine hippocampal region was observed using a fusosome specific for GRIA4 when injected into the hippocampal space (as depicted by the green coloring in Figure D) compared to widespread transduction when using a VSV-G fusogen (Figure C). Confirmation of neuron-specific targeting of the fusogen can be observed by the colocalization of GFP positive cells (green, Figure E) with the presence of a neuron-specific protein (NeuN in red, Figure F) and considering the high degree of overlap (colocalization seen as yellow, Figure G). Figures C-G from Anliker et al, Nature Methods, 2010.

Broad volume of distribution. Our SanaX business unit is actively working on next generation approaches to broaden the volume of distribution, including exploring cells as fusosome delivery vehicles.

Immunogenicity. We have initially focused our efforts on selecting fusogens for which the general population does not have pre-existing immunity. We are also working with a number of fusogens that exist naturally in humans, as neither these native fusogens nor re-targeted versions are likely to induce an immune response, making re-dosing more readily attainable.

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Genome modification

High degree of payload flexibility. We have successfully delivered a variety of payloads including DNA, RNA, and proteins, using viral delivery methods and have used cells engineered to express specific fusogens to deliver organelles to a broad range of target cells. We believe this provides us the opportunity to potentially intervene in a wide range of human diseases.

Diverse Payload Delivery via Fusosomes

Cre protein loaded cell-based fusosomes delivered recombinase activity to cells that activated the expression of a red fluorescent protein in cells already expressing green fluorescent protein, seen as orange cells (Figures A, B). In contrast, fusosomes in which the fusogen is not included, but only contain Cre protein, showed no recombinase activity, or no orange cells (Figure C). Fusosomes loaded with fluorescently labeled RNA showed cellular localization and green fluorescence consistent with cytoplasmic delivery and translation of delivered RNA (Figures D-G). Flow cytometric analysis showed cellular uptake of fluorescent RNA (Cy5, Y axis) and GFP expression from the RNA (GFP, X axis) (Figure H). Importantly, the inclusion of a fusogen in the fusosome dramatically increased GFP expression due to the translation of the RNA. Cell-based fusosomes delivered red fluorescent mitochondria with respiration activity to cells with respiration-negative green mitochondria, (Rho0 cells) shown in Figure I. An increased oxygen consumption rate (OCR), due to respiration, was seen in Rho0 cells after Fusosome-mediated delivery of active mitochondria using two distinct fusogens (Figure J).

Expanded payload capacity. Our current fusosome has approximately twice the genetic capacity of the commonly used AAV vectors. This greater payload size increases the potential of addressing defects in larger genes or conditions where delivery of multiple genes may be required. Our research efforts include other fusosomes with even larger payload capacities. For example, utilizing a cell as the delivery vehicle can confer an almost limitless capacity.

Durability limitations. We can engineer our fusosomes to integrate into the target cell genome or to deliver non-integrating payloads. Integrated payloads allow the genetic information transmitted by the vector to be propagated durably with the genetic material of the target cell when it undergoes cell division. Thus, conditions that require this type of genetic propagation, such as genetic diseases in essential genes functioning in growing tissues or in T cells expanding after recognizing a target antigen, can be better addressed by this approach. Our preclinical studies have also demonstrated the ability to deliver gene-editing machinery, such as CRISPR, with this system. In this case, the entire payload does not integrate, but instead, it transiently delivers the machinery to

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permanently modify the DNA in the target cell. Thus, we are able to make targeted, specific, and durable repairs to the genome of the target cell.

Execution in Manufacturing

Manufacturing of cell and gene therapies remains complex due to incumbent challenges in areas such as product consistency, process robustness, and scalability. Our fusosome approach has significant advantages over current solutions. Targeted delivery of complex payloads in vivo has the potential to create autologous, gene-modified cells without the complexities of ex vivo manufacturing. We believe that these therapies have the potential to have greater product consistency, improved scale, and lower costs than current autologous solutions. Currently, there are a number of therapies either approved or in development for ex vivo modification of autologous T cells and autologous HSCs. Additionally, vectors that deliver payload to random or off target cells not only create the risk for toxicities, but they necessitate meaningfully larger doses in order to ensure adequate delivery to the targeted cells. Our targeted delivery offers the potential for meaningfully lower doses, which could decrease scale needs in manufacturing.

Further, we are investing across a number of areas to improve manufacturing scale, costs, consistency, and product quality in the near-term and long-term, including by establishing and maintaining our relationships with our CDMO partners and investing in establishing and operating our own GMP manufacturing facility. Manufacturing novel fusosome compositions is complex. Since our inception, we have invested in scientific and process engineering expertise to improve manufacturing of our therapies. Examples include novel producer cell lines, novel processes and analytical technology, as well as incorporating suspension bioreactors into our process early in the research phase. By building out these capabilities early, we hope to improve the probability of technical success for our programs and have a thoughtful approach to deliver consistent supply while managing cost of goods with the goal of improving patient access.

Our in vivo Cell Engineering Pipeline

T Cell Fusosome Program (SG242, SG295, SG233, SG221, SG239)

Our most advanced CAR T cell fusosome product candidates (SG242, SG295) target CD19+ cancer cells, including NHL, CLL, and ALL. We intend to develop these product candidates with the goal of submitting an IND as early as 2022. In parallel with the CD19 CAR product candidates we are developing other CAR T cell therapies, including BCMA product candidates for the treatment of multiple myeloma (SG221, SG239), CD22 product candidates for the treatment of NHL, CLL, and ALL (SG233), as well as other targets on a spectrum of cancers.

Background on B Cell Malignancies

B cell malignancies represent a spectrum of cancers including non-Hodgkin lymphoma (NHL), chronic lymphocytic leukemia (CLL), acute lymphoblastic leukemia (ALL) and multiple myeloma (MM) and result in over 100,000 deaths per year in the United States and Europe.

NHL is the most common cancer of the lymphatic system. NHL is not a single disease, but rather a group of several closely related cancers. Over 77,000 cases of NHL are diagnosed annually in the United States and the most common subtype of NHL overall is diffuse large B cell lymphoma (DLBCL). DLBCL, if left untreated, may have survival measured in weeks or months.

CLL is the most common type of leukemia, and it occurs most frequently in older individuals, with diagnoses in people under 30 years of age occurring only rarely. Each year, approximately 20,000 patients are diagnosed with CLL in the United States. Approximately 20–25% of CLL patients initially present with poor risk disease. Median progression-free survival in these high-risk groups is often less than 12 to 18 months after frontline therapy, and less than 12 months in R/R disease.

ALL is an uncontrolled proliferation of lymphoblasts, which are immature white blood cells. The lymphoblasts, which are produced in the bone marrow, cause damage and death by inhibiting the production of normal cells. Approximately 6,000 patients are diagnosed with ALL in the United States each year, the vast majority of the approximately 1,500 deaths per year occur in adults. Approximately 80% of cases of ALL in the United States and Europe are B cell ALL, which almost always express the CD19 protein. The five-year overall survival in adults over the age of 60 with ALL is approximately 20%, and in patients with R/R ALL after two or more lines of therapy, the median disease-free survival is less than six months. B cell ALL is the most common cancer in children. Although children with ALL fare better than adults, children with R/R disease have poor outcomes. Because of the frequency, ALL remains a leading cause of death due to cancer in children.

Multiple myeloma is a cancer of the plasma cells, which typically express a protein called B Cell Maturational Antigen (BCMA). Plasma cells are B cells that have matured to specialize in the production of antibodies. Multiple myeloma is a condition in which these plasma cells become malignant, with a single clone growing at an uncontrolled pace. These myeloma cells secrete large

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quantities of the same antibody, and patient symptoms can develop from the myeloma cells crowding out other plasma and bone marrow cells, leading to increased risk of infection, risk of bone destruction, and kidney disease. Multiple myeloma is the second most common hematologic malignancy making up approximately 2% of all cancers, accounting for over 32,000 new cases per year with 12,800 deaths estimated to occur in 2020 in the United States.

Current Treatment Landscape and Unmet Need

First line therapy for NHL typically consists of multi-agent cytotoxic drugs in combination with the monoclonal antibody Rituxan. In younger patients with NHL who have good organ function, high dose chemotherapy followed by stem cell transplantation is often used. Patients often relapse, however, and over the last three years, several therapeutics have been approved in the United States for the treatment of patients with R/R NHL who have received prior therapies. These approved therapies include CD19 CAR T therapies tisagenlecleucel, axicabtagene ciloleucel and lisocabtagene maraleucel, CD19 antibody drug conjugate therapy polatuzumab vedotin, and CD19 antibody tafasitamab. Recently, pivotal trials with approved CD19 CAR T cells have been shown to be superior to standard of care approaches in patients in second line R/R NHL raising the possibility of broader impact for CD19 CAR T cells for patients with NHL.

Newly diagnosed CLL patients are often treated with targeted therapies such as BTK inhibitors, PIK3 inhibitors, BCL-2 inhibitors, or monoclonal antibodies targeting CD20, or CD52 in combination with chemotherapy. However, most patients treated with these regimens become refractory. Numerous drug candidates are in clinical development for the refractory patients, including next-generation kinase inhibitors and both autologous and allogeneic CAR T therapies targeting CD20 and CD19.

Cure rates for ALL patients have continued to increase over the last four decades, with pediatric ALL cure rates reaching greater than 80% in developed countries. This progress has been enabled by advances in combination chemotherapy, monitoring of minimal residual disease, expanded use of kinase inhibitors for Philadelphia chromosome–positive ALL, and the recent approval of Kymriah for R/R pediatric ALL. Adult patients fare much worse, however, with 5-year overall survival rates of approximately 20%, and there are still significant challenges managing R/R disease across all age groups. Multiple therapeutic candidates are in development for these R/R patients, including proteasome inhibitors, antimetabolites, JAK inhibitors, monoclonal antibodies, as well as autologous and allogeneic CAR T candidates.

First-line therapy for MM is induction and high-dose chemotherapy followed by a potential stem cell transplant. There are no curative treatment options for MM patients and the standard of care for R/R MM includes immunomodulary agents, proteasome inhibitors, monoclonal antibodies, cytotoxic agents, and hematopoietic stem cell transplant. Despite the recent advancement in available therapies for disease management, the 5-year overall survival rate remains approximately 50%. To this end, several groups are investigating autologous and allogeneic CAR T cell therapies for R/R MM. BCMA is among the most promising antigens used to target MM, with two approved BCMA CAR T therapies idecabtagene vicleucel, and ciltacabtagene autoleucel, as well as multiple late-stage clinical trials ongoing. Novel treatments with other mechanisms of action are also under development, including bispecific T cell engagers, next-gen antibodies, and antibody drug conjugates.

As highlighted above, recent therapeutic advances across R/R B cell malignancies have led to a variety of treatment options and better patient outcomes. In particular, autologous surface protein directed CAR T therapies have been highly effective in certain subsets of patients with R/R disease. However, not all patients have access to novel therapies, and even with them, many patients will ultimately relapse and succumb to their cancer, resulting in 100,000 deaths per year in the United States and Europe across these indications.

There are two outstanding challenges that have limited utilization of these CAR T therapies and their impact on broader groups of patients.

Relapse. The emerging post-approval data with tisagenlecleucel and axicabtagene ciloleucel have indicated that there are two broad categories of relapse. One involves loss of CD19 on malignant cells resulting in tumor escape. This finding was initially established for ALL and is the cause of relapse after CAR T cells for roughly half of patients. More recent data indicate that low antigen expression contributes to the lack of response in a meaningful number of patients with NHL. CD19 CAR T treatments have recently been tested in pivotal trials in earlier lines of therapy for NHL, which raises the possibility of more patients being treated with CD19 CAR T therapy who subsequently relapse due to CD19 loss.  Therefore, the development of CAR Ts targeting an alternate antigen beyond CD19 may be beneficial to address this growing unmet need. Data from several studies have shown that CD22 CAR T treatment has led to complete responses in NHL and ALL patients that have failed to reach a complete response or relapsed after treatment with a CD19 CAR T cell product. Additionally, dual targeting of CD19 and CD22 as the initial form of treatment may prevent this form of relapse, offering patients the potential for both a higher rate and longer duration of complete response. The second pattern of relapse relates to suboptimal CAR T cell functionality (poor expansion, poor persistence, T cell exhaustion) resulting in relapse of cancer that retains the targeted antigen. Unfortunately, re-infusion of the same CAR T cell product has had limited benefit

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in these patients although treatment with a different CAR T cell has demonstrated some promise in the context of ongoing clinical trials.

Manufacturing. The manufacturing process for a patient-specific product is complex, leading to limited access due to both infrastructure and cost considerations. As such, approved CAR T cell therapies have not been available to all patients in need of these highly effective therapies. Even for patients who are fortunate enough to have access, inevitable delays (often a month or more) in manufacturing may prevent use of therapy in patients with rapidly progressing malignancies. There are groups that are seeking to overcome access limitations by using healthy donor-derived, or allogeneic, CAR T cells instead of patient T cells. This approach yields off-the-shelf therapeutics that can be manufactured consistently, but questions remain around efficacy and durability, largely due to the inability to effectively control the host versus graft response with concern for eventual rejection of these products. As will be discussed in the subsection titled “—Our ex vivo Cell Engineering Pipeline,” our ex vivo allogeneic T cell program also seeks to address this host versus graft response.

T Cell Fusosome Program

Our T cell fusosome approach provides us with an opportunity to develop potential product candidates to expand access to CAR T cell therapy to many more patients in need. In addition, we believe the ability to deliver a payload encoding a CAR to a T cell inside the body has the potential to improve effectiveness over ex vivo manufactured CAR T cell products. Experience thus far has demonstrated that both CD8+ and CD4+ T cells contribute to the CAR T cell response. Thus, the fusosome programs we are developing will deliver the CAR gene using fusogens that directly and specifically target the CD8 co-receptor or the CD4 co-receptor on T cells following a single intravenous injection. These approaches could result in the generation of therapeutically active CAR T cells without the complexities and delays associated with the process of T cell collection and ex vivo manufacturing. Furthermore, the ex vivo expansion in the presence of high cytokine concentrations, while necessary for the manufacture of approved CAR T cell products, also contributes to marked changes in T cell quality that may not be therapeutically beneficial. We believe the generation of a CAR T cell within the natural physiological environment has the potential to improve the quality of the CAR T cell generated, potentially improving both efficacy and the side effect profile. Finally, the effectiveness of ex vivo manufactured CAR T cells is dependent on the administration of a lymphodepleting preparative regimen prior to infusion to facilitate expansion of the CAR T cell product, which can have meaningful adverse safety implications. We do not expect to need a lymphodepleting regimen prior to in vivo delivery of the CAR gene, as our goal is to expose our fusosomes to as many T cells in the body as possible.

Preclinical Data

Our preclinical data have demonstrated that fusosomes can deliver a genetic payload specifically and efficiently to human T cells in culture and in immunodeficient mice with intraperitoneally injected human peripheral blood mononuclear cells (PBMC) and fused with a single dose of a fusosome. The T cells can be categorized into functional subsets based on the expression pattern of cell surface molecules. CD3 is a protein expressed on all T cells, CD4 is expressed on the Helper T cells that primarily activate T and B cells to carry out their function, and CD8 is found on cytotoxic T cells that primarily kill cancerous or virally infected cells. We generated fusogens against these three cell-surface molecules and have demonstrated that we can deliver a marker gene to cells bearing these cell surface proteins in vitro.

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Fusogens Demonstrate the Ability to Target Multiple T Cell Subtypes

Fusosomes containing a gene that encodes a fluorescent marker protein called GFP (used to identify cells have been genetically modified by the fusogen) can efficiently and specifically deliver GFP to T cells in culture (CD8, CD4, and CD3). Expression of GFP is restricted to the population of T cells that express the specific T cell receptor targeted by the fusogen (CD8, CD4, or CD3).

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We have further established that fusosome delivery of a CD19 CAR gene to CD4 or CD8 T cells results in killing of human B cells and CD19+ leukemia cells in culture:

Delivery of CD19 CAR to CD4 T Cells Leads to in vitro Killing of B Cells and CD19+ Leukemia Cells

Demonstrates that the fusosome-generated CD4 CAR is functional and eradicates both nonmalignant B cells (CD19+/RFP-) as well as CD19+ leukemia cells expressing NALM6-RFP.

We have also validated, in vivo, the tumor-killing activity of CD8 T cells to which CD19 CAR has been delivered via a fusosome.

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Delivery of CD19 CAR to CD8 Cells Leads to in vivo Killing of Leukemia Cells in a Human Xenograft Mouse Model

Left panel: demonstrates activity of CD8 fusosome delivering CD19 CAR to human T cells in a murine leukemia xenograft model (Nalm-6). Note that when compared to untreated controls, fusosome delivery results in eradication of leukemia cells. Activated T cells were cultured with CD3/CD28 beads for 3 days prior to injection. CD8 fusosome delivering the CD19 CAR is effective regardless of activation status of T cells at time of injection. Right panel: represents quantification of luminescence (representing leukemic burden) from mice shown in left panel. Both cohorts of fusosome treated mice had significantly reduced tumor burden when compared to control as early as D10 (p≤.0001; One-way ANOVA Bonnferroni) Experimental note: Tumors injected on Day Zero, Donor T cells injected on Day Three and Fusosome injected on Day Four.

Using a human xenograft mouse model for leukemia (Nalm-6), we observed both prolonged survival and clearance of the leukemic cells. During the manufacture of autologous CAR Ts, cytokine signaling has to be activated in order to successfully produce functional CAR T cells. In our mouse experiments the CD8 fusosome was able to generate CD19 CAR cells just as effectively with activated as non-activated donor T cells.

Several of our human T cell fusogens cross-react on non-human primate (NHP) T cells including our lead candidate CD8 fusogen. We have used the fusogen to deliver a CD20 CAR into six NHPs (the CD20 CAR was chosen as the CD19 CAR to be used for our clinical programs does not cross-react with NHP B cells). As shown below, a single intravenous administration of our CD8 fusogen containing a CD20 CAR was associated with B cell depletion, including in the blood and in lymph nodes, in four out of six NHPs, occurring between day seven and fourteen. This result is consistent with reported observations that peak expansion of ex vivo manufactured CAR T cells typically occurs during the second week. Serum cytokines were transiently elevated at day seven in all fusosome-treated animals. CD20 CAR transgene (by vector copy number) and CD20 CAR mRNA could be detected in peripheral blood between days three to ten, and in the spleen at study termination. Importantly, there was no infusion-related toxicity or evidence for CAR-associated toxicity (cytokine release syndrome or neurotoxicity) other than the intended B cell depletion. The ability to deliver fusogen without toxicity and with evidence for activity in NHP are critical milestones for the program. In addition, the NHPs received no T cell activating agent or lymphodepletion. The latter potentially supports a path for the fusogen platform to enable delivery of CAR therapy without the lymphodepletion regimens used by existing ex vivo approaches, which have toxic side-effects. This and future NHP experiments will also provide important information on dosing parameters, durability of the effect, and provide pharmacokinetic, pharmacodynamic, and toxicology data.

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Delivery of CD20 CAR to CD8 Cells Causes B Cell Depletion in NHPs

Graph demonstrates activity of CD8 fusosome delivering CD20 CAR in NHPs. CD8 fusosome was delivered as a single intravenous infusion. B cell counts were quantified in peripheral blood using flow cytometry for CD20+ cells. Given expected NHP-to-NHP variability in baseline counts, data is represented as single lines per NHP and is shown as deviation from baseline level for each NHP at Day Fourteen (when maximal expansion of CAR T cells are expected). Significant B cell depletion is observed in four out of six NHPs. Note that no T cell activation was provided prior to fusosome delivery.

Development Plan and Key Next Steps

We are currently conducting experiments to validate the ability of a systemically administered fusosome to transduce T cells in an NHP and for these CAR T cells to deplete B cells. These NHP studies are also expected to inform preclinical pharmacology and toxicology.

As a next step, we intend to conduct our in-life GLP toxicology studies. While these studies are ongoing, we intend to scale our GMP manufacturing and finalize our initial development plan. We intend to submit an IND for SG295 to support clinical trials in patients with NHL in 2022. We continue to advance additional programs and plan to submit INDs over the next several years: SG242 in NHL, SG233 which delivers a CAR gene targeting CD22 and could be combined with targeting CD19, and our BCMA programs in MM.

Hepatocyte Fusosome Program

Numerous genetic metabolic diseases arise from gene defects that manifest in the liver and, in particular, in the hepatocyte. Additionally, hepatocytes can serve as protein manufacturing sites to deliver proteins to other cells in the body. Multiple modalities exist that enable delivery of genetic material to liver cells, including AAV and LNPs. However, these approaches have limitations, including non-integrating payloads, payload size, lack of cell specificity, and, in the case of AAV, immunogenicity. Our fusogen technology, which we expect will be able to deliver a payload specifically to hepatocytes in the liver, has the potential to address these limitations. Success with this hepatocyte-targeting technology may allow us to generate therapies for a number of genetic disorders. We are developing our lead product candidate, SG328, for ornithine transcarbamylase (OTC) deficiency, and we expect to submit an IND in the next several years.

Hepatocyte Targeting Capability

Targeting the hepatocyte with a fusogen can enable specific delivery of either integrating or non-integrating payloads. It can also be used to deliver the machinery of gene editing and gene modification tools to these cells, both with or without the inclusion of DNA to replace a mutated gene or gene fragment. Since we anticipate that hepatocytes transduced with fusosomes will harbor the novel genetic construct in their genome, all progeny of that cell will also have the genetic construct. Thus, the natural turnover and organ growth will not dilute the genetic construct, providing the potential for long-term expression and efficacy even when the

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fusosome is delivered during infancy, childhood, or when it is delivered to treat a disease where the disorder can cause rapid hepatocyte turnover.

We believe that success with an initial hepatocyte-targeted fusosome will meaningfully accelerate our future hepatocyte programs. Once a hepatocyte-targeting fusosome is established, our subsequent programs will require only substituting the relevant payload to correct for the defective gene in question, opening up the possibility to address multiple inherited liver diseases. Our initial focus is on monogenic diseases with clear biology linking the missing activity of a gene in hepatocytes to a disease outcome. According to the National Institute of Health, over 30 genetic disorders of the liver exist, impacting over 10,000 births annually around the world. Many of these disorders lead to death in the first few years or cause long term disabilities. Proof of concept within this set of initial diseases will enable expansion to other diseases, such as hemophilia, where we may be able to address an unmet need by providing a durable in vivo therapy in the hepatocyte.

Preclinical Data

Our ability to use our hepatocyte-targeting fusosomes in relevant animal models is limited by a lack of cross-species transduction. To address this, we first developed murine disease models and introduced the therapeutic payload utilizing a conventional lentivirus pseudotyped with VSV-G. The VSV-G fusogen targets the LDL receptor which is highly expressed in hepatocytes providing a potent in vivo delivery vehicle for hepatocytes. These models established proof of concept to treat these diseases through genomic integration of the corrected gene as well as transduction efficiency in the range that would be needed for efficacy. However, the LDL receptor is found on a significant number of other cell types resulting in extensive off-target transduction. We do not intend to move forward with this non-specific lentivirus construct, as its lack of specificity creates potential challenges in humans. However, it does provide a preclinical model system for us to understand the percentage of hepatocytes, as well as the expression level of the novel genetic material that are required for the intended therapeutic effect.

In parallel, we have developed and improved hepatocyte-specific fusosomes for high on target transduction efficiency (as measured by titer), with the goal of achieving potency comparable to or better than what we see with conventional lentivirus. Engineering of hepatocyte specificity is generated through the choice of target receptor selectively expressed in human hepatocytes. Through an iterative process focusing on multiple hepatocyte-selective cell surface protein targets, diverse binders, and protein engineering, we have developed constructs that have met our potency goals. We have tested these constructs in vivo in mouse models and shown that they can transduce human hepatocytes at levels comparable to conventional lentivirus with significantly lower frequency of off-target transduction. Furthermore, the transduction occurs in a dose-dependent manner.

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Improved Targeted Fusogens Exhibit High in vitro Transduction of Primary Human Hepatocytes (PHHs)

Improved hepatocyte-targeted fusosomes show levels of in vitro transduction similar to conventional lentivirus. Protein engineering of Fusogen 1b resulted in new sets of fusogens with significantly increased titer on PHHs. The most potent of these fusosomes approach the hepatocyte titer of conventional lentivirus.

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Improved Targeted Fusogens Can Transduce Hepatocytes in vivo in a Humanized Liver Mouse (FRG) at Comparable Levels to Conventional Lentivirus and in a Dose-Dependent Fashion

Hepatocyte-targeted fusosomes show levels of in vivo transduction similar to conventional lentivirus and dose dependence. Fusosomes were delivered by intravenous injection (tail vein) into humanized liver mice (FRG, or FAH- immunodeficient mice, repopulated with primary human hepatocytes). Dose for lentivirus was 1.4 10¹¹ TU/kg (# of transducing units per kilogram mouse body weight, tested on primary human hepatocytes). Highest dose for the hepatocyte-targeted fusosome was 1.1 10¹⁰ TU/kg (1X) and lower doses were at one-third (0.33X) and one-tenth (0.1X) of the highest dose. Liver cells were harvested from injected mice seven days after injection, separated into hepatocytes and non-parenchymal cells (non-hepatocytes) and analyzed for GFP expression and species (human or mouse).

Background on OTC Deficiency

OTC deficiency is the most common inherited disorder of the urea cycle, the process by which the body detoxifies ammonia and produces urea. It is the only urea cycle disorder that is X-linked, leading to more severe disease in males. OTC deficiency occurs in approximately 1 in 50,000 births, and there are approximately 10,000 patients worldwide. A deficiency of the OTC enzyme leads to accumulation of ammonia, which can lead to neurotoxicity manifesting early as vomiting and anorexia, before progressing to a progressive lethargy, seizures, intellectual impairment, coma, and death. The severity and age of onset of OTC deficiency can vary with the most severely affected, typically males, presenting shortly after birth. In this severe, neonatal onset of OTC deficiency, patients present with an overwhelming illness that rapidly progresses with up to 90% mortality rate despite advances in standard of care treatments. In less severely affected patients who present later in childhood or as adults, severe elevations of ammonia and resulting neurotoxicity still occur, primarily precipitated by an illness or excessive protein intake.

OTC Deficiency: Current Treatment Landscape and Unmet Need

The standard of care for patients with OTC deficiency includes a low protein diet, nutrient supplementation, and the use of ammonia scavengers such as benzoate, phenylacetate, or phenylbutyrate. Despite all of these measures, patients may still experience acute hyperammonemia crises particularly in the setting of increased protein catabolism that can be induced by viral illness or certain medications. These acute crises are treated with supportive care including kidney dialysis for rapid ammonia reduction. The frequency and duration of hyperammonemia crises has been directly linked to poor long-term outcomes and intellectual disability. The only curative therapy available is liver transplantation, which has become more common as surgical techniques and supportive care have improved over time. In those patients with severe, neonatal onset of OTC deficiency, liver transplantation is commonly performed before the age of five and, in some cases, can occur before one year of age.

In addition to the standard of care therapies noted above, therapies to replace the defective OTC gene have been pursued. Recent trials have primarily utilized AAVs to deliver a corrected OTC gene. While these viruses have to date been generally well tolerated, they are still associated with significant immunogenicity that can preclude use in the up to one third of patients with pre-existing antibodies to AAV and can lead to systemic symptoms, including elevated liver enzymes. Beyond the challenge of pre-existing antibodies, the primary drawback is the potential for transient efficacy as the gene replacement via AAV would not be expected to be

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permanent if replication of the target cell occurs. While the durability of an AAV delivered gene replacement for OTC deficiency depends on many factors, one of the key determinants is the rate of hepatocyte turnover. This is especially relevant in pediatric patients with growing livers and rapid cell turnover. This dilution of effect has been supported by animal studies where AAV delivered gene replacement was successful in adult animals but not successful in younger animals. The most severe form of OTC deficiency presents in the neonatal period and, if a donor is available, may be treated with liver transplantation, a permanent gene therapy that provides long lasting benefit to patients is required to address the greatest unmet need from OTC deficiency. Additionally, as hepatocytes continue to divide approximately once a year even in adults, a durable gene therapy would also be expected to provide an advantage even in adult patients where an AAV delivered gene therapy is likely to lose function over time.

We believe our approach of pursuing a permanent gene replacement therapy has the potential to improve morbidity, mortality, and quality of life even in the youngest, most severely ill patients.

Development Plan and Key Next Steps

We are conducting mouse studies to establish proof of concept and inform the dose profile of our lead hepatocyte fusosome. In the near term, we are seeking to finalize the hepatocyte-targeted fusosome candidate and begin GLP production. Dose and safety of our lead fusosome compositions for OTC will be further informed through NHP studies, and with success, we expect to submit an IND in the next several years. The hepatocytes of the liver are the one cell type readily accessible to competing technologies such as AAVs and LNPs. Each of these technologies has limitations overcome by the fusosome platform, but any future investment in therapeutics targeting hepatocytes will need to consider if these fusosome advantages are meaningful enough to patients to justify the investment. For example, we are currently evaluating whether our technology offers differentiated solutions to these liver-targeted gene therapies for genetic diseases such as Hemophilia and Alpha-1 antitrypsin deficiency.

HSC Fusosome Program

We are developing hematopoietic stem cell (HSC) targeted fusosomes, designed to target and repair genetic abnormalities underlying diseases such as sickle cell disease and beta-thalassemia (SG418), with the goal of achieving preclinical proof of concept as early as 2023.

Background on hemoglobinopathies

Devastating inherited hematologic disorders, including sickle cell disease, beta-thalassemia, and other hemoglobinopathies, are caused by a monogenic variant, and patients suffering from these diseases are candidates for in vivo cell engineering.

Sickle cell disease (SCD) is caused by a single point mutation in the beta globin gene (HbB). The resulting mutant form of the protein, referred to as HbS, is prone to aggregate into long, rigid molecules that deform red blood cells (RBCs) into a sickle shape, obstructing blood vessels and undergoing premature lysis. The consequences are severe pain (sickle cell crisis), tissue infarction, infection, anemia, stroke, and early death. SCD is the most common inherited blood disorder in the United States, affecting an estimated 100,000 individuals, and 134,000 individuals in Europe. The global prevalence of SCD is estimated to be approximately 4.4 million individuals and is most common among people of African, Middle Eastern and South Asian descent.

Beta-thalassemia is an inherited blood disorder caused by any one of over 200 mutations in HbB which results in reduced production of functional hemoglobin. Transfusion-dependent beta-thalassemia (TDBT) is the most severe form of this disease, often requiring multiple transfusions per year. Patients with TDBT suffer from failure to thrive, persistent infections, and life-threatening anemia. Frequent blood transfusions can lead to iron overload that then require iron chelation therapy, which itself is associated with significant toxicities, resulting in low levels of adherence. Even with frequent transfusions, patients with TDBT continue to suffer from failure to thrive, persistent infections, and life-threatening anemia.

The prevalence of beta-thalassemia globally is estimated to be 288,000. The total combined prevalence of beta-thalassemia in the United States and Europe is estimated to be approximately 19,000 patients, mostly in Europe. Of the patients currently treated in the United States and Europe, we believe approximately 50% and 10%, respectively, are transfusion dependent. Beta-thalassemia is especially prevalent in developing countries of Africa, South Asia, Southeast Asia, the Mediterranean region and the Middle East. Although historically prevalent in Mediterranean North Africa and South Asia, thalassemias are now encountered in other regions as a result of changing migration patterns. As such, there is a growing focus on developing new therapeutics aimed at improving quality of life for this significant unmet medical need.

Correction of the causal monogenic defects could potentially provide a one-time, curative treatment approach, rather than the current lifelong, multidisciplinary standard of care treatment.

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Current Treatment Landscape and Unmet Need

Despite its clear and well-known genetic nature, SCD remains underserved, with existing treatment strategies mostly supportive in nature. Allogeneic HSC transplantation (HSCT) is currently the only potentially curative therapy available. However, HSCT is limited by donor availability (approximately 15-30% worldwide).

Furthermore, chronic graft-versus-host disease is a major risk that contributes to the long-term morbidities associated with allogeneic HSCT. Otherwise, treatment options largely manage disease symptoms, including analgesia during crises, hydroxyurea, L-glutamine, and anti-infectives. Recently, two disease-modifying treatments were approved by the FDA, crizanlizumab and voxelotor. Crizanlizumab was approved for treating crises in SCD patients who are unresponsive to either hydroxyurea or L-glutamine. Voxelotor is an oral small molecule inhibitor of HbS polymerization, which compared to placebo, was associated with a reduction in acute crises. While these agents represent a meaningful advance in the treatment of SCD, they focus on supportive care and do not address the mutation in the gene that is the root cause of the disease.

As in SCD, there are limited treatment options available for TDBT, and those that exist are supportive in nature. Allogeneic HSCT is similarly potentially curative but is also limited by donor availability, the risk of GVHD, and other comorbidities that result from the procedure. Because of the need for recurring blood transfusions, patients require ongoing chelation therapy to avoid iron load from the transfusions and its associated organ damage. However, this treatment is burdensome and associated with significant toxicities, and consequently, has low adherence. Currently, there is only one FDA approved therapy for beta-thalassemia, luspatercept, which significantly reduces the frequency of blood transfusions needed. However, safety concerns remain with a possible increased risk for hypertension and thromboembolic events.

There are several therapies in development to treat diseases of the hematopoietic system that have demonstrated clinical proof of concept through ex vivo gene modification. These approaches directly address the genetic activity missing in SCD and TDBT by supplying a novel gene to the patient’s cell or by editing genome to enhance hemoglobin expression. The ex vivo process begins with the mobilization and removal of cells from the blood, a process known as leukapheresis. Next, these cells undergo a process to enrich for cells expressing an HSC marker, CD34. The enrichment of CD34 cells increases the percentage of long-lived HSCs, the key stem cell that is both persistent and can differentiate into all the cells of the blood. However, even under enrichment, long-lived HSCs make up less than 1% of all the CD34 cells. CD34+ cells are transduced with either a novel gene or genome editing complexes, each having a distinct therapeutic action. The cells are then cryopreserved and sent back to the patient. Before transplantation, the patients receive conditioning chemotherapy to prepare the body so that the gene-modified cells engraft after re-infusion. The current conditioning regimens are toxic, with significant risks and side effects, although less toxic regimens are in development. Key questions remain regarding durability and safety, particularly over time, for transplanting these ex vivo modified HSCs. Furthermore, manufacturing complexities, cost, and the complications from the myeloablative conditioning chemotherapy regimens remain significant obstacles to widespread adoption. There are multiple ongoing efforts to improve this approach by focusing on HSC procurement, transduction, gene-editing, milder conditioning regimens, and transplantation efficiency. We believe that the most meaningful opportunity to improve outcomes is to eliminate the complex ex vivo modification and transplantation steps by utilizing our fusogen technology to develop fusosomes that specifically target HSC and other key hematopoietic cells via in vivo delivery.

Our HSC Fusosome Approach

The use of an in vivo fusosome-based delivery system bypasses the requirement for ex vivo manufacturing and would require no conditioning chemotherapy. Without the manufacturing complexity and the requisite hospital stay for a patient who has undergone conditioning, as well as the concomitant costs and risks of each, in vivo therapies have the potential to meaningfully increase the number of patients that receive these therapies.

Targeting HSCs in vivo using fusogens requires identifying the appropriate cells and their corresponding cell surface receptors. HSCs have no single specific marker, but there are a number of cell surface proteins that are highly enriched on HSCs. Some of these markers also appear on erythrocytic, or red blood cell, progenitors, which may help establish both short-term and long-term efficacy. We have an ongoing program to discover fusogens with appropriate target specificity.

In parallel, we are establishing our capability to deliver different payloads utilizing the fusosome system. Our goal is to establish the appropriate cell specificity with the ability to utilize the appropriate gene modification system to achieve the right outcome for patients. With successful cell-specific targeting, we have an opportunity to deliver the therapeutic payload to the right cell without the need for complex ex vivo manufacturing or toxic conditioning chemotherapy.

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Development Plan and Key Next Steps

The next major milestones are to identify candidate fusogens for specific HSC targeting and fusosome compositions with relevant genome modification payloads. Our goal is to achieve preclinical proof of concept for SG418 as early as 2023 and submit an IND in the next several years.

SanaX

Despite the significant advances in the development of successful cell and gene therapies that have been made to date, there remain a number of fundamental limitations of existing technologies that prevent achieving the maximal breadth of application of these new therapeutic approaches. We wish to lead both the present and future of cell and gene therapy, and we are therefore committed to investing in research and other activities that will ensure a leadership position for the long-term. Towards this end, we have established SanaX as a distinct research arm.

In contrast to the industry’s traditional research activities which are focused primarily on near-term product development using existing technologies, SanaX is devoted to finding solutions to the limitations of today’s technology in order to expand the breadth of therapeutic opportunities. SanaX research efforts are aimed at making fundamental improvements to existing technologies and establishing new paradigms for gene and cell delivery that will ultimately lead to the development of completely new therapeutic modalities.

Truly novel technology development requires the unique ability to thoughtfully marry rigorous experimental science with specific technical goals. Often, fundamental biological problems must be understood in depth in order to define the pathway to a new technological and therapeutic capability. SanaX has established a unique physical and cultural environment with individuals that possess the requisite intellectual and technical capabilities essential for success. One characteristic of the SanaX research environment that we believe will be extremely valuable is a “nimbleness” that enables the team to immediately embrace new technical or scientific information and/or meet specific unanticipated therapeutic needs. In addition, several collaborative efforts with outside investigators possessing specific biological sector expertise have been established to enhance our internal efforts.

Current SanaX research activities are focused in several areas where we believe advances in technology are most critical. Some of these efforts include:

Dr. Mulligan, our Executive Vice-Chairman and Head of SanaX, directly oversees the SanaX research effort. SanaX maintains an independent research budget in order to ensure that these longer-term, disruptive priorities are not sacrificed for near-term needs. Once SanaX develops an understanding of how a technology can translate into the clinic, a program will move from SanaX into our internal R&D and manufacturing organization or partnered externally.

Manufacturing Strategy and Approach

While the field of cell and gene therapy has had a number of successes with innovative therapies, the challenges of manufacturing at industrial scale have limited access for patients in need. As was the case during the initial development of recombinant biologics, an improvement to our ability to characterize these products will be essential to increasing patient access. It is especially critical to have an in-depth understanding of the impact of manufacturing processes on the product quality attributes and resulting clinical performance of the product.

From inception, we have recognized the key role manufacturing plays in enabling the access of these innovative engineered cells as medicines. Two areas of particular focus are product analytical and biological characterization, leading to a better definition of critical product attributes, as well as process understanding, leading to better control the impact of process parameters on these critical product attributes.

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We have developed a manufacturing strategy that supports our vision of democratizing access with early investments in people, technology, and infrastructure:

To support our ex vivo and in vivo development pipeline, we are initially establishing three manufacturing platforms: viral vector, allogeneic T cells, and PSC-derived.

While the three manufacturing platforms are very different in terms of the manufacturing process and supply chain, they also share some common challenges and opportunities. For example, product characterization and analytical development are critical, and these capabilities are fungible across platforms. In addition, we are focusing on some of the key areas in each of the platforms to enable scaled manufacturing. For the viral vector platform, we are starting early in the research phase with suspension culture process in bioreactors similar to protein biologics to maximize process yield and batch to batch process robustness at scale. Transfer to these bioreactors later in development can complicate product comparability assessments. For the allogeneic T cell program, we are focusing on scaling the multiplex gene editing process and understanding of the impact of the variability of the starting material from healthy donors to on product quality. For stem-cell derived therapies, such as beta cells, cardiomyocytes, and glial progenitor cells, we are focusing on developing a scalable process and analytical technologies to characterize stability of the starting cells, end cell products, and critical product quality attributes.

To establish our manufacturing capability, we started with a non-GMP pilot plant for ex vivo and in vivo engineered cell platform processes with up to 200L bioreactor scale. This provides the infrastructure for process and technology development, technology transfer support, and production for non-GMP material such as GLP toxicology study material. In addition, we are taking a hybrid approach to establish our end-to-end supply chains for the three manufacturing platforms, leveraging a combination of internal manufacturing capability and external contract development and manufacturing organizations (CDMOs) for clinical supplies, in a staged manner:

Operating our own internal manufacturing facilities to complement our CDMO networks is a key to our strategy. Accordingly, in July 2021, we entered into a long-term lease to establish and operate our own GMP manufacturing facility to support our late-stage clinical development and early commercial product candidates across our product portfolio, including with the production of allogeneic T cells, viral vectors, and PSC-derived products. We believe that investing in an internal manufacturing facility will offer us a competitive advantage that will better position us to execute on our goal of ensuring broad and uninterrupted patient access to our therapies, including by allowing us to mitigate delays related to third-parties, including related to capacity-, personnel-, or production-related issues at our CDMOs; develop proprietary knowledge and product and process expertise we can utilize across our programs to create long-term value; and design a facility that can be optimized for and adaptable to our existing and future needs.

Competition

There are other companies that have stated that they are developing cell and gene therapies that may address oncology, diabetes, CNS disorders, and cardiovascular diseases. Some of these companies may have substantially greater financial and other resources than we have, such as larger research and development staff and well-established marketing and salesforces, or may operate in jurisdictions where lower standards of evidence are required to bring products to market. For example, we are aware that some of our competitors, including Novartis International AG, Gilead Sciences, Inc.,  Bristol-Myers Squibb Company, Novo Nordisk A/S, Johnson & Johnson, Allogene Therapeutics, Inc., CRISPR Therapeutics AG, Precision BioSciences, Inc., Caribou Biosciences, Inc., Fate Therapeutics, Inc., Century Therapeutics, Inc., bluebird bio, Inc., 2seventy bio, Inc., Orchard Therapeutics PLC, Aruvant Sciences, Inc., Sanofi S.A., Editas Medicine, Inc., Beam Therapeutics Inc. (Beam), ViaCyte Inc., Vertex Pharmaceuticals Incorporated, Eli Lilly and Company, Astellas Pharma Inc., and Bayer AG might be conducting large-scale clinical trials for therapies that could be competitive with our ex vivo and in vivo programs. Among companies pursuing ex vivo and in vivo cell engineering, we believe we are substantially differentiated by our robust intellectual property portfolio, extensive research, rigorous and objective approach, and multidisciplinary capabilities.

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Intellectual Property

We strive to protect and enhance the proprietary technology, inventions, and improvements that are commercially important to our business, including seeking, maintaining, and defending patent rights, whether developed internally or licensed from our collaborators or other third parties. Our policy is to seek to protect our proprietary position by, among other methods, filing patent applications in the United States and in jurisdictions outside of the United States related to our proprietary technology, inventions, improvements, and product candidates that are important to the development and implementation of our business. We also rely on trade secrets and know-how relating to our proprietary technology and product candidates, continuing innovation, and in-licensing opportunities to develop, strengthen, and maintain our proprietary position in the field of cell and gene therapy. We additionally plan to rely on data exclusivity, market exclusivity, and patent term extensions when available and, where applicable, plan to seek and rely on regulatory protection afforded through orphan drug designations. Our commercial success may depend in part on our ability to obtain and maintain patent and other proprietary protection for our technology, inventions, and improvements, preserve the confidentiality of our trade secrets, maintain our licenses to use intellectual property owned by third parties, defend and enforce our proprietary rights, including our patents, and operate without infringing on the valid and enforceable patents and other proprietary rights of third parties.

We have in-licensed and developed numerous patents and patent applications, which include claims directed to compositions, methods of use, processes, dosing, and formulations, and possess substantial know-how and trade secrets relating to the development and commercialization of our ex vivo and in vivo cell engineering platforms and related product candidates, including related manufacturing processes. As of February 2022, our in-licensed and owned patent portfolio consisted of approximately 41 licensed U.S. issued patents, approximately 78 licensed U.S. pending patent applications, and approximately 55 owned U.S. pending patent applications, as well as approximately 69 licensed patents issued in jurisdictions outside of the United States, approximately 326 licensed patent applications pending in jurisdictions outside of the United States (including approximately five licensed pending Patent Cooperation Treaty (PCT) applications), and approximately 42 owned patent applications pending in jurisdictions outside of the United States (including approximately 15 owned pending PCT applications) that, in many cases, are counterparts to the foregoing U.S. patents and patent applications. The patents and patent applications outside of the United States in our portfolio are held primarily in Europe, Canada, China, Japan, and Australia. For information related to our in-licensed intellectual property, see the subsection below titled “—Key Intellectual Property Agreements.”

For the product candidates and related manufacturing processes we develop and commercialize in the normal course of business, we intend to pursue, when possible, composition, method of use, process, dosing, and formulation patent protection. We may also pursue patent protection with respect to manufacturing, drug development processes and technology, and our technology platforms. When available to expand our exclusivity, our strategy is to obtain or license additional intellectual property related to current or contemplated development platforms, core elements of technology, and/or product candidates.

Individual patents extend for varying periods of time, depending upon the date of filing of the patent application, the date of patent issuance, and the legal term of patents in the countries in which they are obtained. Generally, patents issued for applications filed in the United States and in many jurisdictions worldwide have a term that extends to 20 years from the earliest nonprovisional filing date. In the United States, a patent’s term may be lengthened by patent term adjustment, which compensates a patentee for administrative delays by the Unites States Patent and Trademark Office (USPTO) in examining and granting a patent counterbalanced by delays on the part of a patentee, or may be shortened if a patent is terminally disclaimed over another patent. In addition, in certain instances, the patent term of a U.S. patent that covers an FDA-approved drug may also be eligible for patent terms extension, which recaptures a portion of the term effectively lost as a result of the testing and regulatory review periods required by FDA. The patent term extension period cannot be longer than five years, and the total patent term, including the extension, cannot exceed 14 years following FDA approval; however, there is no guarantee that the applicable authorities will agree with our assessment of whether such extensions should be granted, and, if granted, the length of such extensions. Similar provisions are available in Europe and other foreign jurisdictions to extend the term of a patent that covers an approved drug. Our patents issued as of February, 2022, have terms expected to expire on dates ranging from 2023 to 2040. If patents are issued on our patent applications pending as of February, 2022, the resulting patents are projected to expire on dates ranging from 2023 to 2043. However, the actual protection afforded by a patent varies on a product-by-product and country-to-country basis and depends upon many factors, including the type of patent, the scope of its coverage, the availability of regulatory-related extensions, the availability of legal remedies in a particular country, and the validity and enforceability of the patent.

In some instances, we submit patent applications directly with the USPTO as provisional patent applications. Provisional applications for patents were designed to provide a lower-cost first patent filing in the United States. Corresponding non-provisional patent applications must be filed not later than 12 months after the provisional application filing date. The corresponding non-provisional application benefits in that the priority date(s) of the patent application is/are the earlier provisional application filing date(s), and the patent term of the finally issued patent is calculated from the later non-provisional application filing date. This system allows us to obtain an early priority date, add material to the patent application(s) during the priority year, obtain a later start to the patent term, and to delay prosecution costs, which may be useful in the event that we decide not to pursue examination in an

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application. While we intend to timely file nonprovisional patent applications relating to our provisional patent applications, we cannot predict whether any such patent applications will result in the issuance of patents that provide us with any competitive advantage.

We file U.S. nonprovisional applications and PCT applications that claim the benefit of the priority date of earlier filed provisional applications, when applicable. The PCT system allows an applicant to file a single application within 12 months of the original priority date of the patent application and to designate all of the 153 PCT member states in which national patent applications can later be pursued based on the international patent application filed under the PCT. The PCT searching authority performs a patentability search and issues a non-binding patentability opinion which can be used to evaluate the chances of success for the national applications in foreign countries prior to having to incur the filing fees. Although a PCT application does not issue as a patent, it allows the applicant to seek protection in any of the member states through national-phase applications. At the end of the period of two and a half years from the first priority date of the patent application, separate patent applications can be pursued in any of the PCT member states either by direct national filing or in some cases by filing through a regional patent organization, such as the European Patent Organization. The PCT system delays expenses, allows a limited evaluation of the chances of success for national/regional patent applications, and enables substantial savings where applications are abandoned within the first two and a half years of filing.

For all patent applications, we determine claiming strategy on a case-by-case basis. We always consider the advice of counsel and our business model and needs. We file patents containing claims for protection of all useful applications of our proprietary technologies and any product candidates, as well as all new applications and/or uses we discover for existing technologies and product candidates, assuming these are strategically valuable. We continuously reassess the number and type of patent applications, as well as the pending and issued patent claims, to help ensure that maximum coverage and value are obtained for our inventions given existing patent office rules and regulations. Further, claims may be and typically are modified during patent prosecution to meet our intellectual property and business needs.

We recognize that the ability to obtain patent protection and the degree of such protection depends on a number of factors, including the extent of the prior art, the novelty and non-obviousness of the invention, and the ability to satisfy the enablement requirement of the patent laws. In addition, the coverage claimed in a patent application can be significantly reduced before the patent is issued, and its scope can be reinterpreted or further altered even after patent issuance. Consequently, we may not obtain or maintain adequate patent protection for any of our future product candidates or for our technology platform. We cannot predict whether the patent applications we are currently pursuing will issue as patents in any particular jurisdiction or whether the claims of any issued patents will provide sufficient proprietary protection from competitors. Any patents that we hold may be challenged, circumvented, or invalidated by third parties.

The patent positions of companies like ours are generally uncertain and involve complex legal and factual questions. No consistent policy regarding the scope of claims allowable in patents in the fields of cell and gene therapy has emerged in the United States. The patent situation outside of the United States is even more uncertain. Changes in either the patent laws or their interpretation in the United States and worldwide may diminish our ability to protect our inventions and enforce our intellectual property rights, and more generally could affect the value of our intellectual property. In particular, our ability to stop third parties from making, using, selling, offering to sell, or importing products that infringe our intellectual property will depend in part on our success in obtaining and enforcing patent claims that cover our technology, inventions, and improvements. With respect to both licensed and company-owned intellectual property, we cannot be sure that patents will be granted with respect to any of our pending patent applications or with respect to any patent applications filed by us in the future, nor can we be sure that any of our existing patents or any patents that may be granted to us in the future will be commercially useful in protecting our products and the methods used to manufacture those products. Moreover, even our issued patents do not guarantee us the right to practice our technology in relation to the commercialization of our products. The area of patent and other intellectual property rights in biotechnology is an evolving one with many risks and uncertainties, and third parties may have blocking patents that could be used to prevent us from commercializing our patented product candidates and practicing our proprietary technology. It is uncertain whether the issuance of any third-party patent would require us to alter our development or commercial strategies, products, or processes, obtain licenses, or cease certain activities. Our breach of any license agreements or our failure to obtain a license to proprietary rights required to develop or commercialize our future products may have a material adverse impact on us. If third parties prepare and file patent applications in the United States that also claim technology to which we have rights, we may have to participate in interference or derivation proceedings in the USPTO to determine priority of invention. Our issued patents and those that may issue in the future may be challenged, invalidated, or circumvented, which could limit our ability to stop competitors from marketing related products or limit the length of the term of patent protection that we may have for our product candidates. In addition, the rights granted under any issued patents may not provide us with protection or competitive advantages against competitors with similar technology. Furthermore, our competitors may independently develop similar technologies. For these reasons, we may have competition for our product candidates. Moreover, because of the extensive time required for development, testing, and regulatory review of a potential product candidate, it is possible that, before any particular product candidate can be commercialized, any related patent may expire or remain in force for only a short period following commercialization, thereby reducing any advantage of the patent. Our commercial success will also depend in part on not infringing upon the proprietary rights of third parties. Patent disputes are sometimes interwoven into other business disputes.

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As of February, 2022, our registered trademark portfolio contained approximately 25 registered trademarks and pending trademark applications, consisting of approximately two pending trademark applications in the United States, and approximately 13 registered trademarks and approximately ten pending trademark applications in the following countries through both national filings and under the Madrid Protocol: Australia, Canada, China, European Union, India, Japan, Republic of Korea, Singapore, and Switzerland.

We may also rely, in some circumstances, on confidential information, including trade secrets, to protect our technology. However, trade secrets are difficult to protect. We seek to protect our technology and product candidates, in part, by entering into confidentiality agreements with those who have access to our confidential information, including our employees, contractors, consultants, collaborators, and advisors. We also seek to preserve the integrity and confidentiality of our proprietary technology and processes by maintaining physical security of our premises and physical and electronic security of our information technology systems. Although we have confidence in these individuals, organizations, and systems, agreements or security measures may be breached, and we may not have adequate remedies for any breach. In addition, our trade secrets may otherwise become known or may be independently discovered by competitors. To the extent that our employees, contractors, consultants, collaborators, and advisors use intellectual property owned by others in their work for us, disputes may arise as to the rights in related or resulting know-how and inventions. For this and more comprehensive risks related to our proprietary technology, inventions, improvements, and products, see the subsection titled “Risk Factors —Risks Related to Intellectual Property and Information Technology.”

Key Intellectual Property Agreements

The following describes the key agreements by which we have acquired and maintained certain technology related to our ex vivo and in vivo cell engineering platforms and therapeutic programs.

Ex Vivo Cell Engineering Platform

License Agreement with Harvard

In March 2019, we entered into a license agreement (as amended, the Harvard Agreement) with the President and Fellows of Harvard College (Harvard), pursuant to which we obtained an exclusive, worldwide, sub-licensable license under certain patent rights controlled by Harvard to make, have made, use, offer for sale, sell, have sold and import (i) products and services covered by the patent rights and (ii) products containing stem cells, pluripotent cells or cells derived from stem cells, or pluripotent cells with certain specified genetic modifications ((i) and (ii) together, Harvard Products) or otherwise practice under and exploit the licensed patent rights, for the treatment of disease in humans or, in the case of certain other patent rights, for applications that involve the use of cells derived ex vivo from stem cells in the treatment of disease in humans. We also obtained a non-exclusive, sub-licensable license under certain other patent rights in the United States, and a non-exclusive, sub-licensable, worldwide license under know-how pertaining to the licensed patent rights, to make, have made, use, offer for sale, sell, have sold and import the Harvard Products, or otherwise practice under and exploit the licensed patent rights and know-how, for the treatment of disease in humans. We have the option to obtain such non-exclusive rights in additional jurisdictions if Harvard is successful in obtaining the right to grant such from the third-party co-owner of such patent rights. In October 2021, we entered into an amendment to the Harvard Agreement to include products containing primary cells with certain specified genetic modifications as Harvard Products. We utilize these license rights in our ex vivo cell engineering program relying on our hypoimmune technology.

We are obligated to use commercially reasonable efforts to develop Harvard Products in accordance with a written development plan, to market the Harvard Products following receipt of regulatory approval, and to achieve certain specified development and regulatory milestones within specified time periods, as such period may be extended, for at least two Harvard Products.

The licenses granted pursuant to the Harvard Agreement are subject to certain rights retained by Harvard and the rights of the U.S. government. The retained rights of Harvard pertain only to the ability of Harvard and other not-for-profit research organizations to conduct academic research and educational and scholarly activities and do not limit our ability to pursue our programs and product candidates. We agreed that we will not use any of the licensed patent rights for human germline modification, including intentionally modifying the DNA of human embryos or human reproductive cells.

Pursuant to the Harvard Agreement, we paid Harvard an upfront fee of $3.0 million, and we issued 2.2 million shares of our Series A-2 convertible preferred stock to Harvard as partial consideration for the licenses granted under the Harvard Agreement. Additionally, we paid $6.0 million to Harvard in connection with the issuance of shares of our Series B convertible preferred stock. We paid Harvard annual license maintenance fees of $25,000 for 2019, $50,000 for 2020, and $100,000 for each of 2021 and 2022, and we are required to pay annual license maintenance fees of $100,000 for each calendar year thereafter for the remainder of the term. We are required to pay Harvard up to an aggregate of $15.2 million per Harvard Product upon the achievement of certain pre-specified development and regulatory milestones for up to a total of five Harvard Products, or an aggregate total of $76.0 million for all five Harvard Products. These milestone payments would double if we undergo a change of control. We are also obligated to pay,

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on a product-by-product and country-by-country basis, royalties in the low single-digit percentage range on quarterly net sales of Harvard Products covered by licensed patent rights, and a lower single-digit percentage royalty on quarterly net sales of Harvard Products not covered by licensed patent rights. The royalty rates with respect to Harvard Products covered by licensed patent rights are also subject to specified and capped reductions for loss of market exclusivity and for payments owed to third parties with respect to patent rights which cover Harvard Products in the territory. We are also obligated to pay Harvard a percentage of certain sublicense income ranging from the high single-digit to low double-digit percentage range. We are obligated to pay up to $175.0 million in success payments based on increases in the per share fair value of our common stock at pre-specified valuation dates that include the one-year anniversary of the consummation of our IPO and periodically thereafter, the date of the consummation of a merger, an asset sale, or merger, or the sale of the majority of the shares held by our Series A convertible preferred stockholders, and the last day of the term of the success payments.

The Harvard Agreement will expire upon the expiration of the last-to-expire valid claim within the licensed patent rights or, if later, at the end of the final royalty term, which is determined on a Harvard Product-by- Harvard Product and country-by-country basis, and is the later of (i) the date on which the last valid claim within the licensed patent rights covering such Harvard Product in such country expires, (ii) expiry of regulatory exclusivity for such Harvard Product in such country, or (iii) ten years from the first commercial sale of such Harvard Product in such country, which we expect to occur in 2039. We also have the right to terminate the Harvard Agreement in its entirety for any reason upon 45 days’ prior written notice to Harvard. Either party may terminate the Harvard Agreement upon a material breach by the other party that is not cured within 60 days after receiving written notice thereof. Harvard may terminate the Harvard Agreement upon written notice in the event of our bankruptcy, insolvency, or similar proceedings. If we terminate the Harvard Agreement for convenience, our obligations to pay milestones and royalties with respect to Harvard Products that are not then covered by licensed patent rights will survive for the remainder for the applicable royalty term. If the Harvard Agreement is terminated for any reason, then sublicensees, other than our affiliates or sublicensees in material default or at fault for the termination, have the right to enter into a direct license with Harvard on substantially the same non-economic terms and on economic terms providing for the payment to Harvard of the consideration that would otherwise have been payable if the Harvard Agreement and the sublicense were not terminated.

License Agreement with UCSF

In January 2019, we entered into a license agreement (as amended, the UCSF Agreement) with The Regents of the University of California (The Regents) acting through its Office of Technology Management, University of California San Francisco (UCSF), pursuant to which we obtained an exclusive license to inventions related to immunoengineered pluripotent cells and derivatives claimed in U.S. and international patents and patent applications (UCSF Patent Rights) by The Regents. The license is to make, have made, use, sell, offer for sale and import licensed products that are covered by such UCSF Patent Rights, provide licensed services, practice licensed methods, and otherwise practice under the UCSF Patent Rights, for use in humans only, in the United States and other countries where The Regents is not prohibited by applicable law from granting such UCSF Patent Rights. We have the right to sublicense our rights granted under the UCSF Agreement to third parties subject to certain terms and conditions. We utilize these license rights in our ex vivo cell engineering platform program that relies on our hypoimmune technology.

We are obligated, directly or through affiliates or sub-licensees, to use commercially reasonable efforts to develop, manufacture, and sell one or more licensed products and licensed services and to bring one or more licensed products or licensed services to market. We are required to use commercially reasonable efforts to obtain all necessary governmental approvals in each country where licensed products or licensed services are manufactured, used, sold, offered for sale, or imported. We are required to spend at least $30.0 million towards research, development, and commercialization of licensed products within five years after the closing of our Series A-2 convertible preferred stock financing. In addition, we are required to achieve certain specified development and regulatory milestones within specified time periods. We have the ability to extend the time periods for achievement of development and regulatory milestones under certain terms set forth in the UCSF Agreement, including payment of extension fees. If we are unable to complete any of the specified milestones by the completion date, or extended completion date, for such milestone, then The Regents has the right and option to either terminate the Agreement, subject to our ability to cure the applicable breach, or convert our exclusive license to a non-exclusive license.

The Regents reserves and retains the right to make, use and practice the invention, and any related technology, and to make and use any products and to practice any process that is the subject of the UCSF Patent Rights (and to grant any of the foregoing rights to other educational and non-profit institutions) for educational and non-commercial research purposes, including publications and other communication of research results. This does not limit our ability to pursue our programs and product candidates.

Pursuant to the UCSF Agreement, we paid an upfront license fee of $100,000 to The Regents, and we issued The Regents 0.7 million shares of our Series A-2 convertible preferred stock. In addition, we entered into an amendment to the UCSF Agreement in December 2020, pursuant to which we issued 37,500 shares of our common stock to The Regents. We are required to pay license maintenance fees ranging from $10,000 on the first anniversary of the date of the UCSF Agreement to $40,000 on the sixth anniversary and continuing annually thereafter. This fee shall not be due if we are selling or exploiting licensed products or licensed

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services and paying an earned royalty to The Regents on net sales of such licensed products or licensed service. We are required to pay The Regents up to an aggregate of $2.45 million per licensed product upon the achievement of certain pre-specified development and regulatory milestones for the first five licensed products and half such amount for the second five licensed products, for an aggregate total of $18.4 million in development and regulatory milestone payments. Additionally, we are required to pay The Regents up to an aggregate of $0.5 million per licensed product upon the achievement of certain commercial milestones for the first five licensed products and half such amount for the second five licensed products, for an aggregate total of $3.75 million in commercial milestone payments. With respect to each licensed product, licensed service, or licensed method, we are obligated to pay, on a country-by-country basis, tiered royalties on net sales in the low single-digits. The royalty rates are subject to specified capped reductions for payments owed to unaffiliated third parties in consideration for patent rights, or patent rights together with know-how, in order to practice licensed methods or to make, have made, use sell, offer to sell, or import licensed products or licensed services. We are required to pay to The Regents a minimum annual royalty of $100,000 beginning with the year of the first sale of a licensed product or licensed service and ending upon the expiration of the last-to-expire UCSF Patent Right. This will be credited against any earned royalty due for the twelve-month period following which the minimum payment was made and pro-rated. We are also obligated to pay The Regents a percentage of certain non-royalty sublicense income ranging from the low double-digits to mid-twenties.

The UCSF Agreement will expire on expiration or abandonment of the last valid claims within the UCSF Patent Rights licensed thereunder, which we expect to occur in 2040. The Regents has the right to terminate the Agreement if we fail to cure or discontinue a material breach within 60 days of receiving a notice of default. We have the right to terminate the UCSF Agreement in its entirety or under certain UCSF Patent Rights on a country-by-country basis at any time by providing 60 days’ notice of termination to The Regents. The UCSF Agreement will automatically terminate in the event of our bankruptcy that is not dismissed within a specified time period. The Regents may immediately terminate the Agreement upon written notice if we file a non-defensive patent challenge. The termination of the UCSF Agreement will not relieve us of obligations to pay any fees, royalties, or other payments owed to The Regents at the time of such termination or expiration, including the right to receive earned royalties. If the UCSF Agreement is terminated for any reason, then, upon the request of any sublicensee, The Regents will enter into a direct license with such sublicensee on the same terms as the UCSF Agreement, taking into account any difference in license scope, territory, and duration of sublicense grant, provided that such sublicensee is not at the time of such termination in breach of its sublicensing agreement and is not at the time of such termination an opposing party in any legal proceeding against The Regents.

2019 Exclusive License Agreement with Washington University

In November 2019, we entered into a license agreement (the 2019 WU Agreement) with Washington University, pursuant to which we obtained an exclusive sublicensable, non-transferable, worldwide license under certain Washington University patent rights related to genetically engineered hypoimmunogenic stem cells to research, develop, make, have made, and sell products, the manufacture, use, sale or import of which by us or our sublicensees would, in the absence of the 2019 WU Agreement, infringe at least one valid claim of the licensed patent rights (WU Hypoimmune Products).

We are obligated to use commercially reasonable efforts to (i) develop, manufacture, promote and sell WU Hypoimmune Products and (ii) to achieve certain development, regulatory, and commercial diligence milestones within specified time periods. We have the ability to extend the time periods for achievement of such milestones under certain terms set forth in the 2019 WU Agreement, including payment of extension fees.

Washington University retains the right to make, have made, use, and import WU Hypoimmune Products in fields relating to diagnosis, prevention, and treatment of human diseases or disorders for research and educational purposes, including collaboration with other nonprofit entities, but excluding any commercial purposes, and such retained rights do not limit our ability to pursue our programs and product candidates. Washington University retains all rights not granted to us under the patents. In addition, the 2019 WU Agreement is subject to certain rights retained by the U.S. government, including the requirement that licensed products sold in the U.S. be substantially manufactured in the U.S.

Pursuant to the 2019 WU Agreement, we paid Washington University an upfront fee of $75,000. We are required to pay Washington University up to $100,000 in license maintenance fees on each anniversary of the 2019 WU Agreement’s effective date until the first commercial sale of a WU Hypoimmune Product. Upon the achievement of certain development and regulatory milestones, we are required to pay Washington University up to an aggregate of $2.0 million in milestone payments per WU Hypoimmune Product for the first three WU Hypoimmune Products, for an aggregate of $6 million in development and regulatory milestones. Additionally, upon the achievement of certain commercial milestones, we are required to pay Washington University up to an aggregate of $2.5 million in milestone payments per WU Hypoimmune Product for the first three WU Hypoimmune Products, for an aggregate of $7.5 million in commercial milestones. We are also obligated to pay royalties on annual net sales in the low single-digits, subject to a minimum amount of royalties payable in advance. The minimum annual royalty for the first anniversary of the effective date following the first commercial sale will be $100,000 and subsequently will increase up to a maximum minimum annual royalty of $750,000 on the fourth anniversary of the effective date following the first commercial sale. The royalties are payable

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provided there is at least one valid claim of licensed patent rights present in the country of manufacture or sale. The royalty rates are also subject to specified and capped reduction upon certain other events. Furthermore, we are obligated to pay Washington University a percentage of certain non-royalty sublicense income in the low double-digits.

The 2019 WU Agreement will expire upon the last-to-expire valid claim in the licensed patent rights, which we expect to occur in 2038. We also have the right to terminate the 2019 WU Agreement for any reason upon 90 days’ prior written notice to Washington University. Washington University may terminate the 2019 WU Agreement upon our material breach that is not cured within 30 days after receiving written notice thereof. In addition, Washington University may terminate the 2019 WU Agreement (i) upon 30 days’ written notice if we fail to achieve certain development, regulatory, or commercial diligence milestones and are unable to resolve Washington University’s concerns through good faith negotiations in accordance with the 2019 WU Agreement, (ii) upon our bankruptcy or insolvency, or (iii) if an order is made or a notice is issued convening a meeting of our stockholders to consider the passing of a resolution of our winding up or a resolution is passed for our winding up (in each case, other than for the purpose of amalgamation or reconstruction). If the 2019 WU Agreement terminates prior to the expiration of the last-to-expire licensed patent rights, we agree (i) to promptly discontinue the exportation of licensed products, (ii) to promptly discontinue the manufacture, sale, and distribution of the licensed products, (iii) to promptly destroy all licensed products in inventory, and (iv) not to manufacture, sell, or distribute licensed products until the expiration of the applicable last-to-expire licensed patent rights.

2020 License Agreement with Washington University

In September 2020, we entered into an exclusive license agreement (the 2020 WU Agreement) with Washington University for certain patent rights relating to the methods and compositions of generating cells of endodermal lineage and beta cells and uses thereof. Under the 2020 WU Agreement, we obtained an exclusive, worldwide, non-transferable, and royalty-bearing license under the patent rights to research, develop, make, have made, sell, offer for sale, have sold, use, have used, export, and import licensed products, the manufacture, use, sale or import of which by us or our sublicensees would, in the absence of the 2020 WU Agreement, infringe at least one valid claim of the licensed patent rights, solely in fields relating to diagnosis, prevention, and treatment of human diseases or disorders. We utilize these license rights in our ex vivo cell engineering platform program that relies on our hypoimmune technology, including our beta cell program.

Under the 2020 WU Agreement, we are obligated to use commercially reasonable efforts to (i) develop, manufacture, promote, and sell licensed products, and (ii)  achieve certain development, regulatory, and commercial diligence milestones within specified time periods. We have the ability to extend the time periods for achievement of such milestones under certain terms set forth in the 2020 WU Agreement, including payment of extension fees.

Washington University retains the right to use the licensed patent rights to make, have made, use, and import licensed products worldwide in fields relating to diagnosis, prevention, and treatment of human disease or disorders for research and educational purposes, including collaboration with other nonprofit entities, but expressly excluding any commercial purposes, and such retained rights do not limit our ability to pursue our programs and product candidates. In addition, the 2020 WU Agreement is subject to certain rights retained by the U.S. government, including the requirement that licensed products sold in the U.S. be substantially manufactured in the U.S.

Pursuant to the 2020 WU Agreement, we paid Washington University an upfront license issue fee of $150,000. We are required to pay annual license maintenance fees on each anniversary of the 2020 WU Agreement’s effective date until the first commercial sale of a licensed product. The license maintenance fee for the first and second anniversaries of the effective date will be $25,000 and subsequently will increase by $25,000 per two anniversaries up to a maximum annual license maintenance fee of $100,000. We are also required to pay Washington University up to an aggregate of $2.0 million upon the achievement of certain pre-specified development and regulatory milestones per licensed product for the first three licensed products under the 2020 WU Agreement, for an aggregate of $6 million in development and regulatory milestones. Additionally, we are required to pay Washington University, up to an aggregate of $4.5 million upon the achievement of certain pre-specified commercial milestones per licensed product for the first three licensed products under the 2020 WU Agreement, for an aggregate of $13.5 million in commercial milestones. We are also required to pay, for each licensed product made or sold by or for us worldwide, earned royalties on net sales of the licensed products in the low single-digits, with the royalty rate being subject to specified and capped reduction upon certain events. Under the 2020 WU Agreement, we are obligated to pay a minimum annual royalty commencing with the first anniversary of the effective date following the first commercial sale of the licensed product, which will be paid as an advance against the earned royalties paid to Washington University over the ensuing 12-month period. The minimum annual royalty for the first anniversary of the effective date following the first commercial sale will be $100,000 and subsequently will increase up to a maximum minimum annual royalty of $750,000 on the fourth anniversary of the effective date following the first commercial sale. The royalties are payable provided there is at least one valid claim of the licensed patent rights present in the country of manufacture or sale. Furthermore, we are obligated to pay Washington University a percentage of certain non-royalty sublicense income in the low double-digits.

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The 2020 WU Agreement will expire upon the last-to-expire valid claim under the licensed patent rights, which we expect to occur in 2038. We also have the right to terminate the 2020 WU Agreement for any reason upon 90 days’ prior written notice to Washington University. Washington University may terminate the 2020 WU Agreement upon our material breach that is not cured within 30 days after receiving written notice thereof. In addition, Washington University may terminate the 2020 WU Agreement (i) upon 30 days’ written notice if we fail to achieve certain development, regulatory, or commercial diligence milestones and are unable to resolve Washington University’s concerns through good faith negotiations in accordance with the 2020 WU Agreement, (ii) upon our bankruptcy or insolvency, or (iii) if an order is made or a notice is issued convening a meeting of our stockholders to consider the passing of a resolution of our winding up or a resolution is passed for our winding up (in each case, other than for the purpose of amalgamation or reconstruction). If the 2020 WU Agreement terminates prior to the expiration of the last-to-expire licensed patent rights, we agree (i) to promptly discontinue the exportation of licensed products, (ii) to promptly discontinue the manufacture, sale and distribution of the licensed products, (iii) to promptly destroy all licensed products in inventory, and (iv) not to manufacture, sell, or distribute licensed products until the expiration of the applicable last-to-expire licensed patent rights.

Oscine Acquisition

In September 2020, we acquired Oscine Corp. (Oscine), a privately-held early-stage biotechnology company pursing a glial progenitor ex vivo cell engineering program, in exchange for $8.5 million in cash, net of certain expenses. Of the total purchase price, $7.6 million was an upfront cash payment and $0.9 million was set aside (the Oscine Holdback Amount) to satisfy certain general representations and warranties as set forth in the stock purchase agreement. We had originally entered into a collaboration, license and option to purchase agreement with Oscine in November 2018. That agreement was terminated upon the closing of our acquisition of Oscine. As part of the Oscine acquisition, we also agreed to pay additional amounts of up to an aggregate of $225.8 million upon achievement of certain pre-specified development and commercial milestones, which we may pay in cash or in shares of our common stock, subject to certain conditions. As a result of the Oscine acquisition, we entered into, or obtained and amended, licenses to various technologies related to our glial progenitor ex vivo cell-based therapy program, including a license agreement with University of Rochester and a seed bank supply agreement with Hadasit Medical Research Services and Development Ltd.

License Agreement with University of Rochester

Effective as of the closing of the Oscine acquisition, we entered into an amended and restated exclusive license agreement (the Rochester Agreement) with the University of Rochester, which amended and restated a prior license agreement between Oscine and its affiliates and the University of Rochester and assigned Oscine’s rights and obligations in the license agreement to us. Under the Rochester Agreement, we obtained an exclusive, royalty-bearing, sublicensable, worldwide license under certain patents, and a non-exclusive, royalty-free license under know-how, to research, develop, import, make, have made, use, sell, offer to sell, commercialize, and otherwise exploit cell-based therapies for the treatment of human central nervous system disease and disorders. We utilize these license rights in our glial progenitor cell-based therapy program. We granted the University of Rochester a license to practice any patent rights that cover inventions in the field of cell-based therapies for human central nervous system diseases and disorders, which inventions are first conceived and reduced to practice solely by Dr. Steven Goldman acting in his capacity as our employee, or jointly with any of our employees reporting to Dr. Goldman, solely for Dr. Goldman or any of his lab members at the University of Rochester to practice such patent rights within Dr. Goldman’s laboratory at the University of Rochester for internal academic research purposes. University of Rochester granted us an automatic royalty-free non-exclusive license, and the option to obtain exclusive rights, to any patent rights or inventions conceived or reduced to practice by Dr. Goldman or members of his laboratory at the University of Rochester within a certain timeframe in connection with the internal academic research license that we granted to the University of Rochester. We are obligated to use commercially reasonable efforts to proceed with the commercial exploitation of the patents, to create a reasonable supply of licensed products to meet demand, and to adhere to a specified commercial development plan for development of stem cell therapy products, with pre-specified development milestones, including obtaining government approvals to market at least one licensed product, and to market such product within twelve months of receiving such approval.

The licenses granted pursuant to the Rochester Agreement are subject to certain rights retained by the University of Rochester and the rights of the U.S. government. The retained rights of the University of Rochester pertain only to its ability to conduct internal academic research other than clinical research and for teaching, education, and other non-commercial research activities, in publications related to its scientific research and findings, and for any other non-clinical and non-commercial purpose that is not inconsistent with the rights granted to us under the Rochester Agreement. These retained rights do not limit our ability to pursue our programs and product candidates.

Pursuant to the Rochester Agreement, we are obligated to pay to University of Rochester minimum annual royalties beginning in January 2023, the amount of which payments will be $20,000 in 2023, $50,000 in 2025, and will increase to $70,000 in 2028 and beyond. The minimum annual royalty payment is creditable against our obligation to pay tiered royalties on annual net sales in the low single-digits. The royalty rates are also subject to reduction upon certain other events. We are also required to pay University of Rochester up to an aggregate of $950,000 upon the achievement of certain pre-specified development and commercial milestones for

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each licensed product. In addition, we are required to pay a tiered mid-single digit to mid-double digit percentage of revenue arising from any sublicenses granted by us to third parties.

The Rochester Agreement will terminate on the last-to-expire of the licensed patents thereunder, which we expect to occur in 2038. We also have the right to terminate the Rochester Agreement in its entirety for any reason upon 90 days’ prior written notice to the University of Rochester. The University of Rochester may terminate the Rochester Agreement upon our material breach that is not cured within 30 days of receiving written notice thereof or immediately in the event of our bankruptcy. The University of Rochester may also terminate the Rochester Agreement, or at its sole discretion terminate the exclusivity of the license granted, upon our failure to meet the diligence obligations under and cure such failure within 90 days of our receipt of notice thereof, or such longer reasonable time determined by University of Rochester, at its discretion, and subject to a good faith negotiation mechanism included in the Rochester Agreement.

Supply Agreement with Hadasit Medical Research Services and Development Ltd.

In July 2018, Oscine Therapeutics (U.S.) Inc., an affiliate of Oscine, entered into a supply agreement (as amended, the Hadasit Agreement) with Hadasit Medical Research Services and Development Ltd. (Hadasit), pursuant to which Oscine obtained a quantity of seed bank cells and accompanying regulatory information on a non-exclusive basis for the sole purpose of developing, manufacturing, and selling cell therapy products for the treatment or prevention of central nervous system disorders in humans, which cell therapy products are derived using the Oscine proprietary differentiation technology from a certain human ESC line provided by Hadasit under the Hadasit Agreement. We utilize these cells and information in our glial progenitor cell program. Concurrently with our acquisition of Oscine in September 2020, the Hadasit Agreement was assigned by Oscine Therapeutics (U.S.) Inc. to Oscine. We amended the Hadasit Agreement effective as of the closing of the Oscine acquisition, and we subsequently assigned the Hadasit Agreement from Oscine to us.

Pursuant to the Hadasit Agreement, Oscine Therapeutics (U.S.) Inc. paid Hadasit an upfront fee of $24,000. We are required to pay Hadasit up to an aggregate of $1.1 million upon the achievement of certain development milestones for the first product. We are also obligated to pay tiered royalties in the low single digits on annual net sales of the relevant products worldwide, which obligation shall commence upon the first commercial sale of a relevant product and shall expire after 15 years on a product-by-product and country-by-country basis. The royalty rates are also subject to reduction upon certain other events.

The Hadasit Agreement will continue until terminated in accordance with its terms. Hadasit may terminate the Hadasit Agreement upon giving 30 days’ written notice if we fail to make any payment due thereunder and do not cure such failure within 30 days’ notice, or upon 60 days’ written notice if we cease to use the seed bank cells for the development and manufacture of our products, subject to our ability to dispute Hadasit’s claim and resolution of such dispute in accordance with a process set forth in the Hadasit Agreement. Either party may terminate the Hadasit Agreement upon a material breach by the other party that is not cured within 60 days after receiving written notice thereof, or upon giving written notice thereof, in the event of the other party’s bankruptcy.

Cytocardia Acquisition

In November 2019, we acquired Cytocardia, Inc. (Cytocardia), a privately-held early-stage biotechnology company developing ex vivo cell engineering programs focused on the replacement of damaged heart cells, in exchange for $8.0 million in cash, net of certain indebtedness and expenses, of which $6.8 million was an upfront cash payment, and $1.2 million was set aside (Cytocardia Holdback Amount) to satisfy certain general representations and warranties set forth in the stock purchase agreement. We also agreed to pay additional amounts of up to an aggregate of $75.0 million upon our achievement of certain pre-specified development milestones and up to an aggregate of $65.0 million in pre-specified commercial milestones. As a result of that transaction, we obtained licenses to various intellectual property and technologies, including intellectual property and technology related to our cardiomyocyte program that we rely on for development of our cardiac cell therapy product candidates. These included a license agreement with the University of Washington, as described below.

University of Washington

In October 2018, Cytocardia entered into an exclusive start-up license agreement (as amended, the UW Agreement) with the University of Washington (UW), pursuant to which Cytocardia obtained an exclusive license under certain patents relating to stem cell-derived cardiomyocytes and heart regeneration owned solely by UW or jointly by UW and the University of Cambridge, for which UW has the sole right to control the protection and licensing pursuant an inter-institutional agreement between UW and the University of Cambridge. We amended the UW Agreement in November 2019, concurrently with the closing of our acquisition of Cytocardia, and in July 2020 assigned the UW Agreement from Cytocardia to us. We further amended the UW Agreement in January 2021, February 2021, March 2021, April 2021, July 2021, September 2021, and October 2021 to add additional patent families to the scope of the license. The scope of the license is to make, have made, use, offer to sell, sell, offer to lease or lease, import, or otherwise

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offer to dispose of products worldwide (i) for any use, with respect to certain specified licensed patents, (ii) for the production of cardiomyocytes having an atrial or ventricular phenotype, with respect to other specified licensed patents, and (iii) heart regeneration therapy, with respect to other specified licensed patents. Additionally, UW granted us a non-exclusive, worldwide license to use certain related know-how, clinical trial information, and program materials. We may sublicense the exclusively licensed rights under the UW Agreement. We may also sublicense the non-exclusively licensed rights, but only for the purpose of using them in conjunction with exclusively licensed rights. We utilize intellectual property in our cardiomyocyte program. For a period of 12 months after the effective date of the UW Agreement, UW agreed to provide reasonable written notice to us of any improvements to the licensed patents upon notice to UW.

We have the option to add such improvements to the licensed patents. Pursuant to the UW Agreement, we are required to use commercially reasonable efforts to commercialize the licensed rights and to make and sell licensed products as soon as practicable and to maximize sales thereof. We are also obligated to achieve specified development, regulatory, and commercial milestones within specified time periods.

Inventions covered in the licensed patents have arisen, in whole or in part, from federally supported research by the U.S. federal government, and the licenses granted pursuant to the UW Agreement are subject to certain rights of the U.S. government. UW has retained for itself as well as for Cambridge University and for any other not-for-profit academic research institution, an irrevocable, nonexclusive right to practice the licensed rights for academic research and instructional or any other academic or non-commercial purpose. UW has retained for itself an irrevocable, nonexclusive license to practice licensed rights for clinical purposes. Cambridge University has also retained for itself an irrevocable, nonexclusive license to practice certain rights co-owned with UW for clinical purposes.

Pursuant to the UW Agreement, we will pay to UW a low single-digit royalty on net sales of products, with the royalty rate being subject to specified and capped reduction upon certain events. We will pay minimum annual fees for the term of the UW Agreement, to be creditable against running royalty payments for the preceding calendar year on a noncumulative basis. These minimum annual fees are due following the second anniversary of the effective date of the UW Agreement and continue during the term of the UW Agreement, ranging from $5,000 up to $50,000 for the years following the second anniversary of the first commercial sale of an FDA-approved licensed product. We will also pay to UW non-cumulative, non-creditable, and non-refundable development milestone payments of up to $175,000 and commercial milestone payments of up to $700,000 for the first licensed product to achieve each applicable milestone event. Furthermore, pursuant to the UW Agreement, we are obligated to pay UW a percentage of certain non-royalty sublicense income ranging from the low single-digits to middle double-digits, depending on the stage of development of our licensed products at the time of execution of the sublicense agreement.

The UW Agreement will expire, without further action by the parties, when all valid claims of the licensed patents have expired, and we have sold all licensed products manufactured prior to the expiration of such valid claims, which we expect to occur in 2040. UW may terminate the UW Agreement if we (i) permanently cease operations, (ii) voluntarily file or have filed against us a petition under applicable bankruptcy or insolvency laws that we fail to have released within 30 days after filing, (iii) propose any dissolution, composition, or financial reorganization with creditors, or if a receiver, trustee, custodian, or similar agent is appointed, (iv) make a general assignment for the benefit of creditors, (v)  challenge the validity of the licensed patents, or (vi)  breach our material obligations under the UW Agreement and do not cure such breach within 60 days. We may terminate the UW Agreement at any time by delivering to UW a written notice of termination at least 60 days prior to the effective date of termination. In addition, we may propose to terminate certain of our licensed rights under the UW Agreement by delivering to UW a written notice of termination accompanied by a proposed written amendment to the UW Agreement at least 60 days prior to the effective date of termination of such licensed rights.

Non-Exclusive License and Development Agreement with FUJIFILM Cellular Dynamics, Inc.

In February 2021, we entered into a non-exclusive license and development agreement (as amended, the FCDI Agreement) with FUJIFILM Cellular Dynamics, Inc. (FCDI), pursuant to which we obtained non-exclusive rights and a license under certain intellectual property rights controlled by FCDI (including intellectual property rights owned by FCDI and patent rights in-licensed from the Wisconsin Alumni Research Foundation) to research, develop, make, have made, use, have used, sell, offer for sale, import, and otherwise exploit human cell therapy products derived from certain iPSC lines for the treatment or prevention of certain diseases. We anticipate utilizing these intellectual property rights and iPSC lines in certain of our ex vivo cell engineering programs.

Pursuant to the FCDI Agreement, we agreed to pay FCDI an upfront fee of $1.0 million, annual license maintenance fees, and license fees of up to $500,000 per indication for one certain cell type or up to $350,000 per indication for certain other cell types. We are required to pay FCDI up to an aggregate of $28.5 million per indication upon the achievement of certain pre-specified development and regulatory milestones for up to a total of three indications and up to an aggregate of $14.25 million in pre-specified development and regulatory milestones for each additional indication. We are also required to pay up to an aggregate of $8.8 million per product upon the achievement of certain pre-specified commercial milestones. In addition, we are obligated to pay royalties on

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annual net sales of the relevant products worldwide in the low- to mid-single digits, which obligation shall commence upon the first commercial sale of a relevant product and shall expire after 15 years on a product-by-product and country-by-country basis. The royalty rates are also subject to reduction upon certain other events.

The FCDI Agreement will continue until terminated in accordance with its terms. FCDI may terminate the FCDI Agreement upon giving written notice if we fail to make any payment due or upon our material breach, subject, in each case, to our ability to dispute or cure such breach. We may also terminate the FCDI Agreement for convenience upon prior written notice, and either party may terminate upon giving written notice in the event of the other party’s bankruptcy.

License Agreement with Beam

In October 2021, we entered into an option and license agreement (the Beam Agreement) with Beam, pursuant to which Beam granted us a non-exclusive license to use Beam’s proprietary CRISPR Cas12b nuclease editing technology for a specified number of gene editing targets to research, develop and commercialize engineered cell therapy products that (i) are directed to certain antigen targets, with respect to our allogeneic T cell programs, or (ii) comprise certain human cell types, with respect to our stem cell-derived programs. We are permitted to use the CRISPR Cas12b system to modify or introduce, ex vivo, selected genetic sequences with respect to licensed products.  The Beam Agreement excludes any rights to base editing using the CRISPR Cas12b system.

Pursuant to the Beam Agreement, we have the option, for a period of one year from the effective date of the Beam Agreement, to select additional antigen targets, with respect to our allogeneic T cell programs, or human cell types, with respect to our stem cell-derived programs, in each case, upon our payment of an option payment of $10 million per antigen target or cell type. In addition, we may, for a period of three years from the effective date of the Beam Agreement, (i) elect to replace an antigen target, with respect to our allogeneic T cell programs, or human cell type, with respect to our stem cell-derived programs (Replacement Right) previously selected by us, and (ii) select new gene editing targets, or replace gene editing targets previously selected by us, with respect to any licensed product (Gene Nomination Right). In each case, our rights with respect to its exercise of the option, Replacement Right or Gene Nomination Right are subject to certain limitations.

Pursuant to the Beam Agreement, we paid Beam an upfront payment of $50 million. Additionally, with respect to each licensed product, we will be obligated to pay to Beam up to $65 million in specified developmental and commercial milestone payments. We will also be obligated to pay to Beam an aggregate royalty, including any royalty owed by Beam to its licensor, on a licensed product-by-licensed product and country-by-country basis, in the low- to mid-single digits, subject to reduction in certain circumstances, on net sales of each licensed product until the latest of (i) the expiration of certain patents covering such licensed product in the applicable country, (ii) the date on which any applicable regulatory exclusivity, including orphan drug, new chemical entity, data or pediatric exclusivity, with respect to such licensed product expires in such country, or (iii) the 10th anniversary of the first commercial sale of such licensed product in such country.

Unless earlier terminated by either party, the Beam Agreement will expire on a licensed product-by-licensed product and country-by-country basis upon the expiration of our payment obligations with respect to each licensed product thereunder. We may terminate the Beam Agreement in its entirety or on an antigen target-by-antigen target basis (with respect to licensed product applicable to our allogeneic T cell programs), on a cell type-by-cell type basis (with respect to licensed product applicable to our stem cell-derived programs), or on a licensed product-by-licensed product basis, in each case, upon (i) 90 days’ advance written notice, if such notice is provided prior to the first commercial sale of a licensed product, or (ii) 180 days’ advance written notice, if such notice is provided after the first commercial sale of a licensed product. Either party may terminate the Beam Agreement with written notice for the other party’s material breach if such breaching party fails to timely cure the breach with respect to the country in which such material breach relates. Beam may terminate the Beam Agreement in its entirety if we or our affiliates or sublicensees commence a legal action challenging the validity, patentability, enforceability, or scope of any of the patent rights licensed to us thereunder. Either party also may terminate the Beam Agreement in its entirety upon certain insolvency events involving the other party.

License Agreement with the NIH

In January 2022, we entered into a patent license agreement (the NIH Agreement) with the U.S. Department of Health and Human Services, as represented by The National Cancer Institute, an institute of the National Institutes of Health (the NIH), pursuant to which the NIH granted to us an exclusive, worldwide, commercial license under certain patent rights related to certain fully-human anti-CD22 binders and CD22 CAR constructs comprising such binders for use in certain in vivo gene therapy and ex vivo allogeneic CAR T cell applications for B cell malignancies. The license grant is subject to customary statutory requirements and reserved rights as required under federal law and NIH requirements. We have the right to grant sublicenses under the licensed patent rights with the NIH’s prior consent.

Pursuant to the NIH Agreement, we paid to the NIH an upfront payment of $1.0 million. Additionally, we will be obligated to pay to the NIH (i) up to an aggregate of $9.6 million in specified regulatory, developmental, and commercial milestone payments

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with respect to each product developed through exploitation of the licensed patent rights, and (ii) a payment of $1,000,000 upon the assignment of the NIH Agreement to an affiliate upon a change of control. In addition, we are obligated to pay to the NIH (i) a royalty on net sales of licensed products in the low-single digits, subject to reduction in certain circumstances, and subject to certain annual minimum royalty payments, and (ii) a percentage, ranging from the mid-single digits to mid-teens, of revenues from sublicensing arrangements. Additionally, if we are granted a priority review voucher by the U.S. Food and Drug Administration with respect to a licensed product, we will be obligated to pay to the NIH the greater of (i) $5,000,000 or (ii) a percentage in the mid-single digits of any consideration received for the sale, transfer, or lease of such priority review voucher. We are also obligated to pay to the NIH a percentage in the low-single digits of the consideration we receive for any assignment of the NIH Agreement to a non-affiliate.

We are obligated to use commercially reasonable efforts to exploit, and make publicly available, inventions developed by the exploitation of the licensed patent rights, including licensed products.

Unless earlier terminated by either party, the NIH Agreement will terminate upon expiration of the last-to-expire valid claim in the licensed patent rights. The NIH may terminate the Agreement with written notice for our material breach if we fail to timely cure such breach or upon certain insolvency events involving us. In addition, the NIH may terminate or modify the NIH Agreement, at its option, if the NIH determines that such termination or modification is necessary to meet the requirements for public use specified by federal regulations issued after the effective date of the NIH Agreement, and we do not reasonably and timely satisfy these requirements. We may terminate the NIH Agreement or any licenses in any country or territory upon 60 days’ prior written notice.

In Vivo Cell Engineering Platform

Cobalt Acquisition

In February 2019, we acquired all of the outstanding equity interests in Cobalt Biomedicine, Inc. (Cobalt), a privately-held early-stage biotechnology company founded by a Flagship Labs innovation team within Flagship Pioneering led by Dr. Geoffrey von Maltzahn that was developing a fusogen technology platform to specifically and consistently deliver diverse payloads—including DNA, RNA, and proteins—to targeted cells in vivo, in consideration of the issuance of 36.4 million shares of our Series A-2 convertible preferred stock, valued at $136.0 million. Of the 36.4 million shares of Series A-2 convertible preferred stock issued, 12.1 million shares were contingent on the achievement of a pre-specified development milestone, which was achieved in July 2019. We also agreed to pay contingent consideration of up to an aggregate of $500.0 million upon our achievement of certain pre-specified development milestones and a success payment of up to $500.0 million (the Cobalt Success Payment), which we may elect to pay in cash or in stock. The payout of the Cobalt Success Payment will only be paid if, at pre-determined valuation measurement dates, our market capitalization equals or exceeds $8.1 billion, and we are advancing a program based on the fusogen technology in a clinical trial pursuant to an IND, or have filed for, or received approval for, a BLA or NDA with respect to a program based on the fusogen technology. The valuation measurement dates for the Cobalt Success Payments are triggered by certain pre-determined valuation measurement dates, including the closing of our IPO and periodically thereafter. In addition to our IPO, a valuation measurement date would be triggered upon a change of control if at least one of our programs based on the fusogen technology is the subject of an active research program at the time of such change of control. As a result of the Cobalt transaction, we obtained licenses to various technologies and intellectual property rights that relate to the development of our fusogen technology and related fusosome programs, including exclusive license agreements with Flagship Pioneering Innovations V, Inc. (Flagship) and La Societe Pulsalys (Pulsalys), as well as several exclusive options to enter into exclusive license agreements, including one such option with The Regents of the University of California acting through The Technology Development Group of the University of California, Los Angeles (UCLA), with whom we later entered into an exclusive license agreement.

License Agreement with Flagship

In February 2016, Cobalt entered into an agreement (as amended, the Flagship Agreement), with Flagship, pursuant to which (i) Cobalt irrevocably and unconditionally assigned to Flagship all of its right, title and interest in and to certain foundational intellectual property developed by Flagship Pioneering, Inc. (Flagship Management) during the exploration and/or proto-company phase of Cobalt prior to its spin-out from Flagship (the Managerial Agreement), as set forth in the Flagship Agreement (such foundational intellectual property, the Fusogen Foundational IP), and (ii) Cobalt obtained an exclusive, worldwide, royalty-bearing, sublicensable, transferable license from Flagship under such Fusogen Foundational IP to develop, manufacture, and commercialize any product or process or component thereof, the development, manufacturing and commercialization of which would infringe at least one valid claim of Fusogen Foundational IP absent the license granted under the Flagship Agreement (Fusogen Products) in the field of human therapeutics during the term of the Flagship Agreement. In addition, Flagship irrevocably and unconditionally assigned to Cobalt all of its right, title and interest in and to any and all patents claiming any inventions conceived (i) solely by Flagship Management or jointly by Flagship Management and Cobalt, (ii) after Cobalt’s spinout from Flagship, and (iii) as a result of activities conducted pursuant the Managerial Agreement or other participation of Flagship Management in Cobalt’s affairs, but excluding Fusogen Foundational IP. We utilize the rights granted by Flagship under the Flagship Agreement in our fusogen platform and related

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therapeutic product candidates. The license granted to Fusogen Foundational IP is contingent upon Cobalt’s compliance with its obligations under the Flagship Agreement. Under the Flagship Agreement, Cobalt also granted Flagship a non-exclusive, worldwide, royalty-free, fully paid, sublicensable license to practice the Fusogen Foundational IP within the field of human therapeutics solely to perform under the Managerial Agreement.

Pursuant to the Flagship Agreement, Cobalt is obligated to pay, on a Fusogen Product-by-Fusogen Product and jurisdiction-by-jurisdiction basis, royalties in the low single-digit percentage on net sales of Fusogen Products. The Flagship Agreement will terminate on the last-to-expire royalty term, which is determined on a Fusogen Product-by-Fusogen Product and jurisdiction-by-jurisdiction basis, and is the earlier of (i) the expiration of the last valid claim of any Fusogen Foundational IP covering such Fusogen Product or (ii) the date on which the last applicable additional milestone payment has been made in accordance with that certain merger agreement under which we acquired Cobalt, which we expect to be in 2039. Upon expiration of the royalty term with respect to a Fusogen Product in any jurisdiction and payment in full of all amounts owed under the Flagship Agreement for such Fusogen Product, the license granted to us will automatically convert into a non-exclusive, fully paid-up license for such Fusogen Product in such jurisdiction. We have the right to terminate the Flagship Agreement in its entirety for convenience upon 60 days of written notice. Either party may terminate the Flagship Agreement upon a material breach by the other party that is not cured within 30 days after receiving written notice. Also, Flagship may terminate the Flagship Agreement (i) upon 30 days’ written notice if we cease to carry on our business with respect to the rights granted in the Flagship Agreement, (ii) upon written notice if we experience an event of bankruptcy, or (iii) immediately upon written notice if we challenge the validity, patentability, or enforceability of any Fusogen Foundational IP or participate in any such challenge.

Sublicense Agreement with Pulsalys

In August 2018, Cobalt entered into an exclusive sublicense agreement (as amended, the Pulsalys Agreement), with Pulsalys, which Cobalt assigned to us in May 2020, and pursuant to which we obtained an exclusive, worldwide, sublicensable sublicense from Pulsalys of the exclusive license granted to Pulsalys by École normale supérieure de Lyon (ENS Lyon) on behalf of itself and Institut National de la Santé et de la Recherche Médicale (Inserm), Centre National de la Recherche Scientifique (CNRS) and Université Claude Bernard Lyon 1 (collectively, the Co-Owners) under certain patent rights relating to methods to selectively modulate the activity of distinct subtypes of immune cells using engineered virus-like particles. In addition, Pulsalys granted us the first right to negotiate an exclusive license to patent rights covering certain improvements to the licensed patent rights that are owned or held by Pulsalys. We utilize the rights granted under the Pulsalys Agreement in our in vivo fusogenic platform and related fusosome programs. Under the Pulsalys Agreement, we are obligated to use commercially reasonable efforts to develop and commercialize licensed products, which efforts we can demonstrate by the achievement of the following diligence milestones: (i) incurring a minimum annual spend of $1.0 million for each of the five years after the effective date of the Pulsalys Agreement, and (ii) submitting an IND within five years of the effective date of the Pulsalys Agreement. Under the Pulsalys Agreement, the Co-Owners will retain the right to practice the licensed patent rights for non-commercial research purposes, alone or in collaboration with third parties.

Pursuant to the Pulsalys Agreement, Cobalt paid Pulsalys an upfront fee of 18,000 EUR. We are required to pay an annual license maintenance fee of 18,000 EUR until the first commercial sale of a licensed product. We are also required to pay Pulsalys up to an aggregate of 575,000 EUR upon the achievement of certain clinical and regulatory milestones for each of the first three distinct licensed products. In addition, we are obligated to pay an annual royalty in the low single-digits on net sales of the licensed products, with the royalty rate being subject to reduction upon certain events. Lastly, we are obligated to pay percentage annual fees on certain sublicense income in the low single-digits .

The Pulsalys Agreement will terminate on a country-by-country and licensed product-by-licensed product basis upon the expiration of the last-to-expire valid claim within the licensed patent rights covering the making, using, sale, and import of such licensed product in such country or any patent term extension or supplementary protection certificate thereof covering the sale of such licensed product in such country, which we expect to occur in 2037. We also have the right to terminate the Pulsalys Agreement in its entirety upon notice if we determine, in our sole discretion, that continued pursuit of development of the licensed patent rights is not feasible or desirable in the context of (i) the resources available to us or due to external factors such as competition, market forces, or access or license to other reasonably useful intellectual property, or (ii) a change of direction of our business focus. Either party may terminate the Pulsalys Agreement upon a material breach by the other party that is not cured within 90 days after receiving written notice thereof. Pulsalys may terminate the Pulsalys Agreement (i) in full in the case of we undergo a cessation of business, dissolution or voluntary liquidation, or (ii) in full or in part (x) if we challenge the validity of the licensed patents, provided that such termination will be with respect to the claims within the licensed patents that are the subject of such challenge, or (y)  if we fail to achieve the diligence milestones, and if the parties have not extended such milestones after good faith negotiations, and subject to our ability to cure such failure within 90 days after notice of the same.

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License Agreement with UCLA

In March 2019, we entered into a license agreement (as amended, the UCLA Agreement) with UCLA, upon the exercise of an option originally granted by UCLA to Cobalt in April 2018. Under the UCLA Agreement, UCLA granted us an exclusive, sublicensable, transferable (subject to certain conditions) license in the licensed territory in the field of human therapeutics under certain patent rights relating to certain virus envelope pseudotyped lentiviruses and methods of their use to (i) research, make, have made, use, sell, offer for sale, have sold and import licensed products and (ii) practice licensed methods for the purposes of researching, manufacturing, and using licensed products, but not to perform services for a fee. The licensed territory under the UCLA Agreement is all countries of the world in which the licensed patent rights have or will be filed. UCLA agreed not to grant any rights under the licensed patents regarding licensed methods to third parties without first offering us an opportunity to remove the restrictions regarding the use of licensed methods to perform services for a fee. In addition, we agreed not to commercialize any licensed product that is not administered directly to a patient for therapeutic purposes without first negotiating with UCLA for possible development milestones, royalties, or other payments applicable to such licensed products. We utilize the rights granted under the UCLA Agreement in our in vivo fusogenic platform and related fusosome programs. We are obligated to use commercially reasonable and diligent efforts to (i) develop licensed products, (ii) market licensed products, and (ii) manufacture and sell licensed products in quantities sufficient to meet market demands. We are also required to satisfy certain development and commercial milestones with respect to at least one licensed product that is administered directly to a patient for therapeutic purposes.

The license granted pursuant to the UCLA Agreement is subject to certain rights retained by the California Institute for Regenerative Medicine (CIRM) and the U.S. government, including a non-exclusive, royalty-free license granted to the U.S. government in accordance with 35 U.S.C. §200-212. If CIRM exercises its rights under Title 17, California Code of Regulations, Section 100600, and the scope of our exclusive license under the UCLA Agreement is impacted, then our financial obligations therein will be reduced by 50%. Otherwise, rights retained by CIRM do not limit our ability to pursue our programs and product candidates. In addition, UCLA retains the right to (i) use the licensed patent rights for educational and research purposes and research sponsored by commercial entities, (ii) publicly disclose research results, (iii) use the licensed patent rights to offer and perform clinical diagnostic and prognostic care solely within the University of California system, and (iv) allow other non-profit and academic institutions to use the licensed patent rights for educational and research purposes and research sponsored by commercial entities, as well as to publicly disclose research results.

Pursuant to the UCLA Agreement, we paid UCLA an upfront license issue fee of $25,000. We also reimbursed UCLA for its past patent costs, and we have a continuing obligation to reimburse UCLA for its patent costs during the term of the UCLA Agreement. For licensed products that are administered directly to a patient for therapeutic purposes, we are required to pay UCLA up to an aggregate of (i) $825,000 upon the achievement of certain pre-specified development milestones for each of the first three such licensed products, and (ii) $15.0 million upon the achievement of certain pre-specified commercial milestones for such licensed products. In addition, we are obligated to pay an annual license maintenance fee beginning on the first anniversary of the UCLA Agreement until the first commercial sale of a licensed product. The license maintenance fee for the first anniversary was $10,000, and it will subsequently increase by $10,000 per anniversary up to a maximum annual license maintenance fee of $100,000. We are also required to pay, on a country-by-country basis, earned royalty percentages in the low single-digits on net sales of the licensed products, with the royalty rate being subject to reduction upon certain events. Under the UCLA Agreement, we are obligated to pay a minimum annual royalty of $100,000 beginning with the first full calendar year after the first commercial sale of a licensed product, and the minimum annual royalty will be credited against the earned royalty made during the same calendar year. If any claim within the licensed patent rights is held invalid or unenforceable in a final decision by a court of competent jurisdiction, all royalty obligations with respect to that claim or any claim patentably indistinct from it will expire as of the date of that final decision. No royalties will be collected or paid on licensed products sold to the U.S. government to the extent required by law, and we will be required to reduce the amount charged for licensed products distributed to the U.S. government by the amount of the royalty that otherwise would have been paid. Furthermore, we are obligated to pay UCLA tiered fees on a percentage of certain sublicense income in the low single-digit to low double-digit range. Lastly, if we challenge the validity of any licensed patent rights, we agree to pay UCLA all royalties and other amounts due in view of our activities under the UCLA Agreement during the period of challenge. If we fail such challenge, we are required to pay two times the royalty rate paid during the period of such challenge for the remaining term of the UCLA Agreement and all of UCLA’s verifiable legal out-of-pocket fees and costs incurred in defending such challenge, including attorney’s fees.

The UCLA Agreement will terminate on the later of the expiration of the last-to-expire patent or last to be abandoned patent application in the licensed patent rights, which we expect to occur in 2033. We also have the right to terminate the UCLA Agreement in its entirety or with respect to any portion of the licensed patent rights for any reason upon 90 days’ prior written notice to UCLA. UCLA may terminate the UCLA Agreement upon a material breach by us that is not cured within 90 days after receiving written notice. If the breach is incapable of being cured within such period, then UCLA will consider our efforts to avoid, and to take reasonable steps to cure, such breach when determining whether to terminate the UCLA Agreement. Also, UCLA has the right and option, at its sole discretion, to either terminate the UCLA Agreement or reduce our exclusive license to a non-exclusive license if we fail to (i) exercise commercially reasonable and diligent efforts to develop, market, manufacture, and sell licensed products, or

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(ii) achieve certain development milestones set forth in the UCLA Agreement, subject to our ability to extend such milestones in accordance with terms set forth in the UCLA Agreement. Upon our termination of the UCLA Agreement, we may continue to sell any previously manufactured licensed products for 180 days after the effective date of termination. Upon termination of the UCLA Agreement by UCLA for our failure to reimburse UCLA for certain patent costs after the applicable cure period, we may continue to sell all previously made licensed products for 180 days after the effective date of the notice of termination; however, this right is not available if the UCLA Agreement is terminated for any other cause.

Government Regulation

The FDA and other regulatory authorities at federal, state, and local levels, as well as in foreign countries, extensively regulate, among other things, the research, development, testing, manufacture, quality control, import, export, safety, effectiveness, labeling, packaging, storage, distribution, record keeping, approval, advertising, promotion, marketing, post-approval monitoring, and post-approval reporting of biologics such as those we are developing. We, along with third-party contractors, will be required to navigate the various preclinical, clinical and commercial approval requirements of the governing regulatory agencies of the countries in which we wish to conduct studies or seek approval or licensure of our product candidates. The process of obtaining regulatory approvals and the subsequent compliance with applicable federal, state, local and foreign statutes and regulations require the expenditure of substantial time and financial resources.

U.S. Biologics Regulation

In the United States, biological products are subject to regulation under the Federal Food, Drug, and Cosmetic Act, the Public Health Service Act, and other federal, state, local and foreign statutes and regulations. The process required by the FDA before biologics may be marketed in the United States generally involves the following:

Prior to beginning the first clinical trial with a product candidate in the United States, we must submit an IND to the FDA. An IND is a request for authorization from the FDA to administer an investigational new drug to humans. The central focus of an IND submission is on the general investigational plan and the protocol(s) for clinical studies. The IND also includes results of animal and in vitro studies assessing the toxicology, pharmacokinetics, pharmacology, and pharmacodynamic characteristics of the product; chemistry, manufacturing, and controls information; and any available human data or literature to support the use of the investigational product. An IND must become effective before human clinical trials may begin. The IND automatically becomes effective 30 days after receipt by the FDA, unless the FDA, within the 30-day time period, raises safety concerns or questions about the proposed clinical trial. In such a case, the IND may be placed on clinical hold and the IND sponsor and the FDA must resolve any outstanding concerns or questions before the clinical trial can begin. Submission of an IND therefore may or may not result in FDA authorization to begin a clinical trial.

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In addition to the IND submission process, under the National Institutes of Health (NIH), Guidelines for Research Involving Recombinant DNA Molecules, or the NIH Guidelines, supervision of human gene transfer trials includes evaluation and assessment by an institutional biosafety committee (IBC), a local institutional committee that reviews and oversees research utilizing recombinant or synthetic nucleic acid molecules at that institution. The IBC assesses the safety of the research and identifies any potential risk to public health or the environment, and such review may result in some delay before initiation of a clinical trial. While the NIH Guidelines are not mandatory unless the research in question is being conducted at or sponsored by institutions receiving NIH funding of recombinant or synthetic nucleic acid molecule research, many companies and other institutions not otherwise subject to the NIH Guidelines voluntarily follow them.

Clinical trials involve the administration of the investigational product to human subjects under the supervision of qualified investigators in accordance with GCPs, which include the requirement that all research subjects provide their informed consent for their participation in any clinical study. Clinical trials are conducted under protocols detailing, among other things, the objectives of the study, the parameters to be used in monitoring safety and the effectiveness criteria to be evaluated. A separate submission to the existing IND must be made for each successive clinical trial conducted during product development and for any subsequent protocol amendments. Furthermore, an independent IRB for each site proposing to conduct the clinical trial must review and approve the plan for any clinical trial and its informed consent form before the clinical trial begins at that site, and must monitor the study until completed. Regulatory authorities, the IRB or the sponsor may suspend a clinical trial at any time on various grounds, including a finding that the subjects are being exposed to an unacceptable health risk or that the trial is unlikely to meet its stated objectives. Some studies also include oversight by an independent group of qualified experts organized by the clinical study sponsor, known as a data safety monitoring board, which provides authorization for whether or not a study may move forward at designated check points based on access to certain data from the study and may halt the clinical trial if it determines that there is an unacceptable safety risk for subjects or other grounds, such as no demonstration of efficacy. There are also requirements governing the reporting of ongoing clinical studies and clinical study results to public registries.

For purposes of BLA approval, human clinical trials are typically conducted in three sequential phases that may overlap or be combined:

In some cases, the FDA may require, or companies may voluntarily pursue, additional clinical trials after a product is approved to gain more information about the product. These so-called Phase 4 studies may also be made a condition to approval of the BLA. Concurrent with clinical trials, companies may complete additional animal studies and develop additional information about the biological characteristics of the product candidate, and must finalize a process for manufacturing the product in commercial quantities in accordance with cGMP requirements. The manufacturing process must be capable of consistently producing quality batches of the product candidate and, among other things, must develop methods for testing the identity, strength, quality and purity of the final product. Additionally, appropriate packaging must be selected and tested, and stability studies must be conducted to demonstrate that the product candidate does not undergo unacceptable deterioration over its shelf life.

BLA Submission and Review by the FDA

Assuming successful completion of all required testing in accordance with all applicable regulatory requirements, the results of product development, nonclinical studies and clinical trials are submitted to the FDA as part of a BLA requesting approval to market the product for one or more indications. The BLA must include all relevant data available from preclinical and clinical studies, including negative or ambiguous results as well as positive findings, together with detailed information relating to the product’s chemistry, manufacturing, controls, and proposed labeling, among other things. Data can come from company-sponsored clinical studies intended to test the safety and effectiveness of a use of the product, or from a number of alternative sources, including studies initiated by independent investigators. The submission of a BLA requires payment of a substantial application user fee to the FDA, unless a waiver or exemption applies.

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Within 60 days following submission of the application, the FDA reviews a BLA submitted to determine if it is substantially complete before the FDA accepts it for filing. The FDA may refuse to file any BLA that it deems incomplete or not properly reviewable at the time of submission and may request additional information. In this event, the BLA must be resubmitted with the additional information. Once a BLA has been accepted for filing, the FDA’s goal is to review standard applications within ten months after the filing date, or, if the application qualifies for priority review, six months after the FDA accepts the application for filing. In both standard and priority reviews, the review process may also be extended by FDA requests for additional information or clarification. The FDA reviews a BLA to determine, among other things, whether a product is safe, pure and potent and the facility in which it is manufactured, processed, packed or held meets standards designed to assure the product’s continued safety, purity and potency. The FDA may also convene an advisory committee to provide clinical insight on application review questions. The FDA is not bound by the recommendations of an advisory committee, but it considers such recommendations carefully when making decisions.

Before approving a BLA, the FDA will typically inspect the facility or facilities where the product is manufactured. The FDA will not approve an application unless it determines that the manufacturing processes and facilities are in compliance with cGMP and adequate to assure consistent production of the product within required specifications. For a product candidate that is also a human cellular or tissue product, the FDA also will not approve the application if the manufacturer is not in compliance with cGTPs. These are FDA regulations that govern the methods used in, and the facilities and controls used for, the manufacture of human cells, tissues, and cellular and tissue based products (HCT/Ps) which are human cells or tissue intended for implantation, transplant, infusion, or transfer into a human recipient. The primary intent of the GTP requirements is to ensure that cell and tissue based products are manufactured in a manner designed to prevent the introduction, transmission and spread of communicable disease. FDA regulations also require tissue establishments to register and list their HCT/Ps with the FDA and, when applicable, to evaluate donors through screening and testing. Additionally, before approving a BLA, the FDA will typically inspect one or more clinical sites to assure compliance with GCP. If the FDA determines that the application, manufacturing process or manufacturing facilities are not acceptable, it will outline the deficiencies in the submission and often will request additional testing or information. Notwithstanding the submission of any requested additional information, the FDA ultimately may decide that the application does not satisfy the regulatory criteria for approval.

After the FDA evaluates a BLA and conducts inspections of manufacturing facilities where the investigational product and/or its drug substance will be produced, the FDA may issue an approval letter or a Complete Response Letter (CRL). An approval letter authorizes commercial marketing of the product with specific prescribing information for specific indications. A CRL will describe all of the deficiencies that the FDA has identified in the BLA, except that where the FDA determines that the data supporting the application are inadequate to support approval, the FDA may issue the CRL without first conducting required inspections, testing submitted product lots, and/or reviewing proposed labeling. In issuing the CRL, the FDA may recommend actions that the applicant might take to place the BLA in condition for approval, including requests for additional information or clarification. The FDA may delay or refuse approval of a BLA if applicable regulatory criteria are not satisfied, require additional testing or information and/or require post-marketing testing and surveillance to monitor safety or efficacy of a product.

If regulatory approval of a product is granted, such approval will be granted for particular indications and may entail limitations on the indicated uses for which such product may be marketed. For example, the FDA may approve the BLA with a Risk Evaluation and Mitigation Strategy (REMS), to ensure the benefits of the product outweigh its risks. A REMS is a safety strategy implemented to manage a known or potential serious risk associated with a product and to enable patients to have continued access to such medicines by managing their safe use, and could include medication guides, physician communication plans, or elements to assure safe use, such as restricted distribution methods, patient registries and other risk minimization tools. The FDA also may condition approval on, among other things, changes to proposed labeling or the development of adequate controls and specifications. Once approved, the FDA may withdraw the product approval if compliance with pre- and post-marketing requirements is not maintained or if problems occur after the product reaches the marketplace. The FDA may require one or more Phase 4 post-market studies and surveillance to further assess and monitor the product’s safety and effectiveness after commercialization, and may limit further marketing of the product based on the results of these post-marketing studies.

Expedited development and review programs

The FDA offers a number of expedited development and review programs for qualifying product candidates. For example, the fast track program is intended to expedite or facilitate the process for reviewing new products that are intended to treat a serious or life-threatening disease or condition and demonstrate the potential to address unmet medical needs for the disease or condition. Fast track designation applies to the combination of the product and the specific indication for which it is being studied. The sponsor of a fast track product has opportunities for more frequent interactions with the applicable FDA review team during product development and, once a BLA is submitted, the product candidate may be eligible for priority review. A fast track product may also be eligible for rolling review, where the FDA may consider for review sections of the BLA on a rolling basis before the complete application is submitted, if the sponsor provides a schedule for the submission of the sections of the BLA, the FDA agrees to accept sections of the

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BLA and determines that the schedule is acceptable, and the sponsor pays any required user fees upon submission of the first section of the BLA.

A product candidate intended to treat a serious or life-threatening disease or condition may also be eligible for breakthrough therapy designation to expedite its development and review. A product candidate can receive breakthrough therapy designation if preliminary clinical evidence indicates that the product candidate, alone or in combination with one or more other drugs or biologics, may demonstrate substantial improvement over existing therapies on one or more clinically significant endpoints, such as substantial treatment effects observed early in clinical development. The designation includes all of the fast track program features, as well as more intensive FDA interaction and guidance beginning as early as Phase 1 and an organizational commitment to expedite the development and review of the product candidate, including involvement of senior managers.

Any marketing application for a drug or biologic submitted to the FDA for approval, including a product candidate with a fast track designation and/or breakthrough therapy designation, may be eligible for other types of FDA programs intended to expedite the FDA review and approval process, such as priority review and accelerated approval. A product candidate is eligible for priority review if it is designed to treat a serious or life-threatening disease or condition, and if approved, would provide a significant improvement in safety or effectiveness compared to available alternatives for such disease or condition. For original BLAs, priority review designation means the FDA’s goal is to take action on the marketing application within six months of the 60-day filing date (as compared to ten months under standard review).

Additionally, product candidates studied for their safety and effectiveness in treating serious or life-threatening diseases or conditions may receive accelerated approval upon a determination that the product has an effect on a surrogate endpoint that is reasonably likely to predict clinical benefit, or on a clinical endpoint that can be measured earlier than irreversible morbidity or mortality, that is reasonably likely to predict an effect on irreversible morbidity or mortality or other clinical benefit, taking into account the severity, rarity, or prevalence of the condition and the availability or lack of alternative treatments. As a condition of accelerated approval, the FDA will generally require the sponsor to perform adequate and well-controlled post-marketing clinical studies to verify and describe the anticipated effect on irreversible morbidity or mortality or other clinical benefit. Products receiving accelerated approval may be subject to expedited withdrawal procedures if the sponsor fails to conduct the required post-marketing studies or if such studies fail to verify the predicted clinical benefit. In addition, the FDA currently requires as a condition for accelerated approval pre-approval of promotional materials, which could adversely impact the timing of the commercial launch of the product.

In 2017, the FDA established a new regenerative medicine advanced therapy (RMAT), designation as part of its implementation of the 21st Century Cures Act. The RMAT designation program is intended to fulfill the 21st Century Cures Act requirement that the FDA facilitate an efficient development program for, and expedite review of, any drug or biologic that meets the following criteria: (i) the drug or biologic qualifies as a RMAT, which is defined as a cell therapy, therapeutic tissue engineering product, human cell and tissue product, or any combination product using such therapies or products, with limited exceptions; (ii) the drug or biologic is intended to treat, modify, reverse, or cure a serious or life-threatening disease or condition; and (iii) preliminary clinical evidence indicates that the drug or biologic has the potential to address unmet medical needs for such a disease or condition. RMAT designation provides all the benefits of breakthrough therapy designation, including more frequent meetings with the FDA to discuss the development plan for the product candidate and eligibility for rolling review and priority review. Product candidates granted RMAT designation may also be eligible for accelerated approval on the basis of a surrogate or intermediate endpoint reasonably likely to predict long-term clinical benefit, or reliance upon data obtained from a meaningful number of clinical trial sites, including through expansion of trials to additional sites.

Fast track designation, breakthrough therapy designation, priority review, accelerated approval, and RMAT designation do not change the standards for approval but may expedite the development or approval process. Even if a product candidate qualifies for one or more of these programs, the FDA may later decide that the product no longer meets the conditions for qualification or decide that the time period for FDA review or approval will not be shortened.

Orphan drug designation and exclusivity

Under the Orphan Drug Act, the FDA may grant orphan designation to a drug or biologic intended to treat a rare disease or condition, defined as a disease or condition with a patient population of fewer than 200,000 individuals in the United States, or a patient population greater than 200,000 individuals in the United States and when there is no reasonable expectation that the cost of developing and making available the drug or biologic in the United States will be recovered from sales in the United States for that drug or biologic. Orphan drug designation must be requested before submitting a BLA. After the FDA grants orphan drug designation, the generic identity of the therapeutic agent and its potential orphan use are disclosed publicly by the FDA.

If a product that has orphan drug designation subsequently receives the first FDA approval for a particular active ingredient for the disease for which it has such designation, the product is entitled to orphan product exclusivity, which means that the FDA may not

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approve any other applications, including a full BLA, to market the same biologic for the same indication for seven years, except in limited circumstances, such as a showing of clinical superiority to the product with orphan drug exclusivity or if the FDA finds that the holder of the orphan drug exclusivity has not shown that it can assure the availability of sufficient quantities of the orphan drug to meet the needs of patients with the disease or condition for which the drug was designated. Orphan drug exclusivity does not prevent the FDA from approving a different drug or biologic for the same disease or condition, or the same drug or biologic for a different disease or condition. Among the other benefits of orphan drug designation are tax credits for certain research and a waiver of the BLA application user fee.

A designated orphan drug may not receive orphan drug exclusivity if it is approved for a use that is broader than the indication for which it received orphan designation. In addition, orphan drug exclusive marketing rights in the United States may be lost if the FDA later determines that the request for designation was materially defective or, as noted above, if a second applicant demonstrates that its product is clinically superior to the approved product with orphan exclusivity or the manufacturer of the approved product is unable to assure sufficient quantities of the product to meet the needs of patients with the rare disease or condition.

Post-approval requirements

Biologics are subject to pervasive and continuing regulation by the FDA, including, among other things, requirements relating to record-keeping, reporting of adverse experiences, periodic reporting, product sampling and distribution, and advertising and promotion of the product. After approval, most changes to the approved product, such as adding new indications or other labeling claims, are subject to prior FDA review and approval. There also are continuing, annual program fees for any marketed products. Biologic manufacturers and their subcontractors are required to register their establishments with the FDA and certain state agencies, and are subject to periodic unannounced inspections by the FDA and certain state agencies for compliance with cGMP, which impose certain procedural and documentation requirements up. Changes to the manufacturing process are strictly regulated, and, depending on the significance of the change, may require prior FDA approval before being implemented. FDA regulations also require investigation and correction of any deviations from cGMP and impose reporting requirements. Accordingly, manufacturers must continue to expend time, money and effort in the area of production and quality control to maintain compliance with cGMP and other aspects of regulatory compliance.

The FDA may withdraw approval if compliance with regulatory requirements and standards is not maintained or if problems occur after the product reaches the market. Later discovery of previously unknown problems with a product, including adverse events of unanticipated severity or frequency, or with manufacturing processes, or failure to comply with regulatory requirements, may result in revisions to the approved labeling to add new safety information; imposition of post-market studies or clinical studies to assess new safety risks; or imposition of distribution restrictions or other restrictions under a REMS program. Other potential consequences include, among other things:

The FDA closely regulates the marketing, labeling, advertising and promotion of biologics. A company can make only those claims relating to safety and efficacy, purity and potency that are approved by the FDA and in accordance with the provisions of the approved label. The FDA and other agencies actively enforce the laws and regulations prohibiting the promotion of off-label uses. Failure to comply with these requirements can result in, among other things, adverse publicity, warning letters, corrective advertising and potential civil and criminal penalties. Physicians may prescribe legally available products for uses that are not described in the product’s labeling and that differ from those tested and approved by the FDA. Such off-label uses are common across medical specialties. Physicians may believe that such off-label uses are the best treatment for many patients in varied circumstances. The FDA

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does not regulate the behavior of physicians in their choice of treatments. The FDA does, however, restrict manufacturer’s communications on the subject of off-label use of their products.

Biosimilars and reference product exclusivity

The Affordable Care Act, signed into law in 2010, includes a subtitle called the Biologics Price Competition and Innovation Act (BPCIA), which created an abbreviated approval pathway for biological products that are biosimilar to or interchangeable with an FDA-licensed reference biological product. The FDA has issued several guidance documents outlining an approach to review and approval of biosimilars.

Biosimilarity, which requires that there be no clinically meaningful differences between the biological product and the reference product in terms of safety, purity, and potency, can be shown through analytical studies, animal studies, and a clinical study or studies. Interchangeability requires that a product is biosimilar to the reference product and the product must demonstrate that it can be expected to produce the same clinical results as the reference product in any given patient and, for products that are administered multiple times to an individual, the biologic and the reference biologic may be alternated or switched after one has been previously administered without increasing safety risks or risks of diminished efficacy relative to exclusive use of the reference biologic. However, complexities associated with the larger, and often more complex, structures of biological products, as well as the processes by which such products are manufactured, pose significant hurdles to implementation of the abbreviated approval pathway that are still being worked out by the FDA.

Under the BPCIA, an application for a biosimilar product may not be submitted to the FDA until four years following the date that the reference product was first licensed by the FDA. In addition, the approval of a biosimilar product may not be made effective by the FDA until 12 years from the date on which the reference product was first licensed. During this 12-year period of exclusivity, another company may still market a competing version of the reference product if the FDA approves a full BLA for the competing product containing that applicant’s own preclinical data and data from adequate and well-controlled clinical trials to demonstrate the safety, purity and potency of its product. The BPCIA also created certain exclusivity periods for biosimilars approved as interchangeable products. At this juncture, it is unclear whether products deemed “interchangeable” by the FDA will, in fact, be readily substituted by pharmacies, which are governed by state pharmacy law.

A biological product can also obtain pediatric market exclusivity in the United States. Pediatric exclusivity, if granted, adds six months to existing exclusivity periods and patent terms. This six-month exclusivity, which runs from the end of other exclusivity protection or patent term, may be granted based on the voluntary completion of a pediatric study in accordance with an FDA-issued “Written Request” for such a study. The BPCIA is complex and continues to be interpreted and implemented by the FDA. In addition, government proposals have sought to reduce the 12-year reference product exclusivity period. Other aspects of the BPCIA, some of which may impact the BPCIA exclusivity provisions, have also been the subject of recent litigation. As a result, the ultimate impact, implementation, and impact of the BPCIA is subject to significant uncertainty.

Other Healthcare Laws

Pharmaceutical companies are subject to additional healthcare regulation and enforcement by the federal government and by authorities in the states and foreign jurisdictions in which they conduct their business and may constrain the financial arrangements and relationships through which we research, as well as, sell, market and distribute any products for which we obtain marketing approval. Such laws include, without limitation, federal and state anti-kickback, fraud and abuse, false claims, data privacy and security and physician and other health care provider transparency laws and regulations. If our significant operations are found to be in violation of any of such laws or any other governmental regulations that apply, they may be subject to penalties, including, without limitation, administrative, civil and criminal penalties, damages, fines, disgorgement, the curtailment or restructuring of operations, integrity oversight and reporting obligations, exclusion from participation in federal and state healthcare programs and imprisonment.

Coverage and Reimbursement

Sales of any product depend, in part, on the extent to which such product will be covered by third-party payors, such as federal, state, and foreign government healthcare programs, commercial insurance and managed healthcare organizations, and the level of reimbursement for such product by third-party payors. Decisions regarding the extent of coverage and amount of reimbursement to be provided are made on a plan-by-plan basis. These third-party payors are increasingly reducing reimbursements for medical products, drugs and services. In addition, the U.S. government, state legislatures and foreign governments have continued implementing cost-containment programs, including price controls, restrictions on coverage and reimbursement and requirements for substitution of generic products. Adoption of price controls and cost-containment measures, and adoption of more restrictive policies in jurisdictions with existing controls and measures, could further limit sales of any product. Decreases in third-party reimbursement for any product or a decision by a third-party payor not to cover a product could reduce physician usage and patient demand for the product and also have a material adverse effect on sales.

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Healthcare Reform

In March 2010, the Patient Protection and Affordable Care Act, as amended by the Health Care and Education Reconciliation Act, each as amended, collectively known as the ACA, was enacted, which substantially changed the way healthcare is financed by both governmental and private insurers, and significantly affected the pharmaceutical industry. The ACA contains a number of provisions, including those governing enrollment in federal healthcare programs, reimbursement adjustments and changes to fraud and abuse laws. For example, the ACA:

Since its enactment, there have been judicial and Congressional challenges to certain aspects of the ACA, and we expect there will be additional challenges and amendments to the ACA in the future. For example, on March 2, 2020 the United States Supreme Court granted the petitions for writs of certiorari to review the U.S. Court of Appeals for the 5th Circuit ruling that the individual mandate was unconstitutional and to determine the constitutionality of the ACA in its entirety. It is uncertain when the Supreme Court will rule on this case. Other legislative changes have been proposed and adopted since the ACA was enacted, including aggregate reductions of Medicare payments to providers of 2% per fiscal year, which was temporarily suspended from May 1, 2020 through March 31, 2021 due to the COVID-19 pandemic, and reduced payments to several types of Medicare providers. Moreover, there has recently been heightened governmental scrutiny over the manner in which manufacturers set prices for their marketed products, which has resulted in several Congressional inquiries, proposed and enacted legislation and executive orders issued by the President designed to, among other things, bring more transparency to product pricing, review the relationship between pricing and manufacturer patient programs, and reform government program reimbursement methodologies for drug products. It is also possible that additional governmental action is taken in response to the COVID-19 pandemic. Individual states in the United States have also become increasingly active in implementing regulations designed to control pharmaceutical product pricing, including price or patient reimbursement constraints, discounts, restrictions on certain product access and marketing cost disclosure and transparency measures, and, in some cases, designed to encourage importation from other countries and bulk purchasing.

Employees and Human Capital Resources

As of December 31, 2021, we had 383 employees, 302 of whom were primarily engaged in research and development activities. A total of 236 employees have an advanced degree. None of our employees are represented by a labor union or party to a collective bargaining agreement. We consider our relationship with our employees to be good.

Our human capital resources objectives include, as applicable, identifying, recruiting, retaining, incentivizing and integrating our existing and additional employees. The principal purposes of our equity incentive plans are to attract, retain and motivate selected employees, consultants and directors through the granting of stock-based compensation awards and cash-based performance bonus awards.

Legal Proceedings

We are not currently a party to any material legal proceedings. From time to time, we may, however, in the ordinary course of business face various claims brought by third parties, and we may, from time to time, make claims or take legal actions to assert our rights, including intellectual property rights as well as claims relating to employment matters and the safety or efficacy of our products. Any of these claims could subject us to costly litigation, and, while we generally believe that we have adequate insurance to cover many different types of liabilities, our insurance carriers may deny coverage, may be inadequately capitalized to pay on valid claims, or our policy limits may be inadequate to fully satisfy any damage awards or settlements. If this were to happen, the payment of any such awards could have a material adverse effect on our operations, cash flows and financial position. Additionally, any such claims, whether or not successful, could damage our reputation and business.

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Our Corporate Information

We were founded in July 2018 as a Delaware corporation. Our principal executive offices are located at 188 East Blaine Street, Suite 400, Seattle, Washington 98102, and our telephone number is (206) 701-7914. Our website address is www.sana.com. The information on, or that can be accessed through, our website is not part of this report, and is not incorporated by reference herein. We have included our website address as an inactive textual reference only. We may use our website as a means of disclosing material non-public information and for complying with our disclosure obligations under Regulation Fair Disclosure promulgated by the SEC. These disclosures will be included on our website under the “Investors” section.

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Item 1A. Risk Factors.

Investing in shares of our common stock involves a high degree of risk. You should carefully consider the following risks and uncertainties, together with all of the other information contained in this Annual Report, including our financial statements and related notes included elsewhere in this Annual Report, before making an investment decision. The risks described below are not the only ones facing us. Moreover, we may have already experienced the circumstances described in one or more of the risk factors described below. Many of the following risks and uncertainties are, and will continue to be, exacerbated by the ongoing COVID-19 pandemic and any worsening of the global business and economic environment as a result. The occurrence of any of the following risks, or of additional risks and uncertainties not presently known to us or that we currently believe to be immaterial, could materially and adversely affect our business, financial condition, reputation, or results of operations. In such a case, the trading price of shares of our common stock could decline, and you may lose all or part of your investment.

Risks Related to Our Business and Industry

Our ex vivo and in vivo cell engineering platforms are based on novel technologies that are unproven and may not result in approvable or marketable products. This uncertainty exposes us to unforeseen risks, makes it difficult for us to predict the time and cost that will be required for the development and potential regulatory approval of our product candidates and increases the risk that we may ultimately not be successful in our efforts to use and expand our technology platforms to build a pipeline of product candidates.

We are seeking to identify and develop a broad pipeline of product candidates using our ex vivo and in vivo cell engineering platforms. We have not commenced clinical trials for any product candidates developed with these platforms. The scientific research that forms the basis of our efforts to develop product candidates with our platforms is still ongoing. We are not aware of any United Stated Food and Drug Administration (FDA)-approved therapeutics that utilize fusogen technology or that are cell products derived from pluripotent stem cells (PSCs). Further, the scientific evidence that supports the feasibility of developing therapeutic treatments based on our platforms is both preliminary and limited. As a result, we are exposed to a number of unforeseen risks, and it is difficult to predict the types of challenges and risks that we may encounter during development of our product candidates. For example, we have not tested our cell engineering platforms on all pluripotent and differentiated cell types or in all microenvironments, so results from one cell type or microenvironment may not translate into other cell types or microenvironments. In addition, our current gene editing approaches rely on novel gene editing reagents that may have unanticipated or undesirable effects or prove to be less effective than we expect. Also, we have not tested any of the product candidates that we are developing using our cell engineering platforms in humans, and our current data is limited to animal models and preclinical cell lines, the results of which may not translate into humans. Further, relevant animal models and assays may not accurately predict the safety and efficacy of our product candidates in humans, and we may encounter significant challenges creating appropriate models and assays for demonstrating the safety and purity of our product candidates.

In addition, our fusogen and hypoimmune technologies have potential safety risks, including those related to genotoxicity associated with the delivery of genome-modifying payloads. For example, DNA sequences that randomly integrate into a cell’s DNA may increase risk for or cause certain cancers. Alternatively, gene-editing approaches may edit the genome at sites other than the intended DNA target or cause DNA rearrangements, each of which may have oncogenic or other adverse effects. PSC-derived cell products may have potential safety risks related to genomic variations that have been observed during passage (i.e., amplification) and differentiation of pluripotent cell lines. We cannot always predict the types and potential impact of these genomic changes, including whether certain changes are harmful. Accordingly, it may be difficult for us to conduct the level of testing and development of assays necessary to ensure the safety of our PSC-derived cell product candidates in humans. These risks related to genetic variation are also relevant to our product candidates created from donor-derived cells. Additionally, our stem cell-based product candidates have potential safety risks related to insufficient cell differentiation that may lead to oncogenic transformations or other adverse effects. As a result, it is possible that safety events or concerns could negatively affect the development of our product candidates, including by adversely affecting patient enrollment in future clinical trials of our product candidates among the patient populations that we intend to treat.

Given the novelty of our technologies, we intend to work closely with the FDA and comparable foreign regulatory authorities to perform the requisite scientific analyses and evaluation of our methods to obtain regulatory approval for our product candidates. However, due to a lack of experience with similar therapeutics, the regulatory pathway with the FDA and comparable regulatory authorities may be more complex, time-consuming, and unpredictable relative to more well-known therapeutics. Even if we obtain human data to support continued evaluation and approval of our product candidates, the FDA or comparable foreign regulatory authorities may lack experience in evaluating the safety and efficacy of therapeutics similar to our product candidates. For example, given that there are no approved PSC- or donor-derived cell products on the market, the FDA and comparable foreign regulatory authorities have not established consistent standards by which to evaluate the safety of such products, and any such standards that they do establish may subsequently change. Moreover, the FDA has increased its focus in recent years on potential safety issues associated with gene and cell therapy products, including by placing clinical holds on certain product candidates pending further evaluation of genomic abnormalities detected in as few as a single patient following administration of such product candidates. We cannot be

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certain that the FDA or comparable foreign regulatory authorities will determine that the potential safety risks associated with our PSC- or donor-derived cell product candidates outweigh the potential therapeutic benefits, and that they will allow us to commence clinical trials of such product candidates in a timely manner, or at all, or to continue such clinical trials once they have commenced. If we become subject to a clinical hold with respect to any of our product candidates due to a potential safety issue, we cannot guarantee that we will be able to provide the applicable regulatory authority with sufficient data or other evidence regarding the safety of such product candidate such that we can resume clinical development of such product candidates in a timely manner or at all. This could delay clinical development of such product candidate or our other product candidates, increase our expected development costs, increase the length of the regulatory review process, and delay or prevent commercialization of our product candidates. Moreover, even if we and the applicable regulatory authorities determine that our product candidates are safe in humans, and such products obtain approval, they may later prove to cause serious adverse side effects in patients that we were unable to observe or predict during the clinical development of such product candidates, which may subject us to significant negative consequences, as described elsewhere in these Risk Factors. In addition, the evaluation process for our product candidates takes time and resources and may require independent third-party analyses, and our product candidates may not be accepted or approved by the FDA or comparable foreign regulatory authorities. We cannot be certain that our ex vivo and in vivo cell engineering platforms will lead to the development of approvable or marketable products, either alone or in combination with other therapies.

Additionally, a key element of our strategy is to use and expand our ex vivo and in vivo cell engineering platforms to build a pipeline of product candidates and advance those product candidates through clinical development for the treatment of a variety of different types of diseases. Although our research and development efforts to date have been focused on identifying a pipeline of product candidates directed at various disease types, we may not be able to develop product candidates that are safe and effective. Even if we are successful in building our pipeline, the potential product candidates that we identify may not be suitable for clinical development, including if they are shown to have harmful side effects or other characteristics that indicate that they are unlikely to receive marketing approval and achieve market acceptance. If we do not successfully develop, obtain approval for, and commercialize any of our current or future product candidates, we will face difficulty in generating product revenue in future periods, which could result in significant harm to our financial position and adversely affect our share price.

If we are unable to successfully identify, develop, and commercialize any product candidates, or experience significant delays in doing so, our business, financial condition, and results of operations will be materially adversely affected.

Our ability to generate revenue from sales of any of our product candidates, which we do not expect to occur for at least the next several years, if ever, will depend heavily on the timely and successful identification, development, regulatory approval, and eventual commercialization of any such product candidates, which may never occur. To date, we have not generated revenue from sales of any products, and we may never be able to develop, obtain regulatory approval for, or commercialize a marketable product. All of our current product candidates are in preclinical development, and, before we generate any revenue from product sales, will require that we manage preclinical, clinical, and manufacturing activities, undertake significant clinical development, obtain regulatory approval in multiple jurisdictions, establish manufacturing supply, including commercial manufacturing supply, and build a commercial organization, which will require a substantial investment and significant marketing efforts. We may never receive regulatory approval for any of our product candidates, which would prevent us from marketing or promoting any of our product candidates.

The successful development of our product candidates will depend on numerous factors, including the following:

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Additionally, clinical or regulatory setbacks experienced by other companies developing similar products or within adjacent fields, including allogeneic cell-based therapies and the fields of gene editing and gene therapy, may impact the clinical development of and regulatory pathway for our current or future product candidates or negatively impact the perceptions of value or risk of our technologies.

If we experience issues with or delays with respect to any one or more of these factors, we could experience significant delays or be unable to successfully develop and commercialize our product candidates, which would materially adversely affect our business, financial condition, and results of operations.

While we believe our pipeline will yield multiple INDs, we may not be able to submit INDs to commence clinical trials on the timelines we expect, and even if we are able to submit an IND, the FDA may not permit us to proceed with clinical trials.

We expect our pipeline to yield multiple Investigational New Drug applications (INDs) beginning as early as 2022, including INDs for our allogeneic CAR T cell product candidates from our ex vivo cell engineering platform and our fusosome CAR T product candidates from our in vivo cell engineering platform. We cannot be sure that, following our submission of an IND, the FDA or comparable foreign regulatory authorities will allow our clinical trials to begin, or that, once begun, issues will not arise that require suspension or termination of such clinical trials. The manufacturing of our product candidates, including our CAR T ex vivo cell engineering product candidates, remains an emerging and evolving field. Accordingly, we expect topics relating to chemistry, manufacturing, and controls, including product specifications, will be a focus of IND reviews, which may delay the clearance of INDs that we submit. Additionally, even if applicable regulatory authorities agree with the design and implementation of the clinical trials set forth in an IND or comparable foreign submission, such regulatory authorities may change their requirements in the future, which could require us to make costly changes to and delay the conduct of our clinical trials or require suspension or termination of such trials entirely.

We may not realize the benefits of technologies that we have acquired, or will acquire in the future, or other strategic transactions that we have or will consummate.

Our ex vivo and in vivo cell engineering technology represents an aggregation of years of innovation and technology from multiple academic institutions and companies, including our fusogen technology that we acquired from Cobalt, our ex vivo cell engineering programs focused on replacing damaged cells in the heart and certain brain disorders that we acquired from Cytocardia Inc. (Cytocardia) and Oscine Corp. (Oscine), respectively, hypoimmune technology that we licensed from Harvard and The Regents of the University of California (UCSF), and gene editing technology that we licensed from Beam Therapeutics Inc., among others. Further, a key component of our strategy is to acquire and in-license technologies to support our mission of using engineered cells as medicines. As such, we actively evaluate various strategic transactions on an ongoing basis. We may acquire other businesses, products, or technologies, as well as pursue joint ventures or investments in complementary businesses. The level of success of these strategic transactions, including any future strategic transactions, will depend on the risks and uncertainties involved, including:

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In addition, foreign acquisitions and joint ventures are subject to additional risks, including those related to integration of operations across different cultures and languages, currency risks, potentially adverse tax consequences of overseas operations, and the particular economic, political, and regulatory risks associated with specific countries. The occurrence of any of these risks or uncertainties may preclude us from realizing the anticipated benefit of any acquisition or strategic transaction, and our financial condition may be harmed.

Additionally, we may not be successful in our efforts to acquire or obtain rights to certain technologies or products that are necessary for the success of our product candidates on acceptable terms or at all, including because we may be unable to successfully or timely negotiate the terms of an agreement with the third-party owner of such technology or products or because such third party may have determined to deprioritize such technology or products. If we are not able to acquire or obtain rights to certain technologies or products on which certain of our product candidates may depend, it may be necessary for us to curtail, reduce, or delay the development of such product candidates.

We may not realize the benefits of any collaborative or licensing arrangement, and if we fail to enter into new strategic relationships, our business, financial condition, commercialization prospects, and results of operations may be materially adversely affected.

Our product development programs and the potential commercialization of our product candidates will require substantial additional cash to fund expenses. In addition, our ex vivo and in vivo cell engineering platforms are attractive technologies for potential collaborations due to their breadth of application. Therefore, for certain of our product candidates, including product candidates that we may develop in the future, we may decide to form or seek strategic alliances, collaborations, or licensing arrangements with pharmaceutical or biotechnology companies that we believe will complement or augment our development and potential commercialization efforts with respect to such product candidates, including in territories outside the United States or for certain indications.

We face significant competition in seeking appropriate collaborators. Collaborations are complex and time-consuming to negotiate and document. We may not be successful in our efforts to establish a strategic partnership or other alternative arrangements for our product candidates on acceptable terms or at all, including because our product candidates may be deemed to be at too early of a stage of development for collaborative effort or third parties may not view our product candidates as having the requisite potential to demonstrate safety and efficacy. Additionally, there have been a significant number of recent business combinations among large pharmaceutical companies that have reduced the number of potential future collaborators and changed the strategies of the resulting combined companies. In addition, under the terms of certain license agreements applicable to our product candidates, we may be restricted from entering into agreements on certain terms or at all with potential collaborators relating to those product candidates. If and when we collaborate with a third party for development and commercialization of a product candidate, we expect that we may have to relinquish some or all of the control over the future success of that product candidate to the third party. Our ability to reach a definitive agreement for a collaboration will depend, among other things, upon our assessment of the collaborator’s resources and expertise, the terms and conditions of the proposed collaboration, and the proposed collaborator’s evaluation of our technologies, product candidates, and market opportunities. The collaborator may also consider alternative product candidates or technologies for similar indications that may be available for collaboration and could determine that such other collaboration is more attractive than a collaboration with us for our product candidate.

In instances where we do enter into collaborations, we could be subject to the following risks, each of which may materially harm our business, commercialization prospects, and financial condition:

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If our strategic collaborations do not result in the successful development and commercialization of product candidates, or if one of our collaborators terminates its agreement with us, we may not receive any future research funding or milestone or royalty payments under the collaboration or the research, development, and commercialization product that is the subject of the collaboration may be delayed. Moreover, our estimates of the potential revenue we are eligible to receive under our strategic collaborations may include potential payments related to therapeutic programs for which our collaborators have discontinued development or may discontinue development in the future. If we are unable to enter into strategic collaborations, or if any of the other events described in this paragraph occur after we enter into a collaboration, we may have to curtail the development of a particular product candidate, reduce or delay its development program or one or more of our other development programs, delay its potential commercialization or reduce the scope of our sales or marketing activities, or increase our expenditures and undertake development or commercialization activities at our own expense. If we elect to increase our expenditures to fund development or commercialization activities on our own, we may need to obtain additional capital, which may not be available to us on acceptable terms or at all. If we do not have sufficient funds, we will not be able to bring our product candidates to market and generate product revenue.

If we license products or businesses, we may not be able to realize the benefit of such transactions if we are unable to successfully integrate them with our existing operations and company culture. In addition, the success of our collaborations or other transactions may be negatively affected, including as a result of delays in timelines, if the ongoing COVID-19 pandemic materially adversely impacts our or the counterparty’s operations. We also cannot be certain that, following execution of a strategic transaction, we will achieve the revenue or specific net income that justifies such a transaction or the other anticipated benefits that led us to enter into the arrangement.

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Our ability to develop our cell engineering platforms and product candidates and our future growth depends on retaining our key personnel and recruiting additional qualified personnel.

Our success depends upon the continued contributions of our key management, scientific, and technical personnel, many of whom have been instrumental for us and have substantial experience with our cell engineering platforms, underlying technologies, and related product candidates. Given the specialized nature of our ex vivo and in vivo cell engineering and the fact that we are operating in novel and emerging fields, there is an inherent scarcity of personnel with the requisite experience to fill the roles across our organization. As we continue developing our product candidates and building our pipeline, we will require personnel with medical, scientific, or technical qualifications specific to each program. The loss of key managers and senior scientists could delay our research and development activities. Despite our efforts to retain valuable employees, members of our management, scientific, and development teams may terminate their employment with us at any time, sometimes on short notice. Although we have employment agreements with certain of our key employees, our employment relationship with all employees provides for at-will employment, which means that any of our employees could leave our employment at any time, with or without notice. If our retention efforts are unsuccessful now or in the future, it may be difficult for us to implement our business strategy, which could have a material adverse effect on our business.

Further, certain of our key employees, including Drs. Terry Fry, Steve Goldman and Chuck Murry, retain partial employment at academic institutions. Dr. Goldman currently devotes approximately 60% of his time to the University of Rochester and the University of Copenhagen, Dr. Murry currently devotes approximately 25% to his time to the University of Washington, and Dr. Fry currently devotes approximately 25% of his time to the University of Colorado. We may in the future have other employees that have similar employment arrangements. These arrangements may expose us to increased potential for these individuals to return to their academic positions full-time or devote less of their attention to us than is optimal, and potentially expose us to claims of intellectual property ownership or co-ownership by the respective academic institutions.

The competition for qualified personnel in the biotechnology and pharmaceutical industries is intense, and our future success depends upon our ability to attract, retain, and motivate highly skilled scientific, technical, and managerial employees. Specifically, the success of our research and development programs, clinical operations, manufacturing, and future sales and marketing efforts will depend on our ability to attract and retain highly-skilled scientists, engineers, clinical operations and manufacturing personnel, and sales professionals. We face competition for personnel from other companies, universities, public and private research institutions, and other organizations. We have from time to time experienced, and we expect to continue to experience, difficulty in hiring and retaining employees with appropriate qualifications on acceptable terms, or at all. Many of the companies with which we compete for experienced personnel have greater resources than we do and may be able to provide prospective job candidates or our existing employees with more attractive roles, salaries, or benefits than we can provide. If we hire employees from competitors or other companies, their former employers may attempt to assert that these employees or we have breached legal obligations, resulting in a diversion of our time and resources and, potentially, damages. In addition, job candidates and existing employees often consider the value of the stock awards they receive in connection with their employment. If the perceived benefits of our stock awards decline or are otherwise viewed unfavorably compared to those of companies with which we compete for talent, our ability to recruit and retain highly skilled employees could be harmed. If we fail to attract new personnel or fail to retain and motivate our current personnel, our business and future growth prospects would be harmed.

Though many of our personnel have significant experience with respect to manufacturing biopharmaceutical products, we, as a company, do not have experience in developing or maintaining a manufacturing facility. We cannot guarantee that we will be able to maintain a compliant facility and manufacture our product candidates as intended, given the complexity of manufacturing novel therapeutics. If we fail to successfully operate our facility and manufacture a sufficient and compliant supply of our product candidates, our clinical trials and the commercial viability of our product candidates could be adversely affected.

The manufacture of biopharmaceutical products is complex and requires significant expertise, including the development of advanced manufacturing techniques and process controls. Manufacturers of gene and cell therapy products often encounter difficulties in production, particularly in scaling up, scaling out, validating initial production, ensuring the absence of contamination, and ensuring process robustness after initial production. These include difficulties with production costs and yields, quality control, including stability of the product, quality assurance testing, operator error, and shortages of qualified personnel, as well as compliance with strictly enforced federal, state, and foreign regulations. As a result of the complexities involved in biopharmaceutical manufacturing, the cost to manufacture biologics is generally higher than traditional small molecule chemical compounds, and the manufacturing process is less reliable and is more difficult to reproduce, and this is particularly true with respect to our product candidates. The application of new regulatory guidelines or parameters, such as those related to control strategy testing, may also adversely affect our ability to manufacture our product candidates in a compliant and cost-effective manner or at all.

We are investing early in building world class capabilities in key areas of manufacturing sciences and operations, including development of our ex vivo and in vivo cell engineering platforms, product characterization, and process analytics from the time candidates are in early research phases. Our investments also include scaled research solutions, scaled infrastructure, and novel technologies to improve efficiency, characterization, and scalability of manufacturing. However, we have limited experience in

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managing the manufacturing processes necessary for making cell and gene therapies. We cannot be sure that the manufacturing processes that we use, or the technologies that we incorporate into these processes, will result in viable or scalable yields of ex vivo and in vivo cell engineering product candidates that will be safe and effective and meet market demand.

A key part of our strategy is operating our own manufacturing facility. Accordingly, in July 2021, we entered into a long-term lease to establish and operate our own current good manufacturing practices (cGMP) manufacturing facility to support our late-stage clinical development and early commercial product candidates across our product portfolio, including with respect to the production of allogeneic CAR T cells, viral vectors, and PSC-derived products. We expect that it will take several years before we are able to begin manufacturing our product candidates at this facility, if we are able to do so at all. Designing and building out our manufacturing facility will be time-consuming and will require significant resources, including a reallocation of certain of our existing financial, human and other resources, including the time and attention of our senior management. In addition, given the volatility in the costs of building materials, building out our manufacturing facility may be more expensive than we expect. We do not have experience as a company in developing a manufacturing facility, and we may experience unexpected costs or delays or be unsuccessful in developing our internal manufacturing capability in time to support registration-enabling clinical trials of our product candidates or at all. In order to build out the facility, we will need to engage third-party service providers and obtain equipment and third-party technology necessary to manufacture our product candidates at the facility; however, we may not be able to negotiate agreements with third parties or access necessary technologies on commercially reasonable terms or at all. Moreover, there is no guarantee that the industrial space that we are leasing to develop our manufacturing facility will not change ownership over the term of the lease or be subject to additional zoning or other restrictions, and that, in such an event, we will be able to continue to build or operate the facility without further delay or cost. In addition, operating our facility will require us to continue to hire and retain experienced scientific, quality control, quality assurance, and manufacturing personnel. As described elsewhere in these Risk Factors, competition for qualified personnel in the biotechnology and pharmaceutical industries is intense, and if we fail to attract qualified personnel or retain and motivate our current personnel, we will not be able to operate our facility, and our business and future growth prospects would be harmed.

Until we are able to begin manufacturing our product candidates at our facility, we will rely on third-party contract manufacturers to manufacture our product candidates for preclinical studies and clinical trials. Once we have completed the build-out of our manufacturing facility, we will be required to transition manufacturing processes and know-how of certain of our product candidates from our contract development and manufacturing organizations (CDMOs) to our facility. To date, we and our CDMOs have limited experience in the technology transfer of manufacturing processes from us to our CDMOs. Transferring manufacturing processes and know-how is complex and involves review and incorporation of both documented and undocumented processes that may have evolved over time. In addition, transferring production to our facility may require utilization of new or different processes to meet the requirements of our facility. Additional studies may also need to be conducted to support the transfer of certain manufacturing processes and process improvements. We will not know with certainty whether all relevant know-how and data has been adequately incorporated into the manufacturing process being conducted at our facility until the completion of studies and evaluations intended to demonstrate the comparability of material previously produced by our CDMOS with that generated by our facility.

Operating our manufacturing facility will require us to comply with complex regulations. Moreover, our manufacturing facility, and any future commercial manufacturing facilities we may operate, will require FDA or comparable foreign regulatory authority approval, which we may not obtain in time to support registration-enabling clinical trials for our product candidates, if at all. Even if approved, we would be subject to ongoing periodic unannounced inspections by the FDA, the Drug Enforcement Administration, corresponding state agencies, and comparable foreign regulatory authorities to ensure strict compliance with cGMP, current good tissue practices (cGTPs), and other government regulations. We also may make changes to our manufacturing process at various points during development, and even after commercialization, for various reasons, such as to control costs, achieve scale, decrease processing time, increase manufacturing success rate, or for other reasons. Such changes carry the risk that they will not achieve their intended objectives, and any of these changes could cause our product candidates to perform differently and affect the results of any of our then-ongoing clinical trials or future clinical trials, or the performance of the product, once commercialized. In some circumstances, changes in the manufacturing process may require us to perform comparability studies and to collect additional data from patients prior to undertaking more advanced clinical trials. For instance, changes in our process during the course of clinical development may require us to show the comparability of the product used in earlier clinical phases or at earlier portions of a trial to the product used in later clinical phases or later portions of the trial. We may also make further changes to our manufacturing process before or after commercialization, and such changes may require us to show the comparability of the resulting product to the product used in the clinical trials using earlier processes. We may be required to collect additional clinical data from any modified process prior to obtaining marketing approval for the product candidate produced with such modified process. If clinical data are not ultimately comparable to that seen in the earlier trials in terms of safety or efficacy, we may be required to make further changes to our process or undertake additional clinical testing, either of which would significantly delay the clinical development or commercialization of the relevant product candidate.

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Furthermore, if contaminants are discovered in our supply of product candidates or in our manufacturing facility, or any future manufacturing facilities, such supply may have to be discarded and our manufacturing facilities may need to be closed for an extended period of time to investigate and remedy the contamination. We cannot guarantee that any stability or other issues relating to the manufacture of our product candidates will not occur in the future. We may not be able to manufacture our product candidates as a result of not meeting regulatory requirements and may not be able to scale up or scale out our manufacturing to meet market demand. Any failure or delay in the development of our manufacturing capabilities could adversely impact the development and potential commercialization of our product candidates.

We may encounter difficulties in managing our growth as we continue to expand our development and regulatory capabilities, which could disrupt our operations.

We have experienced rapid growth since our inception in July 2018. As of December 31, 2021, we had 383 full-time employees and three part-time employees. We expect continued growth in the number of our employees and the scope of our operations, particularly as we advance our IND-enabling studies, establish regulatory, quality, and clinical operations, and continue to establish supply chain logistics and manufacturing. To manage our anticipated future growth, we plan to continue to implement and improve our managerial, operational, and financial systems, expand our facilities, and continue to recruit and train additional qualified personnel. Due to our limited financial resources and the complexity involved in managing a company with such anticipated growth, we may not be able to effectively manage the expansion of our operations or recruit and train additional qualified personnel. In addition, we have limited experience in managing the manufacturing processes necessary for making cell and gene therapies. The expansion of our operations will be costly and may divert our management and business development resources. For example, members of management will have significant added responsibilities in connection with effecting and managing our growth, including identifying, recruiting, integrating, maintaining, and motivating current and future employees, effectively managing our internal development efforts, including the clinical and regulatory (e.g., FDA) review process, while complying with our contractual obligations to third parties, and maintaining and improving our operational, financial, and management controls, reporting systems, and procedures. In addition, as we grow, we may be required to rely more heavily on third-party service providers, advisors, and consultants to provide certain services, including strategic, financial, business development, and research and development services, as well as with respect to certain aspects of our regulatory approval affairs and manufacturing activities. We cannot guarantee that such third parties will be available to us on a timely basis when needed, or that we will be able to find and engage qualified replacements if required. Our inability to successfully manage our growth could delay the execution of our business plans or disrupt our operations.

We may expend our limited resources to pursue a particular product candidate or indication and fail to capitalize on product candidates or indications that may be more profitable or for which there is a greater likelihood of success.

Because we have limited financial and managerial resources, we focus on research programs, therapeutic platforms, and product candidates that we identify for specific indications. Additionally, we have contractual commitments under our collaboration agreements to use commercially reasonable efforts to develop certain programs and, thus, do not have unilateral discretion to vary from such agreed upon efforts. In addition, we have contractual commitments to conduct certain development plans, and thus may not have discretion to modify such development plans, including clinical trial designs, without agreement from our collaboration partners. As a result, we may forego or delay pursuit of opportunities with other therapeutic platforms or product candidates or for other indications that later prove to have greater commercial potential. Our resource allocation decisions may cause us to fail to capitalize on viable commercial products or profitable market opportunities. Our spending on current and future research and development programs, therapeutic platforms, and product candidates for specific indications may not yield any commercially viable products. If we do not accurately evaluate the commercial potential or target market for a particular product candidate, we may relinquish valuable rights to that product candidate through collaboration, licensing, or other royalty arrangements in cases in which it would have been more advantageous for us to retain sole development and commercialization rights.

The use of human stem cells exposes us to a number of risks in the development of our human stem cell-derived products, including an inability to obtain suitable donor material from eligible and qualified human donors, restrictions on the use of human stem cells, as well as ethical, legal, and social implications of research on the use of stem cells, any of which could prevent us from completing the development of or commercializing and gaining acceptance for our products derived from human stem cells.

We use human stem cells in our research and development, including induced PSCs (iPSCs) and embryonic stem cells (ESCs), and one or more of our ex vivo cell engineering product candidates may be derived from human stem cells. The use of such cells in our research, or as starting cell lines in the manufacture of one or more of our product candidates, exposes us to a number of risks. These risks include difficulties in securing sufficient and viable stem cells as starting material, recruiting patients for our future clinical trials, as well as managing a multitude of legal and regulatory restrictions on the sourcing and use of these cells. In particular, in some states, use of embryonic tissue as a source of stem cells is prohibited and many research institutions have adopted policies regarding the ethical use of human embryonic tissue. If these policies or restrictions have the effect of limiting the scope of research we can conduct using stem cells, our ability to develop our ex vivo cell engineering product candidates may be significantly impaired, which could

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have an adverse material effect on our business. Further, the use of stem cells generally, and embryonic stem cells in particular, has social, legal, and ethical implications. Certain political and religious groups continue to voice opposition to the use of human stem cells in drug research, development, and manufacture. Adverse publicity due to ethical and social controversies surrounding the use of stem cells could lead to negative public opinion, difficulties enrolling patients in our clinical trials, increased regulation, and stricter policies regarding the use of such cells, which could harm our business and may limit market acceptance of any of our product candidates that may receive regulatory approval. In addition, clinical experience with stem cells, including iPSCs and ESCs, is limited. We are not aware of any products that utilize iPSCs or ESCs as a starting material that have received marketing approval from the FDA or a comparable foreign regulatory authority. Therefore, patients in our clinical trials may experience unexpected side effects, and we may experience unexpected regulatory delays prior to or after regulatory approval, if approval were to be granted.

Furthermore, manufacturing and development of our ex vivo stem cell-derived and allogeneic T cell-derived product candidates will rely on our ability to obtain suitable donor material from eligible and qualified human donors. If we are unable to obtain sufficient quantities of suitable donor material, or if we are unable to obtain such material in a timely manner, we may experience delays in manufacturing our ex vivo product candidates, which would harm our ability to conduct future clinical trials for or to commercialize these product candidates. Moreover, if the consent, authorization, or process for the donation of those materials is not obtained or conducted in accordance with applicable legal, ethical, and regulatory requirements, we could face delays in the clinical testing and approval of these product candidates, or, potentially, we could face claims by such human donors, which could expose us to damages and reputational harm.

The ongoing COVID-19 pandemic could materially and adversely affect our preclinical studies and development, our manufacturing capabilities, any clinical trials we may commence, and our business, financial condition, and results of operations.

As a result of the COVID-19 pandemic, or similar pandemics, and related “shelter in place” orders and other public health guidance measures, we have experienced and may in the future experience disruptions that could materially and adversely impact our preclinical studies and development, any clinical trials we may commence, and our business, financial condition, and results of operations. In response to the spread of COVID-19, we have limited operations in our executive offices, with our administrative employees primarily continuing their work outside of our offices, and have taken other precautionary measures, including the periodic testing of our on-site employees. We also established a cross-functional task force and implemented business continuity plans designed to address and mitigate the impact of the ongoing COVID-19 pandemic on our business.

Potential disruptions to our preclinical development efforts resulting from the ongoing COVID-19 pandemic may include the following:

In addition, we have experienced, and we and our service providers or vendors may continue to experience, delays in the procurement of, or an inability to procure, certain laboratory supplies required for the conduct of our research and preclinical activities, such as cell culture plasticware and single use containers, as a result of factors related to the ongoing COVID-19 pandemic, including increased demand due to ramp up of COVID-19 research and manufacturing, government-mandated allocation of materials for such research and manufacturing, insufficient manufacturing capacity, and delays by CDMOs in increasing manufacturing capacity to address increased demand. The ongoing COVID-19 pandemic may also adversely affect our manufacturing capabilities. For example, we may experience delays or otherwise experience difficulties in building out and operationalizing our internal manufacturing facility and obtaining key materials, consumables, and equipment necessary to manufacture our product candidates.

In addition, if and when we commence clinical trials for any of our product candidates, we may experience potential delays or disruptions of clinical trial-related activities as a result of the ongoing COVID-19 pandemic, including as a result of the following:

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The COVID-19 global pandemic continues to rapidly evolve. Although many countries, including certain countries in Europe and the United States, have re-opened, rises in new cases, including as the result of newly identified COVID-19 variants, have caused certain countries, states, and localities to re-initiate restrictions. The extent to which the COVID-19 pandemic may affect our preclinical studies, future clinical trials, business, financial condition, and results of operations will depend on future developments, which are highly uncertain and cannot be predicted at this time, such as the geographic spread of the disease, the duration of the pandemic, travel restrictions, actions to contain the pandemic or reduce its impact in the United States and other countries, such as required social distancing, quarantines, lock-downs, business closures, or business disruptions, and the effectiveness of actions taken in the United States and other countries to contain and treat the disease. Additionally, we are unable to predict if and when a different pandemic may occur, and if so, whether it would have similar or different impacts on our business, financial condition, or share price. Future developments in these and other areas present material uncertainty and risk with respect to our preclinical activities, clinical trials, business, financial condition, and results of operations.

Negative public opinion and increased regulatory scrutiny of research and therapies involving gene editing or other ex vivo or in vivo cell engineering technologies may damage public perception of our product candidates or adversely affect our ability to conduct our business or obtain regulatory approvals for our product candidates.

Certain aspects of our cell engineering platforms rely on the ability to edit genes. Public perception may be influenced by claims that gene editing is unsafe, and products incorporating gene editing may not gain the acceptance of the public or the medical community. In particular, our success will depend upon physicians specializing in diseases that our product candidates are designed to target prescribing our product candidates as treatments in lieu of, or in addition to, existing, more familiar treatments for which greater clinical data may be available. Any increase in negative perceptions of gene editing may result in fewer physicians prescribing our treatments or may reduce the willingness of patients to utilize our treatments or participate in clinical trials of our product candidates. In addition, given the novel nature of ex vivo and in vivo cell engineering technologies, governments may impose import, export, or other restrictions in order to retain control or limit the use of such technologies. Increased negative public opinion or more restrictive government regulations, either in the United States or internationally, would have a negative effect on our business or financial condition and may delay or impair the development and commercialization of our product candidates or demand for such product candidates.

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Risks Related to the Development and Clinical Testing of Our Product Candidates

We must successfully progress our product candidates through extensive preclinical studies and clinical trials in order to obtain regulatory approval to market and sell such product candidates. Even if we obtain positive results in preclinical studies of a product candidate, these results may not be predictive of the results of future preclinical studies or clinical trials.

To obtain the requisite regulatory approvals to market and sell any of our product candidates, we or any future collaborator for such product candidate must demonstrate through extensive preclinical studies and clinical trials that the product candidate is safe, pure, and potent in humans. Before an IND can be submitted to the FDA and become effective, which is a prerequisite for conducting clinical trials on human subjects, a product candidate must successfully progress through extensive preclinical studies, which include preclinical laboratory testing, animal studies, and formulation studies conducted in accordance with good laboratory practices (GLP).

Success in preclinical studies does not ensure that later preclinical studies or clinical trials will be successful. A number of companies in the biotechnology and pharmaceutical industries have suffered significant setbacks in clinical trials, even after positive results in preclinical studies. These setbacks have been caused by, among other things, preclinical findings made while clinical trials were underway and safety or efficacy observations made during the course of clinical trials, including previously unreported adverse events. The design of a clinical trial can determine whether its results will support approval of a product, and flaws in the design of a clinical trial may not become apparent until the clinical trial is well advanced. In addition, preclinical and clinical data are often susceptible to varying interpretations and analyses. Notwithstanding any potential promising results in earlier studies, we cannot be certain that we will not face similar setbacks. In addition, the results of our preclinical animal studies, including our non-human primate studies, may not be predictive of the results of subsequent clinical trials on human subjects. Product candidates may fail to show the desired pharmacological properties or safety and efficacy traits in clinical trials despite having successfully progressed through preclinical studies.

If we fail to obtain positive results in preclinical studies or clinical trials of any product candidate, the development timeline and regulatory approval and commercialization prospects for that product candidate, and, correspondingly, our business and financial prospects, would be negatively impacted.

All of our product candidates are in preclinical development, and none have commenced clinical development. Preclinical and clinical drug development is a lengthy and expensive process with uncertain timelines and uncertain outcomes. If preclinical studies or clinical trials of any of our product candidates are prolonged or delayed, we may be unable to obtain required regulatory approvals and commercialize such product candidates on a timely basis or at all.

Preclinical studies and clinical trials are expensive, can take many years to complete, and their outcomes are inherently uncertain. Failure can occur at any time during preclinical or clinical development. Product candidates in later-stage clinical trials may fail to produce the same results as observed in earlier trials or fail to show the desired safety and efficacy traits despite having progressed through preclinical studies and earlier clinical trials. Our future clinical trials may not be successful.

Applicable laws and regulations require us to test our product candidates in animals before initiating clinical trials involving humans. We may experience delays or experience difficulty completing studies of our product candidates in animals for various reasons. For example, due to global supply chain issues caused by global geo-political, economic, and other factors beyond our control, including the ongoing COVID-19 pandemic, as described elsewhere in these Risk Factors, we have experienced and may continue to experience difficulty in accessing animal models, specifically non-human primate models, for the preclinical evaluation of our product candidates. In addition, animal testing activities have been the subject of controversy and adverse publicity. Animal rights groups and other organizations and individuals have attempted to stop animal testing activities by pressing for legislation and regulation in these areas and by disrupting these activities through protests and other means. To the extent the activities of these groups are successful, our research and development activities may be interrupted, delayed, or become more expensive.

We are required to submit an IND to the FDA with respect to each product candidate prior to commencing a clinical trial for such product candidate. While we plan to submit INDs for each of our product candidates, we may not be able to submit such INDs in accordance with our expected timelines for various reasons, including due to:

Moreover, we cannot guarantee that submission of an IND for a product candidate will result in the FDA or comparable foreign regulatory authorities allowing clinical trials of that product candidate to commence in accordance with our timelines or expectations

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or at all. For example, the FDA may accept an IND submission for a product candidate but place clinical trials of such product candidate on hold pending the results of additional testing or the development of additional assays. Additionally, even if regulatory authorities agree with the design and implementation of the clinical trials set forth in an IND, we cannot guarantee that such regulatory authorities will not change their requirements in the future. These considerations also apply to new clinical trials we may submit as amendments to existing INDs.

To date, we have not commenced any clinical trials. We do not know whether planned clinical trials will begin on time, need to be redesigned, enroll patients on time, or be completed on schedule, if at all. Clinical trials may be delayed, suspended, or terminated for a variety of reasons, including the following:

In addition, disruptions caused by the COVID-19 pandemic, to the extent it is still ongoing when we initiate our planned clinical trials, may increase the likelihood that we encounter difficulties or delays in initiating, enrolling, conducting, or completing such clinical trials, as described elsewhere in these Risk Factors.

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Additionally, some of our trials may be open-label trials in which both the patient and investigator know whether the patient is receiving the investigational product candidate or an existing approved therapy. Open-label clinical trials are subject to various limitations that may exaggerate any therapeutic effect, as patients in open-label clinical trials are aware when they are receiving treatment. In addition, open-label clinical trials may be subject to an “investigator bias,” where those assessing and reviewing the physiological outcomes of patients in the clinical trials are aware of which patients have received the experimental treatment and may interpret the information of this group more favorably given this knowledge. Therefore, it is possible that positive results observed in open-label trials will not be replicated in later placebo-controlled trials.

Clinical trials must be conducted in accordance with the FDA and comparable foreign regulatory authorities’ legal requirements, regulations and guidelines and are subject to oversight by these governmental authorities and IRBs or Ethics Committees at the medical institutions where the clinical trials are conducted. We could encounter delays if a clinical trial is suspended or terminated by us, by the IRBs or Ethics Committees of the institutions at which such trial is being conducted, by the Data Review Committee or Data Safety Monitoring Board for such trial, or by the FDA or comparable foreign regulatory authorities. Such authorities may impose such a suspension or termination, including following an inspection of clinical trial operations or a clinical trial site, due to a number of factors, including failure to conduct the clinical trial in accordance with regulatory requirements or our clinical protocols, unforeseen safety issues or adverse side effects, failure to demonstrate a benefit from use of the product candidate being tested, changes in governmental regulations or administrative actions, or lack of adequate funding to continue the clinical trial. In addition, such authorities may impose a clinical hold on a product candidate due to unforeseen safety issues or adverse side effects that may be associated with a therapeutic or therapeutic candidate being developed by us or a third party if regulators deem our product candidate to have the potential for comparable side effects or risks as such therapeutic or therapeutic candidate because of biologic, mechanistic, sourcing, or other similarities. If we experience delays in completing, or are required to terminate, any clinical trial of our product candidates, the commercial prospects of the relevant product candidates will be harmed, and our ability to generate product revenues from these product candidates will be delayed. In addition, any delays in completing our clinical trials will increase our costs, delay our ability to obtain regulatory approval for the relevant product candidate, and jeopardize our ability to commence product sales and generate revenues. Significant clinical trial delays could also allow our competitors to bring products to market before we do or shorten any periods during which we have the exclusive right to commercialize our product candidates, which may impair our ability to commercialize our product candidates and harm our business and results of operations.

Furthermore, as described elsewhere in these Risk Factors, we will rely on CROs and clinical trial sites to ensure the proper and timely conduct of our clinical trials in compliance with good clinical practices (GCP) requirements. While we will enter into agreements governing their conduct, we will have limited influence over their actual performance. To the extent the CROs and clinical trial sites fail to timely and successfully enroll patients in our clinical trials, fail to conduct such clinical trials in accordance with GCP, or experience significant delays in the execution of trials, including delays in achieving full enrollment or clinical trial data collection and analysis, we may experience program delays, incur additional costs, or both, which may harm our business. In addition, we may experience delays and incur additional costs with respect to clinical trials that we conduct in countries outside the United States, including as a result of increased shipment and distribution costs, compliance with additional regulatory requirements, and the engagement of non-United States. CROs, and may also be exposed to risks associated with clinical investigators who are unknown to the FDA, and different standards of diagnosis, screening, and medical care.

Our future clinical trials may fail to demonstrate substantial evidence of the safety and efficacy of our product candidates, including any future product candidates, which would prevent, delay or limit the scope of regulatory approval and commercialization of such product candidates.

To obtain the requisite regulatory approvals to market and sell any of our product candidates and any other future product candidates, we must demonstrate through clinical trials that our product candidates are safe and effective for use in each targeted indication. Clinical testing is expensive and can take many years to complete, and its outcome is inherently uncertain. Failure can occur at any time during the clinical development process. Most product candidates that begin clinical trials are never approved by regulatory authorities for commercialization. We may be unable to establish clinical endpoints that applicable regulatory authorities would consider clinically meaningful.

Further, the process of obtaining regulatory approval is expensive, often takes many years following the commencement of clinical trials, and can vary substantially based upon the type, complexity, and novelty of the product candidates involved, as well as the target indications, patient population, and regulatory authority involved. Prior to obtaining approval to commercialize our current or future product candidates in the United States or abroad, we or our potential future collaborators must demonstrate with substantial evidence from adequate and well-controlled clinical trials, and to the satisfaction of the FDA or comparable foreign regulatory authorities, that such product candidates are safe and effective for their intended uses.

Clinical trials that we conduct may not demonstrate the efficacy and safety necessary to obtain regulatory approval to market our product candidates. In some instances, there can be significant variability in safety or efficacy results between different clinical trials of the same product candidate due to numerous factors, including changes in trial procedures set forth in protocols, differences in

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the size and type of the patient populations, changes in and adherence to the clinical trial protocols, and the rate of dropout among clinical trial participants. If the results of our clinical trials are inconclusive with respect to the efficacy of our product candidates, if we do not meet the clinical endpoints with statistical and clinically meaningful significance, or if there are safety concerns associated with our product candidates, we may experience delays in obtaining marketing approval, or we may not obtain approval at all. Additionally, any safety concerns observed in any one of our clinical trials for a product candidate in our targeted indications could limit the prospects for regulatory approval of such product candidate in those and other indications.

Even if we successfully complete any future clinical trials, clinical data are often susceptible to varying interpretations and analyses. We cannot guarantee that the FDA or comparable foreign regulatory authorities will interpret the results as we do, and more trials could be required before we submit our product candidates for approval. Even if positive results are observed in clinical trials, we cannot guarantee that the FDA or comparable foreign regulatory authorities will view our product candidates as having efficacy. Further, the FDA or comparable foreign regulatory authorities may not agree with our manufacturing strategy or may not find comparability between our clinical trial product candidates and proposed commercial product candidates, which may result in regulatory delays or a need to perform additional clinical studies. Moreover, clinical trial results that may be acceptable to support approval of a certain scope in one jurisdiction may be deemed inadequate to support regulatory approval, or may only be deemed sufficient to support a narrower scope of approval, in other jurisdictions. If the FDA or comparable foreign regulatory authorities determine that our clinical trial results are not adequate to support approval of a marketing application, we may experience delays in obtaining, or fail to obtain, approval of our product candidates, or we may be required to expend significant additional resources, which may not be available to us, to conduct additional trials in support of potential approval of our product candidates. Even if regulatory approval is obtained for a product candidate, the terms of such approval may limit the scope and use of the specific product candidate, which may also limit its commercial potential.

Our product candidates may have serious adverse, undesirable, or unacceptable side effects or other properties that may delay or prevent marketing approval. If a product candidate receives regulatory approval, and such side effects are identified following such approval, the commercial profile of any approved label may be limited, or we may be subject to other significant negative consequences following such approval.

Our product candidates may cause undesirable side effects, which could cause us or regulatory authorities to interrupt, delay, or halt our future clinical trials and could result in a more restrictive label or the delay or denial of regulatory approval by the FDA or comparable foreign authorities. We have not commenced clinical trials for any of our product candidates, and we do not have any clinical data or other information that would enable us to fully anticipate their side effects. Accordingly, we may observe unexpected side effects or higher levels of known side effects in clinical trials of our product candidates, including adverse events known to occur in the same classes of therapeutics. These may include, among others, infusion reaction, cytokine release syndrome (CRS), graft-versus-host disease (GvHD), neurotoxicities, and certain cancers.

Results of our clinical trials could reveal a high and unacceptable severity and prevalence of these or other side effects associated with our product candidates. In such an event, clinical trials of such product candidates could be suspended or terminated, and the FDA or comparable foreign regulatory authorities could order us to cease further development of or deny approval of such product candidates for any or all targeted indications. The occurrence of such side effects could negatively affect our ability to recruit and enroll patients in our clinical trials, or the ability of enrolled patients to complete the clinical trials or result in product liability claims. Any of these occurrences may harm our business, financial condition, and prospects significantly.

Further, clinical trials by their nature utilize only a sample of the potential patient population. With a limited number of patients and limited duration of exposure to our product candidates, rare and severe side effects of our product candidates may not be apparent during early clinical trials and may only be uncovered once a significantly larger number of patients have been exposed to the product candidate, including during later-stage clinical trials or following commercialization.

In the event that any of our product candidates receives marketing approval and we or others later identify undesirable or unacceptable side effects caused by such products, a number of potentially significant negative consequences could result, including:

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Any of these events could prevent us or our potential future partners from achieving or maintaining market acceptance of the affected product or could substantially increase commercialization costs and expenses, which in turn could delay or prevent us from generating significant revenue from the sale of any products.

Interim, topline, or preliminary data from our preclinical studies or future clinical trials that we may announce or publish from time to time may change as more patient data become available or as we make changes to our manufacturing processes. These data are subject to audit and verification procedures that could result in material changes in the final data.

From time to time, we may publicly disclose interim, topline, or preliminary data from our preclinical studies or future clinical trials, which are based on a preliminary analysis of then-available data, and the results and related findings and conclusions are subject to change following a more comprehensive review of the data related to the particular study or trial. We also make assumptions, estimations, calculations, and conclusions as part of our analyses of data, and we may not have received or had the opportunity to fully and carefully evaluate all data at the time of our initial disclosure of data. Further, modifications or improvements to our manufacturing processes for a product candidate may result in changes to its characteristics or behavior that could cause the product candidate to perform differently and affect the results of our ongoing clinical trials of such product candidate. As a result, the topline results that we report may differ from future results of the same studies, or different conclusions or considerations may qualify such results once additional data have been received and fully evaluated. Topline data also remain subject to audit and verification procedures that may result in the final data being materially different from the preliminary data we previously disclosed. As a result, topline data should be viewed with caution until the final data are available. Similarly, preliminary or interim data from clinical trials are subject to the risk that one or more of the clinical outcomes may materially change as patient enrollment continues and more patient data become available. Adverse differences between preliminary or interim data and final data could significantly harm our business prospects. Additionally, disclosure of preliminary or interim data by us or our competitors, with respect to clinical trials of their product candidates, could result in volatility in the price of our common stock.

Further, others, including regulatory authorities, may not accept or agree with our assumptions, estimates, calculations, conclusions, or analyses or may interpret or weigh the importance of data differently, which could impact the value of the particular program, the approvability or commercialization of the particular product candidate, and our company in general. If the interim, topline, or preliminary data that we report differ from actual results, or if others, including regulatory authorities, disagree with the conclusions reached, our ability to obtain approval for and commercialize our potential product candidates may be harmed, which could harm our business, operating results, prospects, or financial condition.

The manufacture of our product candidates is complex. We or our third-party CDMOs may encounter difficulties in production, which could delay or entirely halt our or their ability to supply our product candidates for clinical trials or, if approved, for commercial sale.

Our product candidates are considered to be biologics, and the process of manufacturing biologics is complex and requires significant expertise and capital investment, including the development of advanced manufacturing techniques and process controls. In July 2021, we entered into a long-term lease to establish and operate our own cGMP manufacturing facility to support our late-stage clinical development and early commercial product candidates across our product portfolio. However, we expect that it will take several years before we are able to begin manufacturing our product candidates at this facility, if at all. We currently rely, and expect for some period of time to continue to rely, on third-party CDMOs for the manufacture of our product candidates for preclinical and clinical studies. To date, we and our CDMOs have limited experience in manufacturing of cGMP batches of our product candidates. Our CDMOs and, once we begin to operate our manufacturing facility, we, must comply with cGMPs and other regulations and guidelines applicable to the manufacturing of biologics for use in clinical trials and, if approved, commercial sale. To date, we have not scaled the manufacturing processes with respect to our product candidates for later-stage clinical trials and commercialization. Larger-scale manufacturing will require the development of new processes, including for the removal of impurities that are a normal byproduct of the manufacturing process. The nature of our product candidates requires the development of novel manufacturing

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processes and analytical technologies, which could cause delays in the scaling of manufacturing, as well as greater costs that could negatively impact the financial viability of our product candidates. We cannot be sure that the manufacturing processes employed by our CDMOs or the technologies that our CDMOs incorporate into our manufacturing processes will result in viable or scalable yields of ex vivo and in vivo cell engineering product candidates that will be safe and effective and, if approved, meet market demand.

Once we have completed the build-out of our manufacturing facility, we will be required to transition manufacturing processes and know-how of certain of our product candidates from our CDMOs to our facility. To date, we and our CDMOs have limited experience in the technology transfer of manufacturing processes from us to our CDMOs. Transferring manufacturing processes and know-how is complex and involves review and incorporation of both documented and undocumented processes that may have evolved over time. In addition, transferring production to our facility may require utilization of new or different processes to meet the requirements of our facility. Additional studies may also need to be conducted to support the transfer of certain manufacturing processes and process improvements. We will not know with certainty whether all relevant know-how and data has been adequately incorporated into the manufacturing process being conducted at our facility until the completion of studies and evaluations intended to demonstrate the comparability of material previously produced by our CDMOs with that generated by our facility.

The process of manufacturing our biologic product candidates is extremely susceptible to product loss due to contamination, equipment failure, or improper installation or operation of equipment, vendor or operator error, inconsistency in yields, variability in product characteristics, and difficulties in scaling the production process. Even minor deviations from normal manufacturing processes could result in reduced production yields, product defects, and other supply disruptions. If microbial, viral, or other contaminations are discovered in our product candidates or in the manufacturing facilities in which our product candidates are made, this could lead to withdrawal of our products from clinical trials and, if approved, the market, and such manufacturing facilities may need to be closed for an extended period of time to investigate and remedy the contamination. Moreover, if the FDA or comparable foreign regulatory authorities determine that we or our CDMOs are not in compliance with applicable laws and regulations, including those governing cGMPs, the FDA or comparable foreign regulatory authority may not approve a BLA or comparable foreign marketing authorization until the deficiencies are corrected or we replace the manufacturer in our applications with a manufacturer that is in compliance. If we or our CDMOs fail to comply with applicable regulatory requirements, we may ultimately be unable to manufacture our product candidates.

Any adverse developments affecting manufacturing operations for any of our product candidates for which we may obtain approval, may result in shipment delays, inventory shortages, lot failures, product withdrawals or recalls, or other supply interruptions. We may also have to take inventory write-offs and incur other charges and expenses for products that fail to meet specifications as a result of defects or storage over an extended period of time, undertake costly remediation efforts, or seek more costly manufacturing alternatives. As part of our process development efforts, we also may make changes to our manufacturing processes at various points during development for various reasons, such as to control costs, achieve scale, decrease processing time, increase manufacturing success rate, or other reasons. Such changes may not achieve their intended objectives, and any of these changes could cause our product candidates to perform differently and affect the results of our future clinical trials. In some circumstances, changes in the manufacturing process for a product candidate may require us to perform comparability studies and collect additional data from patients prior to undertaking more advanced clinical trials.

Given the complexities associated with manufacturing our product candidates, our ability to successfully conduct clinical trials and ultimately commercialize our product candidates will depend in part on our ability to attract, motivate, and retain highly-skilled personnel with significant expertise in manufacturing biologics that can effectively and timely manage and conduct our manufacturing operations. We and our CDMOs face intense competition to attract, motivate, and retain qualified personnel. If we or our CDMOs are unable to attract, motivate, and retain qualified personnel to conduct and manage our manufacturing operations, we may experience delays in manufacturing our product candidates, which could materially harm our ability to conduct our clinical trials or commercialize our product candidates in a timely manner or at all and could harm our business.

We are exposed to a number of risks related to the supply chain for the materials required to manufacture our product candidates.

Manufacturing our product candidates is highly complex and requires sourcing of specialty materials. Many of the risks associated with the complexity of manufacturing our final product candidates are applicable to the manufacture and supply of the raw materials required to make such product candidates. In particular, these raw materials are subject to inconsistency in yields, variability in characteristics, contamination, difficulties in scaling the production process, and defects. Similar minor deviations in the manufacturing process for these raw materials could result in supply disruption and reduced production yields for our final product candidates. In addition, we rely on third parties for the supply of these materials, which, exposes us to risks associated with dependence on third parties, as described elsewhere in these Risk Factors.

We rely on obtaining suitable donor material from eligible and qualified donors for the manufacture of product candidates from our ex vivo cell engineering platform. We may not be able to obtain sufficient quantities donor material in a timely manner or at all, including due to an inability to find donors who meet the eligibility criteria or geo-political, economic, and other factors beyond our control, including the ongoing COVID-19 pandemic, that may prevent individuals from donating blood. If we are unable to obtain

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sufficient quantities of suitable donor material, or if we are unable to obtain such material in a timely manner, we may experience delays in manufacturing our ex vivo product candidates, which would harm our ability to conduct future clinical trials for or to commercialize these product candidates.

In addition, our manufacturing processes require many reagents, which are drug substance intermediates used in our manufacturing processes to bring about chemical or biological reactions, and other specialty materials, consumables, and equipment, some of which are manufactured or supplied by small companies with limited resources and experience with respect to supporting clinical or commercial biologics production. We currently depend on a limited number of vendors for certain materials and equipment used in the manufacture of our product candidates. Some of these suppliers may not have the capacity to support manufacturing of products under cGMP or may otherwise be ill-equipped to support our needs. Reagents and other key materials from these suppliers may have inconsistent attributes and introduce variability into our manufactured product candidates, which may contribute to variable patient outcomes and possible adverse events. We also do not have supply contracts with many of these suppliers and may not be able to enter into supply contracts with them on acceptable terms or at all. Accordingly, we may experience delays in receiving key materials and equipment to support clinical or commercial manufacturing.

For some of these reagents, materials, and equipment, we rely and may in the future rely on sole source vendors or a limited number of vendors. We may be unable to continue to source reagents, materials, or equipment from any of these suppliers for various reasons, including due to regulatory actions or requirements affecting a supplier, adverse financial or other strategic developments experienced by a supplier, labor disputes or shortages, unexpected demands, or quality issues. Additionally, due to global geo-political, economic, and other factors beyond our control, including the ongoing COVID-19 pandemic, there has been, and there may continue to be, a shortage of key materials and equipment that are necessary to manufacture our product candidates, including certain consumables such as bags, flasks, and pipette tips, which could affect our or our contract manufacturers’ ability to obtain the materials and equipment necessary to manufacture our product candidates. If any of the foregoing events were to occur, we may experience delays in manufacturing our product candidates, which would harm our ability to conduct future clinical trials and, if approved, commercialize our product candidates and generate product revenues in a timely manner or at all.

As we continue to develop and scale our manufacturing processes, we expect that we will need to obtain rights to and supplies of certain materials and equipment to be used as part of those processes. We may not be able to obtain rights to such materials on commercially reasonable terms, or at all, and our inability to alter our processes in a commercially viable manner to avoid the use of such materials or equipment or find suitable substitutes would have a material adverse effect on our business. Even if we are able to alter our processes so as to use other materials or equipment, such a change may delay our clinical development or commercialization plans. If such a change occurs for product candidate that is already being tested in clinical trials, the change may require us to perform comparability studies and to collect additional data from patients prior to undertaking more advanced clinical trials.

We will depend on timely and successful enrollment and retention of patients in our clinical trials for our product candidates. If we experience delays or difficulties enrolling or retaining patients in our clinical trials, our research and development efforts and business, financial condition, and results of operations could be materially adversely affected.

Successful and timely initiation and completion of clinical trials will require that we enroll and retain a sufficient number of patients. Any clinical trials we conduct may be subject to delays for a variety of reasons, including as a result of patient enrollment taking longer than anticipated, patient withdrawal, or the occurrence of adverse events. These types of developments could cause us to delay the trial or halt further development of the relevant product candidate.

Our clinical trials will compete with other clinical trials that are in the same therapeutic areas as our product candidates, and this competition will reduce the number and types of patients available to participate in our trials, as some patients who might have opted to enroll in our trials may instead opt to enroll in a trial being conducted by one of our competitors. Moreover, enrolling patients in clinical trials for diseases in which there is an approved standard of care is challenging, as patients will first receive the applicable standard of care. Many patients who respond positively to the standard of care do not enroll in clinical trials. This may limit the number of eligible patients who have the potential to benefit from our product candidates and could extend development timelines or increase costs for our programs. Patients who fail to respond positively to the standard of care treatment would be eligible for clinical trials of our product candidates. However, treatment with prior regimens may render our product candidates less effective in clinical trials.

Because the number of qualified clinical investigators and clinical trial sites is limited, we expect to conduct at least some of our clinical trials at the same clinical trial sites that some of our competitors use, which will reduce the number of patients who are available for our clinical trials at such clinical trial sites.

Patient enrollment in clinical trials depends on many factors, including:

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These factors may make it difficult for us to enroll enough patients to complete our clinical trials in a timely and cost-effective manner. Delays in the completion of any clinical trial of our product candidates will increase our costs, slow down our product candidate development and approval process, and delay or potentially jeopardize our ability to commence product sales and generate revenue. In addition, some of the factors that may cause, or lead to, a delay in the commencement or completion of clinical trials may also ultimately lead to the denial of regulatory approval of our product candidates.

We may become exposed to costly and damaging liability claims, either when testing our product candidates in clinical trials or at the commercial stage, and our product liability insurance may not cover all damages arising from such claims.

We are exposed to potential product liability and professional indemnity risks that are inherent in the research, development, manufacturing, marketing, and use of pharmaceutical products. While we currently have no product candidates for which we have commenced clinical trials or obtained approval for commercial sale, the future use of our product candidates in clinical trials, and the sale of any products for which we may obtain approval in the future, may expose us to liability claims. These claims might be made by patients that use the product, healthcare providers, pharmaceutical companies, or others selling such products. Any claims against us, regardless of their merit, could be difficult and costly to defend and could materially adversely affect the market for our product candidates or any prospects for commercialization of our product candidates.

Although the clinical trial process is designed to identify and assess potential side effects, it is always possible that a drug, even after regulatory approval, may exhibit unforeseen side effects. Physicians and patients may not comply with any warnings that identify known potential adverse effects or patients who should not use our product candidates. If any of our product candidates were to cause adverse side effects during clinical trials or after approval, we may be exposed to substantial liabilities.

We would require significant financial and management resources to defend against any product liability claims, even if we are successful in such defense. Regardless of the merits or eventual outcome, liability claims may result in decreased demand for our product candidates, negative publicity and injury to our reputation, withdrawal of clinical trial participants, initiation of investigations by regulatory authorities, costs to defend the related litigation, diversion of management’s time and our resources, substantial monetary awards to clinical trial participants or patients, product recalls, withdrawals, or labeling, marketing, or promotional restrictions, loss of revenue, exhaustion of any available insurance and our capital resources, inability to commercialize our product candidates, and a decline in our share price.

Although we maintain product liability insurance for our product candidates, it is possible that our liabilities could exceed our insurance coverage. We intend to expand our insurance coverage to include the sale of commercial products if we obtain marketing approval for any of our product candidates. However, we may be unable to maintain insurance coverage at a reasonable cost or obtain insurance coverage that will be adequate to satisfy any liability that may arise. If a successful product liability claim or series of claims is brought against us for uninsured liabilities or in excess of insured liabilities, our assets may not be sufficient to cover such claims, and our business operations could be impaired.

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Risks Related to Our Dependence on Third Parties

We rely on, and expect to continue to expect to rely on, CDMOs to manufacture our product candidates, as well as materials used in the manufacturing of our product candidates. Any failure by a CDMO to produce acceptable materials or product candidates for us or any failure by us or such manufacturer to obtain authorization from the FDA or comparable foreign regulatory authorities or otherwise satisfy regulatory requirements with respect to such manufacturing of our product candidates may delay or impair our ability to initiate or complete our clinical trials, obtain regulatory approvals, or commercialize approved products.

We do not currently own or operate any cGMP manufacturing facilities, nor do we have any in-house cGMP manufacturing capabilities. In July 2021, we entered into a long-term lease to establish and operate our own cGMP manufacturing facility to support our late-stage clinical development and early commercial activities across our product portfolio. Though we plan to begin building out this facility in the near future, we expect that it will take several years before we are able to begin manufacturing our product candidates at this facility, if at all. Until we are able to begin manufacturing our product candidates at our facility, we will rely on CDMOs to manufacture our product candidates for preclinical and clinical testing and will continue to rely on CDMOs to manufacture certain of our product candidates thereafter as part of our manufacturing strategy. A limited number of CDMOs specialize in or have the expertise required to manufacture our product candidates. Moreover, our CDMOs have limited capacity at their facilities and require commitments to secure availability well in advance of manufacturing any products. Additionally, we face competition from other biopharmaceutical companies to secure availability to manufacture our product candidates at these facilities. If the CDMOs on which we rely to manufacture our product candidates do not have sufficient availability at their facilities to manufacture our product candidates in accordance with our timelines or are not otherwise able to meet our expected deadlines, we will experience delays in manufacturing our product candidates. In addition, our CDMOs face intense competition to attract and retain qualified personnel. If our CDMOs are unable to attract, retain, and motivate qualified personnel, they may be unable to perform their obligations in a timely manner, or their performance may be substandard or may not meet our quality requirements, which could cause us to experience delays in manufacturing our product candidates. Any delays in manufacturing our product candidates could materially harm our ability to conduct our clinical trials or commercialize our product candidates in a timely manner or at all and could harm our business.

In addition, we rely on multiple CDMOs to produce sufficient quantities of materials required for the manufacture of our product candidates for preclinical testing and future clinical trials, and intend to continue to rely on such CDMOs for the commercial manufacture of certain of our products, if approved. If we are unable to arrange for such third-party manufacturing sources, or fail to do so on commercially reasonable terms, we may not be able to produce sufficient supply of product candidate or we may be delayed in doing so. Such failure or substantial delay could materially harm our business.

We rely on third parties for biological materials that are used in our discovery and development programs. These materials can be difficult to produce and occasionally have variability from our product specifications. If these materials do not comply with our product specifications, or in the event of any other disruption in the supply of these materials, our business could be materially adversely affected. Although we have control processes and screening procedures, biological materials are susceptible to damage and contamination and may contain active pathogens. We may also have low yield from certain manufacturing batches, which could increase our costs and slow our development timelines. Improper storage of these materials, by us or any third-party suppliers, may require us to destroy some of these materials or product candidates generated using such materials.

Reliance on CDMOs entails risks to which we would not be subject if we manufactured product candidates ourselves, including reliance on the CDMO for regulatory compliance and quality control and assurance, volume production, the possibility of breach of the manufacturing agreement by the CDMO due to factors beyond our control (including a failure to synthesize and manufacture our product candidates in accordance with our product specifications), and the possibility of termination or nonrenewal of the agreement by the CDMO at a time that is costly or damaging to us.

In addition, the FDA and comparable foreign regulatory authorities require that our product candidates be manufactured according to cGMPs and similar foreign standards relating to methods, facilities, and controls used in the manufacturing, processing, and packing of the product candidate, which are intended to ensure that biological products are safe and that they consistently meet applicable requirements and specifications.

Pharmaceutical manufacturers are required to register their facilities and products manufactured at the time of submission of the marketing application and then annually thereafter with the FDA and certain state and foreign agencies. If the FDA or a comparable foreign regulatory authority does not approve our CDMO’s facilities for the manufacture of our product candidates or if it withdraws any such approval in the future, we may need to find alternative manufacturing facilities, which would significantly impact our ability to develop, obtain regulatory approval for, or market our product candidates, if approved, on a timely basis or at all. Any discovery of problems with a product, or a manufacturing or laboratory facility used by us or our strategic partners in connection with manufacturing of that product, may result in restrictions on the product or on the relevant facility, including marketed product recall, suspension of manufacturing, product seizure, or a voluntary withdrawal of the drug from the market. We may have little to no control regarding the occurrence of any such incidents at our CDMOs.

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If we were unable to timely find an adequate replacement for our CDMOs or another acceptable solution, our clinical trials could be delayed, or our commercial activities could be harmed. In addition, because we are dependent on our collaborators, our suppliers, and other third parties for the manufacture, filling, storage, and distribution of our product candidates, we have limited ability to prevent or control manufacturing defects in our products. The sale of products containing such defects could adversely affect our business, financial condition, and results of operations. Any failure by our CDMOs to comply with cGMP or failure to properly scale-up manufacturing processes for our product candidates, or any failure to deliver sufficient quantities of product candidates in a timely manner, could lead to a delay in, or failure to obtain, regulatory approval of any of our product candidates.

Pharmaceutical manufacturers are also subject to extensive post-marketing oversight by the FDA and comparable regulatory authorities in the jurisdictions where a product is marketed, which includes periodic unannounced and announced inspections by the FDA to assess compliance with cGMP requirements. Any failure by one of our CDMOs to comply with cGMP or to provide adequate and timely corrective actions in response to deficiencies identified in a regulatory inspection could result in further enforcement action that could lead to a shortage of products and harm our business, including withdrawal of approvals previously granted, seizure, injunction, or other civil or criminal penalties. The failure of a CDMO to address any concerns raised by the FDA or comparable foreign regulatory authorities could also lead to plant shutdown or the delay or withholding of product approval by the FDA in additional indications or by comparable foreign regulatory authorities in any indication. Certain countries may impose additional requirements on the manufacturing of drug products or drug substances, and on manufacturers, as part of the regulatory approval process for products in such countries. The failure by our CDMOs to satisfy such requirements could impact our ability to obtain or maintain approval of our products in such countries.

If we are unable to obtain sufficient raw and intermediate materials on a timely basis or if we experience other manufacturing or supply interruptions or difficulties, we may be unable to resume supply of such materials or other manufacturing activities within a reasonable time frame and at an acceptable cost or at all, which would adversely affect our business.

The manufacture of our product candidates requires the timely delivery of sufficient amounts of raw and intermediate materials. We purchase, and rely on our CDMOs to purchase, certain of these materials from third-party suppliers in order to produce our product candidates for our preclinical studies. There are a limited number of suppliers of these materials, and we may need to assess alternate suppliers to prevent possible disruption of manufacturing of our product candidates for our preclinical studies, our future clinical trials, and if ultimately approved, commercial sale. We intend to continue to rely on our CDMOs to purchase materials in order to produce product candidates for any clinical trials that we undertake; however, we do not have any control over the process or timing of the acquisition of these materials by our CDMOs. We work closely with our CDMOs and suppliers, as applicable, to ensure the continuity of supply, but cannot ensure that these efforts will always be successful. Further, while we strive to diversify our sources of raw and intermediate materials, in certain instances we acquire raw and intermediate materials from a sole supplier. We cannot be sure that these suppliers will remain in business, or that they will not be purchased by one of our competitors or another company that is not interested in continuing to supply these materials for our intended purpose. In addition, the lead time needed to establish a relationship with a new supplier can be lengthy, and we may experience delays in the event a new supplier must be used. The time and effort to qualify a new supplier could result in additional costs, diversion of resources, or reduced manufacturing yields, any of which would negatively impact our operating results. Although we generally would not begin a clinical trial unless we believe we have a sufficient supply of a product candidate to complete the clinical trial, any significant delay in the supply of a product candidate, or the raw or intermediate material components thereof, for an ongoing clinical trial due to the need to replace a third-party manufacturer could considerably delay completion of our clinical trials, product testing, and potential regulatory approval of our product candidates. While we believe that alternative sources of supply exist where we rely on sole supplier relationships, we cannot ensure that, if needed, we would be able to quickly establish additional or replacement sources for some materials. Moreover, we currently do not have any agreements for the commercial production of these raw or intermediate materials. If any of our product candidates receives regulatory approval and thereafter, we or our CDMOs are unable to purchase these raw or intermediate materials, the commercial launch of our product candidates could be delayed or there could be a shortage in supply of product, which would impair our ability to generate revenues from the sale of such approved product. A reduction or interruption in supply of raw or intermediate materials, and an inability to establish alternative sources for such supply, could adversely affect our ability to manufacture our product candidates or approved products in a timely or cost-effective manner.

We rely, and expect to continue to rely, on third parties, including independent clinical investigators and CROs, to conduct or support our preclinical studies and clinical trials. If these third parties do not successfully carry out their contractual duties, comply with applicable regulatory requirements, or meet expected deadlines, we may not be able to obtain regulatory approval for or commercialize our product candidates and our business could be substantially harmed.

We have relied upon and plan to continue to rely upon third parties, including independent clinical investigators and third-party CROs, to conduct or support our preclinical studies and clinical trials and to monitor and manage data for our ongoing preclinical and clinical programs. We rely or will rely on these parties for execution of our preclinical studies and clinical trials and control only certain aspects of their activities. Even then, we are only able to control such activities to the extent set forth under our contracts with the relevant third parties. Nevertheless, we are responsible for ensuring that each of our preclinical and clinical studies and trials is

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conducted in accordance with the applicable protocol and legal, regulatory, and scientific standards and rules, and our reliance on these third parties does not relieve us of these obligations. With respect to any of our product candidates that may enter clinical development, we and our third-party contractors and CROs are required to comply with GCP requirements, which are regulations and guidelines enforced by the FDA and comparable foreign regulatory authorities. Regulatory authorities enforce these GCPs through periodic inspections of clinical trial sponsors, principal investigators, and clinical trial sites. If we or any of our CROs, or any principal investigators or clinical trial sites involved in our trials, fail to comply with applicable GCPs, the clinical data generated from these clinical trials may be deemed unreliable and the FDA or comparable foreign regulatory authorities may require us to perform additional clinical trials before approving our marketing applications. We cannot be certain that upon inspection by a given regulatory authority, such regulatory authority will determine that any of our clinical trials comply with GCP regulations. In addition, our clinical trials must be conducted with product produced under cGMP regulations. Our failure to comply with these regulations may require us to repeat clinical trials, which would delay the regulatory approval process for the relevant product candidate.

Further, principal investigators, clinical trial sites and CROs are not our employees, and we are unable to control, other than by contract, the amount of resources, including time, that they devote to our product candidates and clinical trials. If our CROs are unable to attract, retain, and motivate qualified personnel, they may be unable to perform their obligations in a timely manner, or their performance may be substandard. If principal investigators, clinical trial sites or CROs fail to devote sufficient resources to the development of our product candidates, or if their performance is substandard or does not meet our quality requirements, it may delay or compromise the prospects for approval and commercialization of any such product candidates. In addition, in order for these third parties to perform under their contracts with us, we regularly disclose or plan to disclose to these third parties confidential or proprietary information, which increases the risk that this information will be misappropriated. Additionally, disruptions caused by global geo-political, economic, and other factors beyond our control, including the ongoing COVID-19 pandemic, may increase the likelihood that these third parties encounter difficulties or delays in performing their obligations to us, including with respect to initiating, enrolling, conducting, or completing our planned clinical trials. In particular, we have experienced and may continue to experience difficulty in accessing animal models, specifically non-human primate models, for the preclinical evaluation of our product candidates. Delays caused by the inability to access these models may cause our development timelines to be extended beyond what we anticipate.

Third parties, including our CROs, generally have the right to terminate their agreements with us in the event of an uncured material breach by us. In addition, certain third parties may have the right to terminate their respective agreements with us under other circumstances, including if it can be reasonably demonstrated that the safety of the subjects participating in our clinical trials warrants such termination, if we make a general assignment for the benefit of our creditors, or if we are liquidated.

There is a limited number of third parties, including service providers and clinical trial sites, that specialize or have the expertise required to achieve our business objectives. If any of our relationships with these third-parties, including laboratories, CROs, or clinical trial sites, terminate, we may not be able to enter into arrangements with alternative third parties or to do so in a timely manner or on commercially reasonable terms. If these third parties do not successfully carry out their contractual duties or obligations or meet expected deadlines, if they need to be replaced, or if the quality or accuracy of the data they obtain is compromised due to the failure to adhere to our preclinical or clinical protocols, regulatory requirements, or for other reasons, our preclinical or clinical trials may be extended, delayed, or terminated and we may not be able to obtain regulatory approval for or successfully commercialize our product candidates. As a result, our results of operations and the commercial prospects for our product candidates would be harmed, our costs could increase, and our ability to generate revenues could be delayed. Switching from existing service providers or clinical trial sites, or adding additional service providers or clinical trial sites, involves additional cost and requires management time and focus. In addition, there is a natural transition period when a new service provider commences work. As a result, delays can occur, which may materially impact our ability to meet our desired development, including clinical development, timelines. Additionally, service providers may lack the capacity to absorb higher workloads or take on additional capacity to support our needs. Though we carefully manage our relationships with these service providers, including our contracted laboratories and CROs, there can be no assurance that we will not encounter these types of challenges or delays in the future or that these delays or challenges will not have a material adverse impact on our business, financial condition, and prospects.

In addition, clinical investigators may serve as scientific advisors or consultants to us from time to time and may receive cash or equity compensation in connection with such services. If these relationships and any related compensation result in perceived or actual conflicts of interest, or the FDA concludes that the financial relationship may have affected the conduct or interpretation of one of our preclinical studies or clinical trials, the integrity of the data generated from such preclinical study or clinical trial may be questioned and the utility of the preclinical study or clinical trial itself may be jeopardized, which could result in the delay or rejection by the FDA of any regulatory submissions related to our product candidates. Any such delay or rejection could prevent us from commercializing our product candidates.

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Risks Related to Intellectual Property and Information Technology

We may not be able to protect our intellectual property rights throughout the world.

Patent rights are national or regional rights. The filing, prosecution, maintenance, and defense of patent rights on our platform technologies and product candidates worldwide would be prohibitively expensive, and our intellectual property rights in some countries outside the United States may have a different scope and strength than do those in the United States. In addition, the laws of some foreign countries, particularly certain developing countries, do not protect intellectual property rights to the same extent as federal and state laws in the United States. Consequently, we may not be able to prevent third parties from practicing our intellectual property rights in all countries outside the United States or from making, using, selling, or importing products made using our intellectual property rights in and into the United States or other jurisdictions. Competitors may use our technologies in jurisdictions where we have not obtained intellectual property rights, including patent protection, to develop their own products and may also export otherwise infringing products to territories where we have intellectual property rights, including patent protection, but enforcement rights are not as strong as those in the United States. These products may compete with our products and our patent or other intellectual property rights may not be effective or adequate to prevent them from competing.

Many companies have encountered significant problems in protecting and defending intellectual property rights in foreign jurisdictions. The legal systems of certain countries, particularly certain developing countries, do not favor the enforcement of patents, trade secrets, and other intellectual property, particularly those relating to biopharmaceutical products, which could make it difficult in those jurisdictions for us to stop the infringement or misappropriation of our patents or other intellectual property rights, or the marketing of competing products in violation of our proprietary rights. Proceedings to enforce our patent and other intellectual property rights in foreign jurisdictions are expensive, especially in jurisdictions where we have no local presence, and could result in substantial costs and divert our efforts and attention from other aspects of our business. Furthermore, such proceedings could put our patents at risk of being invalidated, held unenforceable, or interpreted narrowly, could put our patent applications at risk of not issuing, and could provoke third parties to assert claims of infringement or misappropriation against us. We may not prevail in any lawsuits that we initiate, and the damages or other remedies awarded, if any, may not be commercially meaningful. Similarly, if our trade secrets are disclosed in a foreign jurisdiction, competitors worldwide could have access to our proprietary information, and we may be without satisfactory recourse. Such disclosure could have a material adverse effect on our business. Moreover, our ability to protect and enforce our intellectual property rights may be adversely affected by unforeseen changes in foreign intellectual property laws. In addition, certain developing countries, including China and India, have compulsory licensing laws under which a patent owner may be compelled to grant licenses to third parties. In those countries, we and our licensors may have limited remedies if patents are infringed or if we or our licensors are compelled to grant a license to a third-party, which could materially diminish the value of those patents. In addition, many countries limit the enforceability of patents against government agencies or government contractors. This could limit our potential revenue opportunities. Accordingly, our efforts to enforce our intellectual property rights around the world may be inadequate to obtain a significant commercial advantage from the intellectual property that we develop or license.

Because of the expense and uncertainty of litigation, we may conclude that, even if a third party is infringing our issued patents, or any patents that may be issued as a result of our pending or future patent applications, or other intellectual property rights, the risk-adjusted cost of bringing and enforcing such a claim or action, which typically lasts for years before it is concluded, may be too high or not in the best interest of our company or our stockholders, or it may be otherwise impractical or undesirable to enforce our intellectual property against some third parties. Our competitors or other third parties may be able to sustain the costs of complex patent litigation or proceedings more effectively than we can because of their greater financial resources and/or more mature and developed intellectual property portfolios. In such cases, we may decide that the monetary cost of such litigation and the diversion of the attention of our management and scientific personnel could outweigh any benefit we may receive as a result of the proceedings and that the more prudent course of action is to simply monitor the situation or initiate or seek some other non-litigious action or solution. In addition, the uncertainties associated with litigation could compromise our ability to raise the funds necessary to initiate or continue our future clinical trials, continue our internal research programs, in-license needed technology or other product candidates, or enter into development partnerships that would help us bring our product candidates to market.

We depend on intellectual property licensed from third parties, and our rights to develop and commercialize our product candidates are subject to, in part, the terms and conditions of the licenses granted to us by such third parties. If we breach our obligations under these agreements or if any of these agreements is terminated, we may be required to pay damages, lose our rights to such intellectual property and technology, or both, which would harm our business.

We depend on patents, know-how, and proprietary technology, both our own and those that we license from others to research, develop, and commercialize our product candidates. We are a party to a number of intellectual property license agreements and acquisition agreements pursuant to which we have acquired certain of our core intellectual property rights. Moreover, we rely upon licenses to certain intellectual property rights and proprietary technology from third parties that are important or necessary for the development of our technology and products, including technology related to our manufacturing processes and our product candidates. These licenses may not provide exclusive rights to use such intellectual property and technology in all relevant fields of use or in all territories in which we may wish to develop or commercialize our technology and products in the future. As a result, we may not be

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able to prevent competitors from developing and commercializing competitive products in such fields of use or territories. These licenses may also require us to grant back certain intellectual property rights to our licensors and to pay certain amounts relating to sublicensing patent and other rights.

In the future, we expect to enter into additional license agreements. For example, with respect to our ex vivo cell engineering platform relying on hypoimmune technology, we have licensed certain intellectual property from Harvard, UCSF, and Washington University. Additionally, we acquired our in vivo cell engineering platform, which is based on fusogen technology, from Cobalt, which included several license agreements and options-to-license, as well as our glial progenitor cell and cardiomyocyte programs from Oscine and Cytocardia, respectively, both of which came with in-licenses. These license and acquisition agreements impose, and we expect that future license and acquisition agreements will impose, various diligence, milestone, and royalty payment, and other obligations on us. If we fail to comply with our obligations under these agreements, we may be required to pay damages, and the licensor may have the right to terminate the agreement. Any termination of these licenses could result in the loss of significant rights and could harm our ability to develop or advance one of our cell engineering platforms, or develop, manufacture, or commercialize one of our product candidates. See the subsection titled “Business— Key Intellectual Property Agreements” in Part I, Item 1 of this Annual Report for additional information regarding these key agreements.

In addition, the agreements under which we license intellectual property or technology to or from third parties are complex, and certain provisions in such agreements may be susceptible to multiple interpretations. The resolution of any contract interpretation disagreement that may arise could narrow what we believe to be the scope of our rights to the relevant intellectual property or technology or increase what we believe to be our financial or other obligations under the relevant agreement, either of which could have a material adverse effect on our business, financial condition, results of operations, and prospects. Moreover, if disputes over intellectual property that we have licensed prevent or impair our ability to maintain our current licensing arrangements on commercially acceptable terms, we may be unable to successfully develop and commercialize the affected product candidates. Our business would also suffer if any current or future licensors fail to abide by the terms of the license, if such licensors fail to enforce licensed patents against infringing third parties, if the licensed patents or other rights are found to be invalid or unenforceable, or if we are unable to enter into necessary licenses on acceptable terms or at all. Moreover, our licensors may own or control intellectual property that has not been licensed to us and, as a result, we may be subject to claims, regardless of their merit, that we are infringing or otherwise violating the licensor’s rights.

In addition, while we cannot currently determine the amount of the royalty obligations we would be required to pay on sales of future products, if any, the amounts may be significant. The amount of our future royalty obligations will depend on the technology and intellectual property we use in product candidates that we successfully develop and commercialize, if any. Therefore, even if we successfully develop and commercialize any product candidates, we may be unable to achieve or maintain profitability.

If we are unable to successfully maintain the existing intellectual property rights we have, we may have to abandon development of the relevant research programs or product candidates, and our business, financial condition, results of operations and prospects could suffer.

Licensing of intellectual property is of critical importance to our business, involves complex legal, business, and scientific issues and is complicated by the rapid pace of scientific discovery in our industry. Disputes may also arise between us and our licensors regarding intellectual property subject to a license agreement, including those relating to: