Sana Biotechnology, Inc.

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 biologic drugs to clinical practice, enabling us to repair cells in the body when possible and replace them when needed. We are developingex vivo andin vivo cell engineering platforms to revolutionize treatment across a broad array of therapeutic areas with unmet treatment needs, including type 1 diabetes, B cell mediated autoimmune diseases, and oncology.

For ourex vivo platform, we have made focused investments in our hypoimmune platform technology, which we refer to as our HIP technology, with the twin goals of engineering allogeneic cells that can "hide" from the patient's immune system to overcome the fundamental challenge of immune rejection and cell persistence, and that we can manufacture at scale. A successful therapeutic requires cells that can engraft, function, and persist in the body, and we believe our approach can unlock a wave of disruptive therapeutics. Forin vivo therapies that aim to repair and control genes in the body, a successful product candidate requires both gene modification andin vivo delivery of the therapeutic payload. Of these, we view effectivein vivo delivery as the greatest current limitation to dramatically expanding the impact of this class of therapeutics. To this end, our initial focus is on cell-specific delivery of genetic payloads that integrate into the genome of the target cells.

We currently focus our efforts across three areas and have three ongoing clinical trials across multiple disease types and therapeutic areas, including type 1 diabetes (T1D), B cell mediated autoimmune diseases, and B cell malignancies.

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Type 1 Diabetes: Approximately nine million people suffer from type 1 diabetes (T1D) worldwide, and there have been no major novel medicines for the disease since insulin. We are developing SC451, a HIP-modified, stem cell derived pancreatic islet cell therapy, for the treatment of T1D. The goal of this therapy is euglycemia, or normal blood glucose, without the need for exogenous insulin injections or immunosuppression. We currently have an ongoing investigator-sponsored first-in-human study (IST) evaluating UP421, an allogeneic, primary islet cell therapy engineered with our HIP technology, in patients with T1D. Sana expects to share additional data in 2025 and file an investigational new drug application (IND) for SC451 as early as 2026.

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Allogeneic CAR T cells: We are developing SC291, our HIP-modified allogeneic CD19-dirtected allogeneic CAR T cell product candidate, in patients with B cell mediated autoimmune diseases. The GLEAM study is a Phase 1 clinical trial evaluating SC291 in patients with lupus nephritis (LN), extrarenal lupus (ERL), and antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis. If successful, SC291 has the potential to benefit patients in a number of additional B cell-mediated autoimmune diseases. We are also studying SC262, our HIP-modified allogeneic CD22-directed CAR T cell product candidate. The VIVID study is a Phase 1 clinical trial evaluating SC262 in patients with relapsed and/or refractory (R/R) B cell malignancies who have received prior CD19-directed CAR T therapy. Sana is enrolling patients in both the GLEAM and VIVID trials and expects to share data from each study in 2025.

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In vivo CAR T cells: We are developing SG299, a CD8-targeted fusosome that leverages our fusogen platform technology. This platform enables cell-specific, in vivo delivery of various payloads, allowing SG299 to deliver genetic material to CD8+ T cells that directs them to become CD19-targeting CAR T cells, while avoiding delivery to potentially problematic tissues such as the liver and gonads. Sana plans to develop SG299 in a range of B cell cancers and B cell mediated autoimmune diseases and expects to file an IND for SG299 as early as 2026.

In December 2024, UP421, a HIP-modified allogeneic primary islet cell product, was transplanted into a patient with T1D in the IST, which is being conducted at Uppsala University Hospital. This Phase 1 study evaluates the safety of UP421 when transplanted intramuscularly into a patient with T1D. Secondary endpoints include immune evasion measured in peripheral blood, non-fasting C-peptide concentrations (which is a measure of the body’s insulin production) in peripheral blood, C-peptide response to a mixed meal tolerance test (MMTT), and graft survival assessed by magnetic resonance imaging (MRI). The transplantation was performed without immunosuppression, steroids, or any supportive medication to facilitate allogeneic cell survival. As a first-in-human study, the primary endpoint was safety and the dose was approximately 2% to 7% of islet cells that would typically be needed for insulin independence. In January 2025, we announced positive results from the IST at four weeks after cell transplantation, which demonstrated the survival and function of pancreatic beta cells as measured by the presence of circulating C-peptide, a biomarker indicating that transplanted beta cells are producing insulin.

Positive preliminary twelve-week clinical results, building on the four-week results, demonstrate that all primary and secondary endpoints were met. The 42-year-old recipient, who had been living with T1D for over 30 years, received a single transplant of UP421 into the muscle of the forearm. The primary endpoint of safety was achieved with no drug product-related adverse events reported. Prior to transplant, C-peptide levels were undetectable both in the non-fasting state and in response to an MMTT. Pancreatic beta cells produce pro-insulin, which is cleaved and secreted as insulin and C-peptide in a 1:1 ratio, making C-peptide a well-established biomarker of endogenous insulin production. Results of the study at four- and twelve-weeks after cell transplantation demonstrate the survival and function of pancreatic beta cells as measured by the presence of circulating C-peptide. C-peptide levels also increase with an MMTT during testing at these timepoints, consistent with insulin secretion in response to a meal. MRI scanning also demonstrated a sustained signal at the site of transplanted cells over time, which is consistent with graft survival. No inflammation or safety-related signals were observed.

The UP421 drug product contains a mixture of islet cell populations: wild-type (WT) islet cells expressing HLA class I and class II, double knockout (DKO) islet cells with HLA class I and class II eliminated, and HIP islet cells with both HLA class I and class II eliminated plus CD47 overexpression. WT islet cells triggered a robust immune response, with peak T cell activation at day 7 following transplantation, followed by T cell-mediated killing, and development of donor-specific antibodies. DKO islet cells, while avoiding T cell activation and antibody responses, were rapidly eliminated by natural killer (NK) cells. In contrast, HIP islet cells demonstrated comprehensive immune evasion, with no evidence of T cell activation, donor-specific antibody development, or NK cell-mediated killing through twelve weeks. These distinct immune responses were further validated in whole blood assays, in which HIP islet cells uniquely survived exposure to the patient's PBMCs while both WT and DKO islet cells were eliminated.

To our knowledge, this study is the first example of successful transplantation with no immunosuppression into a person with an intact immune system to demonstrate survival and function of allogeneic cells. We believe these initial results with HIP-modified cells represent a significant milestone for the field of cell therapy. The results are a key landmark in our effort to develop SC451, our HIP modified stem cell-derived pancreatic islet cell product candidate, as an off-the-shelf cell therapy for patients with T1D. The 12-week data remain subject to source data verification, after which we and our collaborators at Uppsala University Hospital expect to publish in scientific journals and/or present at scientific conferences more details and longer follow-up from this study in 2025 and beyond. We expect to submit an IND for SC451 as early as 2026.

GLEAM is a Phase 1 clinical trial evaluating SC291 in patients with LN, ERL, and ANCA-associated vasculitis. Clinical studies conducted by third parties evaluating B cell depleting agents in B cell mediated autoimmune disease have established that deep B cell depletion is an important correlate of clinical activity, with deeper B cell depletion correlating with better clinical activity for the agents.

We have also studied SC291 in patients with B cell malignancies in a trial we refer to as ARDENT, in which we have seen a tolerable safety profile. Among sixteen patients, we observed no cases of Grade 2 or higher cytokine release syndrome (CRS), of any Grade immune effector cell-associated neurotoxicity syndrome (ICANS), or of graft versus host disease (GvHD). We observed a single case of Grade 1 immune effector cell associated hemophagocytic lymphohistiocytosis-like syndrome (IEC-HS). All six evaluable non-Hodgkin's lymphoma (NHL) patients treated at the two highest cell dose cohorts showed deep B cell depletion. We are optimistic that if we observe safe and deep B cell depletion in the GLEAM study similar to that observed in these cohorts of the ARDENT study, then SC291 could have a meaningful clinical benefit for patients in the autoimmune indications being evaluated in GLEAM. In December 2024, the U.S. Food and Drug Administration (FDA) granted Fast Track designation for SC291 in relapsed/refractory systemic lupus erythematosus (SLE), which includes LN and ERL. Fast Track designation is designed to facilitate development and expedite review of drugs that address serious conditions and unmet medical needs.

With respect to ourin vivo cell engineering research efforts, in January 2025, we shared data from preclinical studies involving our SG299 CAR T cell fusosome product candidate, a CD8-targeted fusosome that delivers a CD19 CAR to target CD19+ cells. In a non-human primate (NHP) study exploring the potential efficacy of this therapy, intravenous (IV) injection of a surrogate SG299 together with an additional component resulted in the generation of CAR T cells that induced deep B cell depletion in the peripheral blood and lymph nodes at 28 days. We believe that deep B cell depletion is an important biomarker for potential efficacy in patients with B cell mediated autoimmune diseases and B cell mediated cancers. Separately, in a good laboratory practice (GLP) toxicology study in NHPs, we observed that a single IV injection of SG299 demonstrated selective, dose-dependent gene delivery to CD8+ T cells. Tissue analysis showed minimal to no quantifiable presence in non-target tissues, including the liver and gonadal tissue. For additional information, see the section titled “T Cell Fusosome Approach” below.

In November 2024, we announced a portfolio prioritization in which we suspended development of SC291 in oncology in the ARDENT study and SC379, our stem-cell derived glial progenitor cell product candidate, in various central nervous system diseases.

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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Experienced Company Builders. We have numerous individuals with vast experience in building disruptive biotech companies, having expertise in basic research, clinical medicine, finance, company building, and operations.

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Leading Scientists and Drug Developers. We believe that in order to successfully develop engineered cells as medicines, significant investments in infrastructure and cross-functional capabilities need to be coupled with deep scientific and development expertise in the cell types and diseases of interest within each program. We have assembled a team with deep expertise in transplant immunology, T cell biology, stem cell biology, type 1 diabetes, basic immunology, autoimmunity, drug discovery, and drug development.

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Experienced Manufacturing Scientists, Engineers, and Operators. We have assembled manufacturing sciences and operations expertise on our board, on our executive team, and across the company.

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Board and Investors with Shared Long-Term Vision. Our board of directors is composed of renowned company builders, scientists, drug developers, and investors who share our long-term vision of advancing engineered cells as medicines to change the lives of patients. Our board of directors is a resource that has enabled our strategy of consolidating technologies, assets, and people to expand the potential impact of our long-term vision.

Our capabilities enable us to take a comprehensive approach to the most important and difficult aspects of engineering cells. We are pursuing bothex vivo andin vivo cell engineering platforms 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 each of our potentially transformative therapies. We have built significant internal capabilities across a wide range of areas focused on solving the most critical limitations in engineering cells including:

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Stem Cell and Disease Biology. Developing our platforms into therapies for patients requires a deep understanding of both cell and disease biology. Furthermore, we are investing significantly in our people and the technologies that enable the differentiation of pluripotent stem cells (PSC) into mature cells that can be used as therapeutics.

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Immunology. The immune system can be harnessed to treat multiple diseases, and it can also limit the therapeutic effect of many cell- and gene-based therapies. Understanding and harnessing the immune system can have a broad impact across ourex vivo andin vivo cell engineering portfolio. Our hypoimmune technology, led by a team of transplant immunologists, has the potential to “hide” cells from the immune system, unlocking the potential of allogeneicex vivo cell therapies for the treatment of numerous diseases We are also investing in our people and technologies to harness the immune system, particularly T cells, for the treatment autoimmune diseases and cancer. .

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Genome Modification. The ability to knock-out, knock-in, modify, disrupt, and control expression of genes is fundamental to the success of our platforms. We believe our capabilities across multiple modalities will allow us to use the appropriate system for the biologic problem of interest.

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Gene Delivery. We believe our delivery technologies have broad potential, with both near-term and long-term applications across a number of indications. We are investing in technologies that allow payload delivery to specific cell types and increase the diversity of payloads.

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. A critical inflection point occurred when key technological advancements eventually enabled the broad development of protein drugs, including 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 cellsex 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 forex vivo cell engineering is to replace or add cells in the body such that those cells engraft, function, and persist over time, and to manufacture those cells cost-effectively at scale. Ourex vivo cell engineering platform uses our hypoimmune technology to create cells that can “hide” from the patient’s immune system to enable persistence of allogeneic cells. We are focused on making therapies using PSCs with our hypoimmune genetic modifications as the starting material, which we then differentiate into a specific cell type, such as a pancreatic islet cell, before treating the patient. Additionally, there are cell types for which effective differentiation protocols from a stem cell have not yet been developed, such as T cells. For such cell types, instead of starting from a PSC, we can use a fully differentiated allogeneic cell, 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 ourex vivo cell engineering technologies to make cell products for the treatment of multiple diseases.

In vivo Cell Engineering

Engineering cellsin vivo requires the development of both an appropriate delivery vector as well as a payload to effectively modify the target cell. Our goal forin 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. We believe that progress in any of these categories can allow us to make important medicines. Ourin vivo cell engineering platform harnesses fusogen technology, which targets cell surface receptors, enabling cell-specific delivery for a meaningful number of different cell types. We have shown in preclinical studies that our fusogen technology 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 ourex vivo andin vivo engineering pipeline, we have used the following strategies:

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minimize biology risk where there is platform risk, or in other words, prioritize opportunities where success with our platform should lead to success in addressing the underlying disease;

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prioritize program investments in diseases where the strengths of ourex vivo andin vivo cell engineering platforms can address the key limitations of existing therapeutic approaches;

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focus on conditions of high unmet need, including the most grievous diseases; and

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prioritize efforts where success in one area begets success in others.

Our Pipeline

We are developing a broad pipeline of clinical product candidates focused on creating transformativeex vivo andin vivo therapies across a range of therapeutic areas. We are in the early stages of development across a broad pipeline of product candidates, which are summarized below:

1 Investigator sponsored trial. Abbreviations: AAV, ANCA-associated vasculitis; NHL, non-Hodgkin’s lymphoma; SLE, systemic lupus erythematosus; T1D, type 1 diabetes; WW, worldwide.

Each of our programs provides the potential for meaningful standalone value while also supporting our potential ability to further exploit our platforms in a manner that leads to the development of broadly applicable medicines.

PSC-derived Pancreatic Islet Cells

SC451

SC451 is our PSC-derived hypoimmune pancreatic islet cell product candidate for the treatment of diabetes, with an initial focus on T1D. More than nine million patients worldwide have T1D, 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. These patients represent a small fraction of the overall global diabetes population, which is estimated to be approximately 540 million. T1D patients typically need to take multiple insulin injections every day for life. Although the introduction of insulin has had a profoundly positive impact on patients and there has been significant improvement in convenience for patients over the past several decades with the introduction of insulin pumps and continuous glucose monitors, people with T1D 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 have shown that we can develop high quality stem cell-derived islet cells that, when transplanted in animal models, normalize blood glucose and cure diabetes. We have also shown that our hypoimmune cells induce no systemic immune response, survive, and function in a patient with T1D. We are combining these capabilities and learnings into SC451, and we plan to submit an IND as early as 2026.

These human data are supported by preclinical data in several models, including in NHPs with a pre-existing immune response to non-hypoimmune cells and in a diabetic NHP, where allogeneic, HIP-modified NHP pancreatic islet cells survive and function for the duration of our NHP studies, the longest of which is about forty weeks. To demonstrate applicability in the context of the autoimmunity seen in people with T1D, we have developed a proprietary mouse model in-house with human immune cells from a T1D patient. In this model, we showed that HIP modifications enabled stem cell-derived pancreatic islet cells derived from a patient with T1D to evade both the autoimmune and allogeneic immune response, survive, and function for the duration of the study.

T1D is a disease of missing pancreatic beta cells. Previous results from others have shown that either primary or PSC-derived pancreatic islets, which given with significant immunosuppression, can allow patients to control blood glucose without the need for insulin therapy. Our human clinical data and our preclinical HIP data support that our HIP-modified pancreatic islets can evade immune detection and potentially eliminate immunosuppression for patients treated with HIP-modified, PSC-derived pancreatic islets. We believe our HIP-modified, PSC-derived pancreatic islets have the potential to create a disruptive treatment for T1D, offering patients life-long normal blood glucose without immunosuppression.

HIP Primary Islet Cells

UP421

UP421 is a HIP-modified allogeneic primary islet cell product that was first transplanted, with no concomitant immunosuppression, into a patient with T1D in December 2024 in an IST being conducted at Uppsala University Hospital. This Phase 1 trial has a primary endpoint of safety and also evaluates secondary endpoints, including survival and function of the islet cells. The safety data, secondary endpoints, dosing rationale, clinical outcomes, and immune analysis from the first treated patient are summarized above under the section titled “Overview.” The study is ongoing and continues to evaluate safety, persistence, and function of the transplanted cells.

Allogeneic T Cell Platform

We are applying our hypoimmune technology to donor-derived T cells to develop allogeneic cell therapies for B cell mediated autoimmune diseases and B cell malignancies. These programs are designed to address a major limitation of existing allogeneic CAR T cell therapies: the need to evade host versus graft responses (HvGR) that occur when a patient’s immune system kills the transplanted T cells, limiting the potential benefit of the therapy. The rapid killing of the transplanted cells may be a major contributor to the short-lived responses seen in patients treated with allogeneic CAR T cells. 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 suppressed immune system inevitably recovers and eliminates the CAR T cells, limiting the effectiveness of the therapy. Our hypoimmune technology is designed to enable cells to “hide” from the patient’s immune system, giving our allogeneic CAR T cell platform the potential to create medicines that persist longer in patients and avoid the risks associated with higher doses of chemotherapy.

SC291

SC291 is being evaluated in patients with LN, ERL, and ANCA-associated vasculitis in a Phase 1 dose escalation study that we refer to as our GLEAM trial. Patients are currently being enrolled and dosed in this study and we expect to share data in 2025. B cell depleting therapies, such as anti-CD20 antibodies (e.g., rituximab), have shown clinical benefit in the treatment of multiple autoimmune disorders that involve production of autoimmune antibodies, including LN, ERL, ANCA-associated vasculitis, and many others. The rituximab trials in SLE afforded the key insight that the depth of B cell depletion was associated with improved patient responses. Although these antibodies are adept at depleting B cells in circulation for many patients, they are unable to penetrate deeply into the germinal centers of the lymph node and tissues, where the pathogenic B cells continue to survive and drive disease. CD19-directed CAR T cells are known to cause deep B cell depletion in CAR T therapy recipients. Georg Schett and his research group in Erlangen, Germany tested the treatment of refractory SLE patients with autologous CD19-directed CAR T cells and were successful in inducing long-lasting drug-free remissions for these patients. In our ARDENT trial, we observed the pharmacodynamic effect of peripheral blood B cell depletion, which refers to diminishing B cell counts in the peripheral blood, associated with SC291 treatment in patients. Although pharmacodynamic effects seen in oncology patients may not translate to patients with autoimmune disease, we believe these data increase the probability that SC291 treatment will confer similar B cell depletion, the putative mechanism of benefit, to patients with B cell mediated autoimmune diseases.

SC291 also provides the benefit of being available “off the shelf,” avoiding the complex management of patients with respect to the apheresis procedure for cell harvest and between cell harvest and infusion required for treatment with autologous CAR T products, while also providing the potential for increased manufacturing scalability.

SC262

We are developing SC262, our hypoimmune-modified CD22-directed allogeneic CAR T program, initially as a potential treatment for patients with relapsed and/or refractory B cell malignancies who have received prior CD19-directed CAR T therapy in NHL. In January 2024, the FDA cleared our IND to evaluate SC262 in this patient population in a Phase 1 clinical study that we refer to as our VIVID trial. We are enrolling patients in this trial and expect to share data in 2025. The CD22-directed CAR construct that we use in SC262, which we licensed from the National Institutes of Health, has already been evaluated in multiple academic clinical trials of autologous CAR T cell therapies, data from which have shown complete responses (CR) in a substantial number of patients that have relapsed following treatment with a CD19-directed CAR T therapy. For example, data from a Phase 1 trial (n=38) of NHL patients conducted at Stanford University, where 97% of patients were either refractory and/or relapsed after prior CD19-directed CAR T therapy, demonstrated a CR rate of 53% and an overall response rate (ORR) of 68%. Seventy-five percent of the CRs lasted 12 months or longer.

Our allogeneic T cell platform is designed to enable the substitution of CAR constructs in a modular fashion. For the near-term, we are prioritizing clinically validated targets as well as CAR constructs, such as our CD19-targeted CAR, that have shown promising safety and efficacy profiles in the autologous context. In the future, additional candidates may be nominated to address various diseases, such as autoimmune diseases, hematological malignancies, and solid tumors.

In vivo CD19-Directed CAR T Cells

SG299

Our most advanced CAR T cell fusosome product candidate is SG299, a CD8-targeted fusosome that delivers a CD19-directed CAR to target CD19+ cells. We are developing SG299 to treat patients with hematologic malignancies and B cell mediated autoimmune diseases. Ourin vivo platform provides an opportunity to develop potential product candidates that can expand access to CAR T cell therapy to patients in need. The effectiveness ofex vivo-manufactured CAR T cells currently depends on the administration of a lymphodepleting preparative regimen prior to infusion to facilitate expansion of the CAR T cell product, which can have an adverse impact on safety. We do not expect to need a lymphodepleting regimen prior toin vivo delivery of the CAR gene via fusosome, as our goal is to expose our fusosomes to as many T cells in the body as possible. We also believe the ability to deliver a payload encoding a CAR to a T cell without significantex vivo manipulation has the potential to be more effective thanex vivo-manufactured CAR T cell products, generating therapeutically active CAR T cells without the complexities and delays associated with the processes of T cell collection andex vivo manufacturing that are used in currently approved autologous CAR T cell products. Furthermore, theex vivo expansion of cells in the presence of high cytokine concentrations, although necessary for the manufacture of currently 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 environmentin vivohas the potential to improve the quality of the CAR T cell generated, potentially improving both efficacy and the side effect profile We anticipate submitting an IND for SG299 as early as 2026.

Ourex vivo Cell Engineering Platform

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

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engraftment of the right cell in the right environment;

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appropriate function of the cells, necessitating an understanding of and ability to produce the desired cell phenotype;

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persistence of the cells in the host, particularly by overcoming immune rejection; and

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manufacturing the desired cell in the quantities required.

Ourex 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 cells are derived from 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 ourex vivo cell engineering platform by investing in solutions to address the key challenges outlined above:

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Stem cell and disease biology. We believe that it is critical to have expertise in the developmental biology of stem cell differentiation and a deep understanding of the desired cell biology of stem cell differentiation in order to generate cells that function appropriately, as well as a deep understanding of the desired cell phenotype. The latter requires expertise in normal and disease biology. Furthermore, clinical understanding of disease pathology and transplant medicine is required to determine how to engraft the right cell in the right environment. Each of our programs is led by a prominent clinician-scientist with deep expertise in both cell therapy and disease biology.

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Immunology and genome modification. We believe that a deep understanding of the immunological response to allogeneic cells is essential to unlocking the potential ofex vivo cell therapies. We have invested significantly in transplant immunology to understand the drivers of this immune response and potential cell modifications that will hide cells from allogeneic rejection. We have also built gene editing, genome modification, and gene insertion capabilities in order to modify the genome of cells so that transplanted, allogeneic cells can evade immune detection.

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Manufacturing. We are investing proactively in process development, including process optimization and scale up, analytical development, CMC regulatory, supply chain, quality, and other manufacturing sciences in order to develop processes that can enable scalable manufacturing of cell therapies and broad patient access. We have entered into agreements with contract development and manufacturing organizations (CDMOs) and other partners for access to facilities and reagents in our supply chain necessary to manufacture our product candidates. We have built a pilot manufacturing plant in South San Francisco, California and entered into a long-term lease agreement for a manufacturing facility in Bothell, Washington. We are also investing to obtain and ensure access to high quality donor-derived T cells and current good manufacturing practice (GMP)-grade PSC lines for our programs. We will continue to invest in our manufacturing capabilities to ensure our pipeline needs are met.

We have prioritized cell types for our programs when:

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high unmet need can be addressed by cell replacement;

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existing proof of concept in humans and/or animal models demonstrates that cell transplantation should have a clinical benefit;

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evidence exists that the cell type can be successfully differentiated from PSCs and that such PSC-derived cells can function appropriatelyin vivo;

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there has been the ability to hire or partner with world experts in the field to ensure our programs are rooted in a deep understanding of the underlying cell and disease biology; and

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evading immune system rejection via the hypoimmune technology is either not required initially or is the critical missing element to developing a cell therapy (such as pancreatic islet cells).

Based on this prioritization, we are currently focused on two cell types: pancreatic islet cells and T cells.

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, complex surgical procedures, and immune rejection of the donated organs have limited the impact of these procedures.

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 HvGR, coupled with novel techniques to manipulate the immunological profile of cells via gene editing, have raised the prospect thatex vivo engineered cells can 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), induced pluripotent stem cells (iPSCs), and donor-derived cells. Our portfolio currently includes a mix of sources.

Crucial aspects of developing allogeneic cells from any source include a 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 GMP, 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 intended to yield sources of cells suitable for the global clinical development and commercialization ofex vivo engineered cells for a broad patient population, in line with our vision to democratize access.

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 PSCs that have the potential to differentiate into any cell type and are derived from the inner cell mass of a blastocyst or pre-implantation stage embryo. They are typically culturedin 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 being free of potentially deleterious genetic mutations. Because PSCs 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 inex vivo engineered cells. A key breakthrough in 2006 demonstrated 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 use in our T cell programs, comes from mature donor-derived allogeneic cells. Although these T cells are neither pluripotent nor from an infinitely renewable source, they can be obtained as mature cells from human donors at scale. The use of donor-derived cells for our T cell platform may enable us to more rapidly advance product candidates towards the clinic with the implementation of our hypoimmune technology.

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, transplant rejection 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.

Further studies established that T cells play 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 from degraded intracellular proteins on the cell surface. 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 immunogenicity 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. Although this approach 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, 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 it 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 used to date to overcome immune rejection, with limited success:

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Immune Suppression. Cyclosporine and other molecules that suppress T cell responses are commonly used, and many patients have been helped by these approaches in areas such as an organ transplantation. However, immune suppression often leads to significant systemic side effects, including a decreased ability to resist infections, increased susceptibility to cancer, and a wide variety of organ toxicities. Furthermore, organ transplant recipients typically require immunosuppression on a lifelong basis, and any disruption in this immunosuppression can rapidly trigger transplant rejection.

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Matching HLA Type. A second approach to overcoming immune rejection is to find a donor with a matched human leukocyte antigen (HLA) type. In humans, HLA is a synonym for MHC. This approach addresses the root of the mechanism that the immune system uses to identify “non-self” cells and has achieved some success. Finding a matched donor, however, can be difficult and is usually limited to close relatives who are willing and able to donate. Although some have advocated for creating large banks of cells that match a wide variety of HLA types, even with fully matched HLA class I and class II donors and recipients, there is a need for at least some immune suppression due to the presence of numerous minor antigen mismatches.

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Autologous Approaches. More recently, researchers have pursued autologous approaches, where a patient’s own cells are modified and introduced back into the patient as a graft. These cells may avoid immune rejection as they would be recognized as “self.” Autologous approaches have demonstrated effectiveness in certain diseases, such as autologous CAR T cells for hematological malignancies, but these approaches are limited in their adoption due to manufacturing cost and complexity. Furthermore, autologous approaches are generally limited to cells that exist in the patient in suspension, such as blood cells.

Our Solution – Hypoimmune Technology

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

Some of our scientific founders and their collaborators have worked on creating hypoimmune cells for well over a decade. A key insight that informed their work is 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 bothin vitro andin vivoin animal models.

Designing Hypoimmune Cells

Our goal is to create a universal cell capable of evading immune detection, regardless of cell type or transplant location. Our current clinical hypoimmune technology, which is being used in our SC291 and SC262 product candidates, combines three genome modifications to “hide” these cells from the host immune system:

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disruption of MHC class I expression;

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disruption of MHC class II expression; and

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overexpression of CD47, a protein that enables cells to evade the innate immune system, including macrophages and NK cells.

Once these modifications have been applied to a cell, we refer to that cell as a hypoimmune cell.

Creating Hypoimmune Therapeutic Cells from Human iPSCs

Our current clinical 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 NK) cells. PSCs from healthy donors are used as the starting material and are then genetically modified with the hypoimmune modifications. These edited cells are then differentiated into cell types of therapeutic interest, which could potentially be administered to a patient as an “off the shelf” therapy.

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, (iv) transplanting NHP hypoimmune iPSCs into MHC mismatched allogeneic NHPs, (v) transplanting NHP hypoimmune iPSC-derived differentiated cells, such as cardiomyocytes or retinal pigment epithelial cells (RPEs), into MHC mismatched allogeneic NHPs, and (vi) transplanting NHP hypoimmune primary cells, such as islets, into MHC mismatched diabetic and non-diabetic NHPs.

We have shown that HIP-modified cells survive and evade immune detection in each of these settings. Importantly, these results include experiments in NHPs, including testing of hypoimmune primary islets. We have shown that hypoimmune primary islets can mediate insulin independence in a fully immunocompetent diabetic NHP without immunosuppression. These results confirm that hypoimmune modifications confer immune evasion without compromising islet function in this setting. We are encouraged by the data from these investigations, given the similarity of the NHP immune system to the human immune system and that NHP models represent the strictest test outside of evaluating these cells in humans.

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 unmodified mouse iPSCs into MHC mismatched allogeneic mice, and as expected, these unmodified mouse iPSCs were rapidly rejected by the recipient mouse 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 disrupted. These modifications protected the cells from the recipient mouse’s adaptive immune system, but NK cells rapidly killed the transplanted cells. These data highlight the importance of all three genome modifications (MHC class I, MHC class II, and CD47 overexpression) in protecting cells from the immune system following an allogeneic transplant.

Next, to ensure that hypoimmune genome 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, the scientists tested whether the hypoimmune iPSCs cells could be differentiated into three different cell types, functionin vivo, and evade the host immune system. The three cell types were cardiomyocytes, endothelial cells, and smooth muscle cells. The hypoimmune iPSCs successfully differentiated 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 activation despite having received no immune suppression. Differentiated cells derived from unmodified iPSC cells led to immune activation in the host mice, which 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 transplantation.

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 by using a “humanized” mouse system, generated by grafting a functioning human immune system in place of the mouse immune system. We also evaluated the ability to successfully engineer human hypoimmune cells from human iPSCs and whether differentiated cells derived from human hypoimmune cells retain biological function.

First, the three genome modifications described above were replicated in human iPSCs to engineer a human hypoimmune cell line with properties comparable to the mouse hypoimmune cellsin vitro. Next, unmodified human iPSCs were transplanted into MHC mismatched humanized mice. It was observed that these unmodified 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 data we concluded that in humanized mice, human 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, which exhibited the characteristics of normal endothelial cells and cardiomyocytes. Finally, to test whether the differentiated cell types derived from human hypoimmune cells could 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 unmodified 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.

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 unmodified NHP iPSCs in one leg and a second injection of NHP hypoimmune cells at six weeks in the other leg (i.e., a crossover design). The second cohort received an initial injection of NHP hypoimmune cells in one leg, which allowed assessment of immune evasion in a naïve recipient. In order to model certain aspects of autoimmune disease, this cohort also received a second injection of unmodified NHP iPSCs in the other leg, which enabled assessment of the impact of injecting hypoimmune cells into an NHP with a pre-existing immune response to unmodified cells. No immunosuppression was administered to any of the NHPs in the study.

Allogeneic Hypoimmune iPSCs Survivein vivo in NHPs with Intact Immune Systems

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. At 6 weeks following the initial injection, NHPs were injected with the crossover cell type (Group 1 with hypoimmune NHP iPSCs and Group 2 with wt unmodified iPSCs). In these crossover experiments, hypoimmune NHP iPSCs survived even when the NHP had been exposed to unmodified iPSCs. Unmodified iPSCs 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 shown from single NHP belonging to each group; images are representative for four NHPs receiving hypoimmune iPSCs and four NHPs receiving wt iPSCs.

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

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 NHPs 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 iPSCs were susceptible to killing by NK cells, indicating protection from the “missing self” signal. Data above are collected from four NHPs in each experimental arm.

NHP hypoimmune iPSCs 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 in the four allogeneic recipients for the duration of the study, which was 16 weeks for two of the NHPs and 8 weeks for the other two NHPs. To our knowledge, this is the first instance of prolonged graft survival in an allogeneic transplant setting without immunosuppression in NHPs. By contrast, systemic immune responses from T cells as well as IgM and IgG antibodies were generated to iPSCs without the hypoimmune edits, and the iPSCs were rapidly rejected within two to three weeks.

In the crossover portion of this experiment, injection of NHP hypoimmune iPSCs into NHPs that had previously received unmodified iPSCs 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 iPSCs survived for the full eight weeks that they were monitored, suggesting that pre-existing immunity to unmodified human iPSCs had no impact on hypoimmune iPSC survival. By contrast, in the NHPs that had previously been injected with hypoimmune iPSCs, the unmodified NHP iPSCs elicited both T cell and antibody responses. Notably, these unmodified iPSCs were rapidly rejected by the NHP within one to two weeks, while the previously injected hypoimmune iPSCs continued to be viable in the other leg of the NHP. These results confirm 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 iPSCs have the potential for immune evasion even the context of a new immune response toward iPSCs without these edits.

In other experiments, we observed immune evasion and cell survival of hypoimmune NHP iPSC-derived cardiomyocytes and RPEs. In separate experiments, these cardiomyocytes and RPEs were injected into the hearts and eyes (subretinal space), respectively, of healthy allogeneic NHP recipients without immunosuppression. Both the hypoimmune cardiomyocytes and RPEs were found to evade systemic adaptive and innate immune responses and survived for the duration of the applicable experiment. Separately, we have shown that hypoimmune NHP islet cells transplanted into a non-matched allogeneic NHP survive for the duration of the 40-week study,

We conducted an experiment to better understand whether hypoimmune modifications impair the function of islet cells and to confirm that these modifications enable the islet cells to evade immune responses. For these experiments, we made hypoimmune genetic modifications to NHP primary islets and then transplanted these islets intramuscularly, without immunosuppression, into a different NHP. We found that the hypoimmune islets were viable for the full duration of the study (approximately 10 months) and did not elicit either an adaptive or innate immune response. By contrast, unmodified NHP primary islets injected into a separate NHP were rejected within one week. These results suggest that hypoimmune modifications enable allogeneic immune evasion by NHP primary islet cells and increase our confidence in the clinical translatability of this approach.

Primary Allogeneic Hypoimmune NHP Pancreatic Islet Cells Survive in NHPs for 10 Months Without Immunosuppression

Hypoimmune NHP primary islets (top row) or unmodified wild type (wt) NHP primary islets (bottom row) were introduced via intramuscular injection into allogeneic NHPs. Unmodified NHP primary islets are undetectable in recipient NHPs by week 1 while hypoimmune NHP primary islets introduced into naïve NHPs were viable and detectable until the experiment was terminated at 40 weeks following injection. Primary islet cell survival in vivo is followed over time using bioluminescence imaging (BLI).

In January 2024, we presented data from a study transplanting allogeneic HIP-modified pancreatic islet cells into a fully immunocompetent, diabetic NHP. Subsequent to diabetes being induced in the NHP with streptozotocin (STZ), daily insulin injections were performed to re-establish glucose control. After 78 days, the NHP underwent transplantation of HIP primary islets by intramuscular injection, resulting in insulin independence without the use of any immunosuppression. As early as one week after the transplantation, the NHP’s serum c-peptide level had normalized, and it remained stable throughout the follow-up period of six months. The NHP showed tightly controlled blood glucose levels for six months, was completely insulin-independent, and was continuously healthy throughout this period with no use of any immunosuppression. Up to six months following HIP primary islet transplantation, peripheral blood mononuclear cells and serum were obtained from the NHP for immune analyses. HIP primary islets showed no T cell recognition, no graft-specific antibodies, and were protected from NK cell and macrophage killing. To demonstrate that the NHP’s insulin-independence was fully dependent on the HIP primary islets and that there was no regeneration of the animal’s endogenous islet cell population, we triggered the destruction of the HIP primary islets using a CD47-targeting antibody. This resulted in a loss of glycemic control and return to exogenous insulin dependence. We believe these data demonstrate potential evidence for immune evasion of HIP primary islets, graft-mediated insulin-independence of the diabetic NHP, and a potential safety strategy.

Hypoimmune Islet Cells Achieve Insulin Independence after Allogeneic Transplantation in a Fully Immunocompetent NHP

Fasting glucose monitoring in an NHP for about 10 months encompassing pre STZ, post STZ, post HIP islet cell transplant, and post anti-CD47 phases of the study: Diabetes mellitus was induced in a male NHP with STZ and daily insulin injections were started. Blood glucose was monitored twice daily and showed major instability over approximately two weeks until a well-controlled steady state was reached. After 78 days, the NHP was underwent intramuscular transplantation with allogeneic HIP islet cells. Insulin support was gradually withdrawn over approximately 12 days. The NHP did not receive immunosuppression before, during or after HIP islet cell transplantation. The NHP showed tightly controlled blood glucose levels and was completely insulin independent for six months. Following anti-CD47 mediated ablation of the graft, blood glucose levels increased steadily. Insulin injections were resumed eight days after the start of anti-CD47 antibody at the previously established maintenance dose. Despite insulin supplementation, widely fluctuating blood glucose levels were observed and no steady state was re-established for the remainder of the study.

Data published in Hu et al., 2024, Cell Stem Cell 31, 334–340.

Hypoimmune Islet Cells Normalize C-peptide Levels after Allogeneic Transplantation in a Fully Immunocompetent NHP

NHP serum C-peptide declines after induction of diabetes post STZ. As early as one week after the transplantation, NHP serum c-peptide level normalized (indicated by c-peptide levels of >2ng/ml) and remained stable throughout the follow-up period of six months. Destruction of HIP islet cells by anti-CD47 antibody coincides with the decline in C-peptide levels in the serum, confirming that HIP islet cells were required for continued production of C-peptide in the NHP.

Data published in Hu et al., 2024, Cell Stem Cell 31, 334–340.

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

The preliminary clinical findings from the first-in-human transplantation of UP421, our HIP-modified allogeneic primary islet cell product, in the IST being conducted at Uppsala University Hospital further validate our preclinical observations. These initial human data demonstrate that HIP-modified islet cells can survive and function without immunosuppression. The detection of C-peptide production and comprehensive immune evasion in the IST represents a significant step toward addressing the fundamental challenge of cellular persistence in transplantation therapies. The preliminary results from the IST are described in greater detail below in the section titled “Pancreatic Islet Cell Program.”

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 when the cells are not in a location where physical removal is feasible. Such a safety switch would mitigate the potential risk of adverse outcomes if a hypoimmune cell, which can, by its nature, evade the immune system, becomes infected with a virus or undergoes oncogenic transformation.

One approach we are exploring as a safety switch is re-sensitization of 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 observedin vitro that the addition of an anti-CD47 antibody binds to and blocks CD47 expressed in the hypoimmune cells and restores their sensitivity to the missing-self killing response mediated by NK cells. We also assessed this strategy in mice that were transplanted with human iPSCs that formed small teratomas. Finally, we have conductedin vitro andin vivo experiments with this strategy using a number of human cancer lines, showing that an anti-CD47 antibody resensitizes cancer cells to killing by NK cells and macrophages. Treatment with an anti-CD47 antibody resulted in the loss of immune evasion and the rapid killing of these transplanted cells. As described above, use of an anti-CD47 antibody in a fully immunocompetent NHP was sufficient to trigger destruction of transplanted allogeneic HIP islet cells following initial survival of such cells for six months. We believe these data support use of anti-CD47 antibodies as a potential safety strategy. We have identified several additional safety switches with bothin vitroandin vivo activity and will include one of these in SC451 to provide another mechanism to kill these cells if needed.

Anti-CD47 Administration Results in the Rapid Clearance of Hypoimmune NHP iPSCsin Vitro

Left panel: Hypoimmune NHP iPSCs do not induce killing by NK cells in an in vitro killing assay. Right panel: 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 iPSC-derived Teratomas in a Humanized Mouse Model

Left panel: Human iPSCs proliferate (as visualized by luminescence of live cells) and form teratomas in NSG mice (n=3) with adoptive transferred human NK cells. Administration of isotype control has no impact on hypoimmune iPSC survival.

Right panel: Blocking of CD47 in vivo results in killing of hypoimmune iPSCs (as visualized by luminescence of live cells) in NSG mice (n=5) with adoptive transferred human NK cells. These results have been confirmed in vivo as illustrated above in the allogeneic HIP islet transplantation experiment conducted in a diabetic NHP.

CD47 Overexpression is Differentiated in Inhibiting “Missing Self” Response Relative to Other Approaches

As part of our ongoing efforts 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 cell line that is naturally deficient in MHC class I and class II, and in which the lack of the MHC class I molecule should result in rapid 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, each of which has previously been thought to play a role in inhibiting innate immune responses, against CD47. In this assay, overexpression of these three molecules conferred limited protection from NK cell killing as compared to CD47 overexpression. This difference in activity may be the result of the more ubiquitous presence of the receptor for CD47 on innate immune cells relative to the presence of receptors for these other immunomodulators. Although 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.

CD47 Overexpression is Differentiated in Inhibiting “Missing Self” Response Relative to Other Approaches

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.

Ourex vivo Cell Engineering Pipeline

Pancreatic Islet Cell Program

SC451 is our hypoimmune PSC-derived pancreatic islet cell product candidate that aims to restore glucose control in patients with T1D patients by transplantation into these patients without the need for immunosuppression. T1D is a disease of missing pancreatic beta cells, and we believe that transplanting pancreatic islets, which are composed of pancreatic alpha, beta, and delta cells, offers the chance for patients to have normal blood glucose control without insulin, meaningfully improving outcomes for patients with T1D. Over 20 years of global clinical experience transplanting allogeneic primary pancreatic islets from cadavers support this belief. After transplant with significant immunosuppression, T1D patients can remain off insulin with well controlled blood glucose for well over a decade. More recently, several groups have shown that transplant of PSC-derived pancreatic islets along with meaningful immunosuppression can lead to normalization of blood glucose with no need for exogenous insulin. Because there are relatively few patients for whom long-term immunosuppression is better than insulin, we believe that creating a hypoimmune product, removing the need for immunosuppression, is the key next step in creating a curative and broadly available therapy for patients with T1D.

In December 2024, the first-in-human transplantation of UP421, our HIP-modified allogeneic primary islet cell product, occurred at Uppsala University Hospital in a Phase 1 investigator-sponsored trial (IST). The IST is designed to evaluate safety, immune evasion, and function of UP421 transplanted intramuscularly without any immunosuppression in a patient with T1D. Four week and preliminary twelve-week clinical data demonstrate that all primary and secondary endpoints were met. The study showed no drug product-related adverse events. Additionally, there was evidence of graft survival by MRI as well as graft survival and function with detectable C-peptide production. Immunological analysis revealed comprehensive immune evasion of HIP-modified pancreatic islet cells. The four-week results and preliminary 12-week results are described in greater detail below.

Background on Type 1 Diabetes Mellitus

T1D is an autoimmune disease in which the patient’s immune system destroys its own pancreatic islet 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,” T1D disease onset commonly occurs in adolescence. Beta cells reside in specialized hormone-producing clusters within the pancreas called the islets of Langerhans. In T1D, 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 lifelong battle to control blood glucose levels. Without insulin therapy, T1D is rapidly fatal. T1D currently affects approximately nine million patients worldwide. These patients represent a small fraction of the overall global diabetes population, which is estimated to be approximately 540 million.

Insulin injection is the main treatment option for T1D. Despite significant advances in types of insulins, glucose monitoring, and insulin pumps, life expectancy for T1D is still approximately 15 years shorter than for people without diabetes. Patients are at risk of acute complications of hyperglycemia, including diabetic ketoacidosis, coma, and death, as well as 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 can 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, though 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, although inconvenient in adults, is a frequent point of failure in adolescents.

Pancreas transplantation for uncontrollable diabetes was first performed in the 1960s and established the principle that replacing the beta cells (here, in the context of the entire 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 requires 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, levels of hemoglobin A1C (a marker of long-term glucose levels) can be normalized, severe episodes of hypoglycemia can be reduced, and the pathology associated with long-term hyperglycemia can halt or even reverse. As with an organ transplant, patients must undergo chronic immune suppression to prevent immune rejection of the transplanted cells. Most patients lose glucose control over a period of months to years and eventually become insulin-dependent again, primarily due to immune rejection of the allogeneic islets resulting from an inability to tolerate the significant immune suppression necessary to protect the cell transplant.

Our Pancreatic Islet Cell Program Approach

The goal of our SC451 program is to restore glucose control in T1D patients by transplanting hypoimmune PSC-derived islet cells, including beta cells, without the need for immunosuppression, giving patients physiologically appropriate glucose sensing and insulin secretion. We believe this therapy could reduce, or even eliminate, hypoglycemia and hyperglycemia in T1D patients, potentially enabling less onerous and costly treatment, fewer complications, a meaningfully improved quality of life, and longer life expectancy.

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

Deriving islet cells from PSCs has the potential to solve limitations associated with use of a donor pancreas and improve the overall product quality and product consistency. PSCs have the potential to create a virtually limitless supply of these cells. Our program uses proprietary differentiation protocols to generate mature islet cells with glucose control comparable to primary human islets, as evidenced by our animal studies. Finally, we are applying our hypoimmune technology to modify the genomes of the PSCs. If successful, we believe the hypoimmune genome modifications will protect these PSC-derived islet cells from both autoimmune and allogeneic rejection by the patient’s immune system and potentially remove the need for toxic immunosuppression in transplant recipients. Hypoimmunity also eliminates the need for physical separation of the islet cells from the rest of the body by a device or encapsulation technology, which may allow for tighter glucose control by eliminating the lag time between glucose sensing and insulin secretion as well as avoiding the fibrotic reaction inherent in encapsulation technologies to date.

Preclinical Data

We are developing a proprietary protocol to differentiate hypoimmune PSCs into mature, glucose-sensitive, insulin-secreting islet cells. We are exploring ways to optimize the differentiation of islet cells at a greater purity and with superior function compared to published stem cell-based protocols. The principal function of beta islet cells, the insulin-secreting cells within an islet, is to maintain steady levels of glucose in circulation. The beta islet cells sense when glucose levels rise in the bloodstream and release insulin in response. We have observed that our PSC-derived islet populations can respond to glucose and secrete insulinin vitro.

These PSC-derived pancreatic islets were tested in a mouse model of T1D induced by the beta cell toxin, STZ. When transplanted into the kidney of the T1D mice, these islet cells normalize glucose levels in an equivalent fashion to primary human islets. The diabetic glucose levels return when the grafts are surgically excised via nephrectomy. Similar to the human phenotype, T1D mice cannot normalize circulating glucose levels following a glucose injection. Following transplantation of our islet cells, these mice rapidly normalized blood glucose in an equivalent fashion to both non-T1D mice and T1D mice that received human primary islet transplants.

We have also tested whether hypoimmune modifications to iPSC-derived islet cells can enable evasion of autoimmune rejection. We approached this question in two ways.

First, we carried out transplantation experiments in the non-obese diabetic (NOD) mouse model, which develops spontaneous T1D due to induction of autoantibodies and autoreactive T cells that kill the islet cells. We isolated islets from pre-diabetic NOD mice and applied hypoimmune technology to these islets to generate hypoimmune NOD islet cells, which we transplanted into diabetic NOD mice. When transplanted into NOD mice, unmodified NOD islet cells were rejected within approximately two weeks and had no impact on the diabetes. By contrast, the hypoimmune NOD islet cells survived and achieved durable glycemic control within two weeks.

In a second set of experiments, we tested whether we would observe similar findings in a human T1D model. A T1D patient has no functioning islets, so we derived a novel model to test the ability to overcome autoimmune recognition and rejection of these cells. First, we reprogrammed immune cells from a T1D patient donor into iPSCs. We then split the iPSCs into two groups – one group to which we applied hypoimmune modifications and one that remained unmodified – before differentiating these iPSCs into islet cells using our differentiation protocol. This process produced two different cell products for testing: (i) hypoimmune iPSC-derived islet cells and (ii) unmodified iPSC-derived islet cells. To simulate the immune environment of a T1D patient, we developed a humanized mouse model (T1D mice) which is populated with immune cells from the same T1D patient donor and in which diabetes is subsequently induced via STZ. Unmodified iPSC-derived islet cells injected intramuscularly into T1D mice were rejected within nine days without any impact on the mouses ability to control blood glucose. In contrast, hypoimmune iPSC-derived islet cells survived in T1D mice and resulted in glucose control within two weeks. To confirm that the immune system was intact and functioning and in these mice, we tested the impact of a subsequent injection of unmodified iPSC-derived islet cells into the mice that had already been injected with hypoimmune iPSC-derived islet cells. We found that the unmodified iPSC-derived islet cells were rapidly rejected while the hypoimmune iPSC-derived islet cells and the glucose control were preserved. Together, these data support our belief that our hypoimmune modifications can enable evasion of autoimmune rejection.

Autologous Pancreatic Islet Experiment

A: Experimental schema for generating a humanized T1D mouse and autologous iPSCs from T1D patient PBMCs. T1D patient PBMCs were used to generate iPSCs, which were used to generate unmodified and hypoimmune autologous islet cells.

B: Unmodified iPSC-derived autologous islet cells are cleared by the immune system of the humanized T1D mouse by day 7 and did not restore glycemic control

C: Hypoimmune iPSC-derived autologous islet cells (injected on left side of mouse) survive for duration of experiment (through day 29) while unmodified iPSC-derived autologous islet cells (injected on right side of mouse at day 15 following injection of hypoimmune iPSC-derived autologous islet cells) are cleared within one week following injection.

Data published in Hu et al., Sci. Transl. Med. 15, eadg5794 (2023) 12 April 2023.

HIP-Modified PSC-derived Islet Cells Transplanted into Muscle Persist and Control Blood Glucose in Mice for Greater than 15 Months

Upper left panel: Single-cell RNA sequencing visualized via a UMAP feature plot showing insulin expression in unedited PSC-derived islet cells. Analysis reveals high insulin expression across stem cell-derived (sc-) islet cells, with peak expression localized within the sc-beta cell cluster.

Upper right panel: Glucose-Responsive Human C-Peptide Production by HIP-Modified PSC Islets In Vivo at 51 Weeks Post-Transplant. HIP-modified PSC islet cells demonstrated sustained functionality through glucose-responsive c-peptide secretion 51 weeks after transplantation (see details of transplantation conditions below). Mice were fasted for five hours, and plasma was collected via tail-snip before (“pre-glucose,” light gray bar) and 30 minutes after (“post-glucose,” dark gray bar) administration of an intraperitoneal 3 g/kg dextrose bolus. Human c-peptide levels, measured in picomoles (pM), increased significantly from a baseline of approximately 800 pM to about 1750 pM following glucose stimulation. Data presented as mean ± S.D.

Lower panel: Long-Term Blood Glucose Control by HIP-Modified PSC Islets. Graph demonstrates the persistent efficacy of HIP-modified PSC islet cells in controlling blood glucose levels for greater than 64 weeks. Nonfasted blood glucose levels were measured following transplantation of PSC-derived islet cells (5x106 cells/mouse) into the right hindlimb muscle of immunodeficient NSG mice (n=5). Diabetes was induced by a five-day, low-dose (45 mg/kg) course of STZ beginning two weeks prior to transplantation. Diabetic (STZ) control mice did not receive PSC-derived islet cells (n=2). Data is presented as mean ± S.E.M.

We are developing SC451, our HIP-modified PSC-derived islet cell product candidate, to be available as an “off-the-shelf” allogeneic therapy that can be administered intramuscularly without immunosuppression.

Single-cell RNA sequencing analysis of our initial PSC-derived islet cell differentiation process demonstrates consistent production of cell populations comprising approximately 60% beta cells, with the remainder consisting of other islet and neuroendocrine cells. Single-cell analysis confirms the absence of residual PSCs in the final product. In vitro studies indicate that HIP modification of PSC-derived islet cells confers immune-evasive properties, which suggests potential utility in the transplantation setting without immunosuppression.

Following intramuscular transplantation into diabetic mice, HIP-modified PSC islet cells have demonstrated survival and function for greater than 64 weeks. Blood glucose normalization was observed within four weeks post-implantation and maintained throughout the study period. Analysis shows glucose-responsive human C-peptide production, indicating regulated insulin secretion. Histological examination at day 458 revealed preserved morphology, C-peptide content, vascularization, and CD47 expression. No tumor formation or other histologic abnormalities were observed throughout the study duration.

In January 2025, we announced positive results from the IST at four weeks after cell transplantation, which demonstrated the survival and function of pancreatic beta cells as measured by the presence of circulating C-peptide, a biomarker indicating that transplanted beta cells are producing insulin. Positive preliminary twelve-week clinical results, building on the four-week results, demonstrate that all primary and secondary endpoints were met. The 42-year-old recipient, who had been living with T1D for over 30 years, received a single transplant of UP421 into the muscle of the forearm. The primary endpoint of safety was achieved with no drug product-related adverse events reported. Prior to transplant, C-peptide levels were undetectable both in the non-fasting state and in response to an MMTT. Pancreatic beta cells produce pro-insulin, which is cleaved and secreted as insulin and C-peptide in a 1:1 ratio, making C-peptide a well-established biomarker of endogenous insulin production. Results of the study at four- and twelve-weeks after cell transplantation demonstrate the survival and function of pancreatic beta cells as measured by the presence of circulating C-peptide. C-peptide levels also increase with an MMTT during testing at these timepoints, consistent with insulin secretion in response to a meal. MRI scanning also demonstrated a sustained signal at the site of transplanted cells over time, which is consistent with graft survival. No inflammation or safety-related signals were observed.

The UP421 drug product contains a mixture of islet cell populations: wild-type (WT) islet cells expressing HLA class I and class II, double knockout (DKO) islet cells with HLA class I and class II eliminated, and HIP islet cells with both HLA class I and class II eliminated plus CD47 overexpression. WT islet cells triggered a robust immune response, with peak T cell activation at day 7 following transplantation, followed by T cell-mediated killing, and development of donor-specific antibodies. DKO islet cells, while avoiding T cell activation and antibody responses, were rapidly eliminated by natural killer (NK) cells. In contrast, HIP islet cells demonstrated comprehensive immune evasion, with no evidence of T cell activation, donor-specific antibody development, or NK cell-mediated killing through twelve weeks. These distinct immune responses were further validated in whole blood assays, where HIP islet cells uniquely survived exposure to the patient's PBMCs while both WT and DKO islet cells were eliminated.

To our knowledge, this study is the first example of successful transplantation with no immunosuppression into a person with an intact immune system to demonstrate survival and function of allogeneic cells. We believe these initial results with HIP-modified cells represent a significant milestone for the field of cell therapy. The results are a key landmark in our effort to develop SC451, our HIP modified stem cell-derived pancreatic islet cell product candidate, as an off-the-shelf cell therapy for patients with T1D. The 12-week data remain subject to source data verification, after which we and our collaborators at Uppsala University Hospital expect to publish in scientific journals and/or present at scientific conferences more details and longer follow-up from this study in 2025 and beyond.

Systemic Detection of C-peptide Levels Demonstrate UP421 Cell Survival

No detectable c-peptide before UP421 transplantation (dotted line: limit of detection). C-peptide is systemically detectable at day 7 following UP421 transplantation and stays stable up to 28, indicating survival of UP421 cells.

Increased C-peptide Levels with a Mixed Meal Tolerance Test Highlight UP421 Cell Survival and Function

Before UP421 transplantation, c-peptide was not detectable in the mixed meal tolerance test (grey line). At 4 weeks after UP421 transplantation, c-peptide increases in the MMTT indicating survival and function of the UP421 islets.

Unmodified Islet Cells do Not Evade T Cell or B Cell Immune Responses

WT islet cells expressing HLA activate recipient’s T cells 7 days after transplantation. Activation declines over time. At baseline, patient’s T cells are not activated by the donor WT islet cells, resulting in no killing of the WT islet cells at the baseline timepoint. When patient’s T cells are activated (7 days and after), the WT islet cells are killed. 7 days after transplantation, donor-specific antibodies of IgM type bind to donor HLA and IgM antibodies switch to IgG around day 14.

dKO Islet Cells Evade T Cell and B Cell Immune Responses but are Killed by NK Cells

dKO islet cells have endogenous CD47 expression and no expression of both HLA I and II molecules. When exposed to patient T cells, these cells neither activate the T cells nor are they killed by the T cells. Additionally, donor-specific antibodies do not bind to dKO islet cells. However, patient NK cells effectively eliminate dKO islet cells at each measured timepoint due to the "missing-self" response

HIP Islet Cells Evade T Cell, B Cell, and NK Cell Immune Responses

HIP islet cells overexpress CD47 and have no expression of HLA I or II. No T cell activation or killing of HIP islet cells is observed by patient’s T cells at any timepoint. No donor-specific antibody binding nor NK cell killing of HIP islets by patient’s immune cells is observed. Data demonstrate that HIP islet cells evade adaptive and innate immune responses.

Next Steps

We expect to submit an IND for SC451 as early as 2026.

Allogeneic T Cell Programs (SC291, SC262)

Our allogeneic T cell programs use T cells from healthy donors to generate CAR T therapies for various targets, including CD19, a protein expressed on the cell surface of B cells, for the potential treatment of patients with B cell mediated autoimmune diseases, and relapsed and/or refractory B cell malignancies. We believe that applying our hypoimmune technology to allogeneic T cells will enable us to create differentiated allogeneic CAR T therapies.

Our most advanced product candidate is SC291, a CD19-directed allogeneic CAR T therapy. In November 2023, we received IND clearance for the clinical study of SC291 in B cell mediated autoimmune diseases, including LN, ERL and ANCA-associated vasculitis, which we refer to as the GLEAM trial, and we expect to share data from this trial in 2025. In January 2024, we received IND clearance to evaluate SC262, a CD22-directed allogeneic CAR T, for the treatment of patients with relapsed and/or refractory B cell malignancies who have received prior CD19-directed CAR T therapy, which we refer to as the VIVID trial, and we expect to share data from this trial in 2025.

Background on B Cell Mediated Autoimmune Disease

Autoimmune diseases arise from immune system dysfunction whereby the body’s immune cells mistakenly attack healthy cells and tissues in the body. These diseases are typically characterized by defects in the adaptive immune response involving B cells and/or T cells. These diseases can manifest across multiple organ systems and lead to a decreased quality of life or even severe disability in patients. B cell depletion has been shown to provide clinical benefit in autoimmune disorders mediated by dysfunctional B cells, including SLE, systemic sclerosis, myositis, multiple sclerosis, ANCA-associated vasculitis, and others. Collectively, these diseases afflict more than 5 million patients in the United States alone.

SLE is a chronic autoimmune disease that predominantly affects women of childbearing age. Immunologic abnormalities, especially the production of antinuclear antibodies (ANA), are a prominent feature of the disease. The exact cause of SLE remains unclear, but it is thought to result from a combination of genetic predisposition and environmental triggers. SLE presents with a wide range of clinical signs and symptoms, as well as serologic findings, and can affect multiple organ systems. SLE has a prevalence of approximately 400,000 across the United States, EU5, and Japan. About 60% of SLE patients are diagnosed with LN after clinical indication of kidney involvement. The remainder are classified as having extrarenal lupus. The renal complications are detected through an abnormal urinalysis arising during the disease course. LN is one of the most severe complications of SLE, in which autoantibodies cause damage to the glomerular structures in the kidney, which can result in end-stage renal disease (ESRD). Patients with ESRD have a 5-year survival rate of 50%.

ANCA-associated vasculitis is a group of diseases characterized by loss of immunological tolerance to neutrophil protein, which causes inflammation of small blood vessels. The primary clinical manifestations of the disease occur in the upper respiratory tract, in the kidneys, or as asthma. The cause of ANCA-associated vasculitis is not fully understood and believed to be in part due to genetic susceptibility and environmental triggers. There are about 60,000 ANCA-associated vasculitis patients in the United States. Left untreated, ANCA-associated vasculitis is associated with significant morbidity, but with proper treatment, the 5-year survival rate ranges from 80% to 90%.

Currently, there is no standard of care treatment for achieving drug-free remission in LN patients; therefore, patients often require life-long therapy. While a combination approach using antimalarials (hydroxychloroquine), systemic steroids, and conventional immunosuppressant medicines (such as azathioprine (AZA), mycophenolate mofetil (MMF), and cyclophosphamide) are first-line options, a significant proportion of patients continue to have high disease activity and recurrent relapses despite therapy.

Rituximab, initially approved by the FDA in 1997 for the treatment of R/R NHL, is a monoclonal antibody (mAb) that selectively targets the B cell specific surface molecule CD20. The LUNAR trial of rituximab failed to meet the primary endpoint of complete renal response after treatment with rituximab, although the trial demonstrated partial responses in selected patients. Complete peripheral depletion of B cells with rituximab was not observed in all participants, and even in participants where complete peripheral depletion of B cells was observed, less than 50% achieved complete response. A retrospective analysis of these data demonstrated that deeper B cell depletion was associated with improved complete renal responses, and that poor tissue B cell depletion was associated with non-response. The continued persistence of autoreactive B cells in protected microenvironments, such as the lymphoid germinal center structures, correlated with the partial success of this approach in LN. Treatments for ERL include low intensity therapies such as low-dose corticosteroids, antimalarials, and NSAIDS.

Based on worsening disease manifestations, additional immunosuppression medications can include high dose prednisone, methotrexate (MTX), AZA, and MMF, which are known to have side effects and increase the risk of significant infection. The pivotal trial of the anti-BAFF mAb belimumab in SLE patients demonstrated a clinically meaningful improvement in patient outcomes in a large trial that enabled the first FDA drug approval for the treatment adult patients with SLE. Although this large trial demonstrated a reduction of disease activity compared to placebo control, approximately 20% in all groups still experienced a severe disease flare. Anifrolumab, a mAb targeting the interferon alfa signature known to be elevated in SLE patients, was approved by the FDA in 2021 for the treatment of adult patients with SLE. Only 15% of the patients met the criteria for remission at 52 weeks, highlighting the unmet need in patients.

Since the 1970s, cyclophosphamide has been the standard of care therapy for ANCA-associated vasculitis, demonstrating a survival benefit compared to corticosteroids alone. However, the dose-limiting toxicity of cyclophosphamide results in treatment failure and risk of chronic relapse. Rituximab was approved for this indication based on a clinical trial in which it was shown to be non-inferior to cyclophosphamide for remission (at six months), supporting the role of B cell depletion in the treatment of these patients. A complement C5a receptor, avacopan, was recently approved in this indication. Despite this recent success and FDA and European Medicines Agency approval, 35-45% of patients do not achieve remission of disease at one year with these new therapies.

There is strong evidence to suggest that B cell depletion with CD19-directed CAR T cell therapy is feasible and highly effective in patients with SLE. In a study published in 2022 from Germany, five SLE patients between 18 and 24 years of age were treated with autologous CD19-directed CAR T cell therapy. These SLE patients had multiorgan involvement and were refractory to a variety of immunosuppressive drug treatments. After lymphodepleting chemotherapy with fludarabine and cyclophosphamide, autologous CD19-directed CAR T cells were administered as a single intravenous infusion.

Full depletion of B cells was observed from peripheral blood in all patients from Day 2 following CAR T cell infusion, resulting in an improvement in clinical symptoms and evidence of decline of ANAs. These data suggest that CD19-directed CAR T cell therapy induces deep B cell depletion in tissues such as lymph nodes and highlights a key advantage in the use of CD19-directed CAR T cell therapy compared to antibody-mediated B cell depletion. All patients achieved remission status by three months, with drug-free remission maintained over a median of eight months. B cells did reappear in these patients after approximately 110 days; however, these B cells were naïve and showed non-class-switched B cell receptors, suggesting elimination of B cell subsets generating autoantibodies and a reset of the B cell repertoire. Despite the reconstitution of B cells, patients did not experience flares of SLE or need additional immunosuppressive medication, indicating the achievement of drug-free remission. As of December 2024, the drug-free clinical remission in the first patient continues almost 40 months following CAR T treatment. Previous studies using CD19-directed CAR T cell therapy in lymphoma and leukemia have reported CRS and ICANS occurring frequently after treatment. However, the five SLE patients receiving CAR T cell therapy had either no reported CRS or only Grade 1 CRS. None of these five patients developed ICANS, indicating low therapy-related toxicity with CAR T cell treatment in these patients. As of ASH 2024, this group had treated a total of 35 patients across three B cell mediated autoimmune diseases, namely SLE, idiopathic inflammatory myositis and systemic sclerosis. Clinical remission was reported across all patients and CAR T treatment was well tolerated without the need for further immunosuppression.

Background on B Cell Malignancies

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. Other common subtypes of NHL include mantle cell lymphoma, follicular lymphoma, and marginal zone B cell lymphoma.

ALL is a type of leukemia that results from an uncontrolled proliferation of lymphoblasts, which are immature white blood cells. 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, and the vast majority of the approximately 1,500 ALL 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 involves cancer cells that express the CD19 protein. The five-year overall survival rate in ALL adults over the age of 60 is approximately 20%, and the median disease-free survival in patients with R/R ALL after two or more lines of therapy 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 of this disease, ALL remains a leading cause of death due to cancer in children.

First-line therapy for NHL typically consists of multi-agent cytotoxic drugs in combination with the monoclonal antibody rituximab. 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 since 2017, 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. Two autologous CD19 CAR T products have been approved in second-line patients with R/R NHL after proving to be superior to standard of care in pivotal trials.

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 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 R/R patients, including proteasome inhibitors, antimetabolites, JAK inhibitors, and monoclonal antibodies, as well as autologous and allogeneic CAR T candidates.

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 these novel therapies, and even if they able to obtain such access, many patients ultimately relapse following treatment and succumb to their cancer,

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

Lack of Response / Relapse. Only about 50% of patients treated with an approved CD19-directed CAR T therapy will have a complete response and approximately one-third of patients with a complete response will relapse relatively quickly. The emerging post-approval data from approved CAR T therapies tisagenlecleucel, axicabtagene ciloleucel and lisocabtagene maraleucel indicate that relapse can result from one of two primary factors.

The first involves loss of CD19 expression on malignant cells, resulting in tumor escape. This finding was initially established for ALL and is the cause of relapse after CAR T treatment for roughly half of treated patients. More recent data indicate that low CD19 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 that more patients will be treated with CD19 CAR T therapy and subsequently relapse due to CD19 loss. Patients with CD19 therapy failure have an extremely poor prognosis, with overall survival measurable in months and virtually no treatment options. Therefore, the development of CAR T therapies targeting an antigen other than CD19 may provide an opportunity 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 failed to reach a complete response or relapsed after CD19 CAR T treatment.

The second pattern of relapse relates to suboptimal CAR T cell functionality, such as poor expansion, poor persistence, or T cell exhaustion, resulting in relapse and continued growth of cancer cells that retain the targeted antigen. Re-infusion with the same CAR T therapy has had limited benefit in these patients, although treatment with a different CAR T therapy has demonstrated some promise in ongoing clinical trials.

Manufacturing. Because autologous CAR T therapies are patient-specific products, their manufacturing process is complex and requires significant resources, including time and labor. Given this, infrastructure and cost considerations and limitations have resulted in limited patient access to these therapies. Even for patients who are fortunate enough to have access to approved CAR T therapies, delays, commonly of at least one month, resulting from scheduling difficulties and issues that arise during manufacturing may prevent use of and the utility of these therapies in patients with rapidly progressing malignancies. Certain groups are seeking to overcome access limitations by using healthy donor-derived, or allogeneic, CAR T cells instead of patient T cells to yield “off-the-shelf” therapeutics that can be manufactured consistently. However, efficacy and durability concerns remain, largely due to the inability to effectively control the HvGR response and the risk of eventual immune rejection of these products by the recipient. We are developing ourex vivo allogeneic T cell programs to address this HvGR and prevent immune rejection.

Limitations of Other Allogeneic CAR T Therapies

We believe our hypoimmune cells have the potential to create a differentiated platform for developing allogeneic T cells, and to address two major hurdles associated with use of allogeneic T cells. The first is the risk of GvHD, in which the allogeneic donor T cells target and kill recipient tissues. Multiple CAR T cell product candidates in clinical development have prevented 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 address 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. However, this strategy has two limitations. First, the patient is at risk for developing severe infections during this period of substantial immune suppression. Second, as the immune system returns following immune suppression, it will inevitably reject the allogeneic CAR T cells, limiting their persistence, or the duration that these therapeutic cells are in the body. In multiple independent clinical trials, regardless of the disease setting, allogeneic CAR T cells have been shown to be cleared from the patient immune system in less than a month despite high dose immunosuppression. The therapy recipients often experience short lived clinical responses with the lack of durability correlating with the poor persistence of the allogeneic cells. Conversely, the clinical experience with autologous CAR T cells has demonstrated that longer persistence of the CAR T correlates with durable cancer remission. Thus, the ability to effectively prevent long-term rejection of an allogeneic CAR T therapy without significant immune suppression would provide a significant advantage over existing allogeneic approaches. We are aware of other efforts to develop allogeneic CAR T cell products that focus on overcoming the adaptive immune system, consisting of T and B cells. However, our hypoimmune technology addresses rejection mediated by both the adaptive and innate immune systems, which we believe will enable us to create a differentiated allogeneic CAR T solution.

Our Allogeneic T Cell Approach

Our hypoimmune technology is designed to “hide” the cell from the patient’s immune system, and we are applying this technology for the clinical development of hypoimmune allogeneic CAR T cells for a variety of therapeutic applications. Our allogeneic T cell platform is designed to enable the substitution of CAR constructs in a modular fashion. Initial clinical success with SC291 would support the expansion of our allogeneic CAR T efforts and enable additional product candidates to be brought forward and developed. We are prioritizing clinically-validated antigens as well as CAR constructs that have shown robust safety and efficacy profiles in hematologic malignancies in the autologous context.

Our manufacturing process begins with T cells from healthy donors, into which we introduce the CAR gene, make the gene modifications necessary to avoid GvHD, and incorporate our hypoimmune modifications to prevent host versus graft disease. We then expand these cellsex vivo, which enables us to both make many batches from a single T cell donor as well as create comparable CAR T cells derived from different donors. Our vision is to freeze these allogeneic CAR T therapies, store them, and deliver them to patients as an “off the shelf” product without requiring severe immunosuppression.

SC291 Treatment Results in Deep B Cell Depletion in Non-Hodgkin’s Lymphoma Patients

CD19+ B cells levels are depleted below the limits of quantification for all NHL patients treated with SC291 at dose levels 3 and 4 up to day 28. Figure shows quantification of CD19+ B cells levels in the peripheral blood five days before infusion (D-5) and post dosing starting at day 0. The dashed horizontal lines indicate lower limit of the quantification (5 cells/uL).

GLEAM is a Phase 1 clinical trial evaluating SC291 in patients with LN, ERL, and ANCA-associated vasculitis. Clinical studies conducted by third parties evaluating B cell depleting agents in B cell mediated autoimmune disease have established that deep B cell depletion is an important correlate of clinical activity, with deeper B cell depletion correlating with better clinical activity for the agents.

We have also studied SC291 in patients with B cell malignancies in a trial we refer to as ARDENT, in which we have seen a generally tolerable safety profile. Among sixteen patients, we observed no cases of Grade 2 or higher CRS, of any Grade ICANS, or of GvHD. We observed a single case of Grade 1 IEC-HS. All six evaluable NHL patients treated at the two highest cell dose cohorts showed deep B cell depletion. We are optimistic that if we observe safe and deep B cell depletion in the GLEAM study similar to that observed in these cohorts of the ARDENT study, then SC291 could have a meaningful clinical benefit for patients in the autoimmune indications being evaluated in GLEAM. In December 2024, the U.S. FDA granted Fast Track designation for SC291 in SLE, which includes LN and ERL. Fast Track designation is designed to facilitate development and expedite review of drugs that address serious conditions and unmet medical needs.

Development Plan and Key Next Steps

We expect to report progress on the GLEAM trial, in which we are evaluating SC291 in LN, ERL, and ANCA-associated vasculitis, in 2025. The potential for B cell depletion with SC291, as seen in ARDENT, may provide clinical benefit to patients with B cell mediated autoimmune disease. We also plan to share data from our VIVID trial, in which we are evaluating SC262 in patients with relapsed and/or refractory B cell malignancies who have received prior CD19-directed CAR T therapy, in 2025.

Ourin vivo Cell Engineering Platform

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 toin vivo cell engineering:

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Delivering any payload (such as DNA, RNA, proteins, organelles, integrating versus non-integrating, size),

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to any cell (by increasing the volume of distribution),

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in a specific (for instance just T cells), and

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repeatable way (such as achieving limited immunogenicity to allow re-dosing).

Ourin 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 quantitiesin vivo. The combination of a fusogen with a delivery vehicle, is 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 forin vivo therapies.

Our Approach to Building Our in vivo Cell Engineering Platform

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

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Delivery. We believe the critical limitation forin vivo cell engineering is delivery, and therefore, we are investing significantly in delivery technologies, including our fusogen technology, which is designed to enable both cell-specific delivery and delivery of diverse payloads.

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Gene modification. There has been substantial recent progress in gene modification and the field is now at the point at which virtually any desired modification can be performedin vitro. However, no single technology or platform is optimal for all possible applications. To this end, we are developing capabilities across multiple technologies and investing to develop our own novel technologies to be applied on a case-by-case basis.

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Manufacturing. We are investing proactively in process development, analytical development, chemistry, manufacturing, and controls (CMC) regulatory, supply chain, quality, and other manufacturing sciences in order to enable scalable manufacturing of ourin vivo therapies and ensure broad access.

We have prioritized cell types for our programs when:

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existing proof of concept in humans and animal models demonstrates thatin vivo cell engineering should have a clinical benefit;

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high unmet need can be addressed by modifying a particular cell type;

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delivery is the most critical bottleneck, such that delivering payloads specifically to the target cell type could lead to highly differentiated and transformative therapeutics; and

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an opportunity to apply the technology more broadly exists, which creates the potential for more medicines if successful.

Based on this prioritization, we are initially focused on T cells.

History of in vivo Cell Engineering and Current Limitations

The gene therapy field began decades ago with experiments on transmitting genetic payloads via viral vectors. Despite significant investments improving viral vector safety and efficacy, most approaches still adapt viruses' innate payload transmission capabilities. Although profound benefits have been realized when therapeutic biological activity directly correlates with missing genetic activity—particularly using Adeno-Associated Virus (AAV) vectors prized for their broad tissue tropism and ability to target both dividing and non-dividing cells—these therapies have only scratched the surface ofin vivo cell engineering's potential, with success limited to a small number of patients. The broader impact ofin vivo therapies has been limited by challenges related to payload delivery, genome modification and manufacturing execution.

Payload delivery in gene therapy faces several critical challenges:

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Limited cell specificity: Commonly used AAV vectors have broad tissue specificities, making it difficult to target specific cells and potentially causing toxicity in non-target cells. Lipid nanoparticles (LNPs) typically target any cell expressing the LDL receptor, making them both non-specific and mainly absorbed by hepatocytes in the liver when dosed systemically. Recent progress in re-targeting LNPs may allow for better delivery to cells beyond the liver, although meaningful liver absorption likely occurs.

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Limited volume of distribution: Even when using AAV vectors for systemic delivery, therapeutically important targets like CNS cells see only limited transduction.

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Immunogenicity: Viral vectors trigger immune responses that attack the vector, with pre-existing antibodies further limiting efficacy and often preventing re-dosing opportunities.

Genome modification challenges include:

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Payload size and type restrictions: The natural genome size of viral vectors (e.g., AAV's maximum capacity of 4.5-5kb) is insufficient for many disease targets that require larger payloads or gene editing machinery. Payloads with LNPs are typically even more limited.

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Durability limitations: Immune reactions, silencing of vector expression, and gradual loss of vector sequences in replicating cells compromise long-term therapeutic effects.

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Payload type constraints: Both viral and non-viral delivery methods face constraints on the types of genetic material they can effectively transport. Non-viral delivery with LNPs has largely been limited to RNA and proteins to date, with scant evidence for DNA delivery.

Manufacturing execution faces substantial hurdles:

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Complex manufacturing processes: Viral vector-based therapies are significantly more difficult to characterize, and control compared to recombinant proteins and antibodies.

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Limited scale-up capabilities: Process and analytical sciences that enable meaningful scale-up lag behind other biologically-derived modalities.

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Restricted yield and access: Current vector manufacturing limitations ultimately restrict patient access to these potentially transformative therapies.

Our Solution – Fusogen Technology

To address some of the existing challenges ofin 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.

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 found in 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 using 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.

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 can 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 because altering the protein structure directly impacts all aspects of biological function. However, once we have achieved the desired specificity and potency of the G protein 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.

Addressing Key in vivo Cell Engineering Challenges

We believe that ourin vivo cell engineering platform enables us to address key challenges associated with successfulin 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, potentially enabling delivery of a payloadin vivo to transduce specific T cell populations and enabling targeted cell killing through the creation of CAR T cells.

Broad volume of distribution. We have invested in investigating approaches to expand the volume of distribution of fusosomes.

Immunogenicity. We are initially focusing our efforts on selecting fusogens for which the general population does not have pre-existing immunity.

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. Using VLPs, we have shown that we can deliver a variety of genome modification tools specifically to a cell. We believe this capability provides us the opportunity to potentially intervene in a wide range of human diseases.

Fusosomes can Deliver Genome-Modifying Payloads in a Cell-Specific Manner

A: Fusosome-mediated delivery and integration of CAR transgene to CD8+ T cells in vivo. NSG mice (N=5/group) engrafted with NALM6-ffluc tumor cells and human PBMCs (IV, day -3) were treated with a fusosome targeting CD8+ T cells delivering a CD19 CAR transgene (day 0). Untreated, PBMC alone or tumor alone engrafted animals were used as controls. Peripheral blood samples were analyzed by flow cytometry on day 14 for expression of CD19 CAR in CD8+ T cells.

B: Fusosome-mediated delivery of base editing machinery to hepatocytes in vivo. In this study, fusosomes with a broadly tropic fusogen (VSV-G) were engineered to deliver a nuclease and gRNA as ribonucleic protein as a virus-like particle (VLP), with the gRNA recognizing TTR target locus. Fusosomes were dosed into FAH-/- Rag2 -/- IL2rg-/- (FRG) humanized liver mouse model, where human hepatocytes are engrafted in the mouse liver. Mice were injected via IV and gene editing was assessed in the liver after approximately two weeks. Fusosomes enabled genetic modification of 56% of alleles of the TTR gene in engrafted primary human hepatocytes and a corresponding 55% reduction of circulating human TTR protein in the mice as measured by ELISA.

C: Fusosome-mediated delivery of Cas9 nuclease machinery to target cells in vitro. Fusosomes with a broadly tropic fusogen (BaEVTR) were engineered to deliver a nuclease and gRNA as ribonucleic protein as a VLP, with the gRNA recognizing B2M target locus. Treatment of resting cord blood CD34+cells with fusosome resulted in 80-90% B2M knockout cells (as measured by flow cytometry 7 days post addition of fusosome), corresponding to up to 93% of edited alleles as measured by high-throughput sequencing of the B2M locus. Two different batches of fusosomes were tested on CD34+ cells from the same donor and are represented as “Study 1” and “Study 2” in the figure.

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 for our fusosomes to address defects in larger genes or conditions when delivery of multiple genes may be required. Our research efforts include other fusosomes with even larger payload capacities. For example, we are exploring using a cell as the delivery vehicle, which can confer an almost limitless capacity.

Durability limitations. We can engineer our fusosomes to deliver payloads that integrate into the target cell genome or that are non-integrating. 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 diseases arising from issues in essential genes that are functioning in growing tissues, or in T cell expansion occurring following target antigen recognition, can be better addressed through use of integrating payloads. Our preclinical studies have also demonstrated the ability of our fusosome system to deliver non integrating gene-editing machinery, such as CRISPR, with this system. In this case, the entire payload does not integrate, but instead, this payload transiently delivers the machinery to permanently modify the DNA in the target cell, enabling us 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 payloadsin vivohas the potential to create autologous, gene-modified cells without the complexities ofex 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 forex vivo modification of autologous and allogeneic T cells. Additionally, vectors that deliver payloads 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- and long-term, including by establishing and maintaining our relationships with our contract development manufacturing organizations (CDMO) partners and continuing to establish our internal manufacturing capabilities. Manufacturing novel fusosome compositions is complex. Since our inception, we have invested in improving the manufacturing of our therapies, including by investing in in scientific and process engineering aspects thereof. Our investments include use of novel producer cell lines, novel processes, and analytical technology, as well as incorporating suspension bioreactors into our manufacturing processes early in the research phase. By building out these capabilities early, we hope to improve the probability of technical success for our programs, which will enable us to deliver consistent supply while managing cost of goods and improve patient access.

Ourin vivo Cell Engineering Pipeline

T Cell Fusosome Program (SG299)

Our most advanced CAR T cell fusosome product candidate is SG299, a CD8-targeted fusosome that delivers a CD19-directed CAR to target CD19+ cancer cells that we are developing to treat patients with hematologic malignancies and autoimmune diseases.

T Cell Fusosome Approach

Our T cell fusosome approach provides us with an opportunity to develop CAR T cell therapies that can be more broadly accessible to patients than treatments that are currently available. We also believe that the ability to deliver a payload encoding a CAR to a T cell inside the body has the potential for improved effectiveness overex 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 in patients that receive autologous CAR T cell therapies with conditioning lymphodepletion. Our first fusosome program will deliver the CAR gene using fusogens that directly and specifically target the CD8 co-receptor on T cells following a single intravenous injection. We believe that this approach could result in the generation of therapeutically active CAR T cells without the complexities and delays associated with the process of T cell collection andex vivo manufacturing. We may target the CD4 co-receptor in future programs. Furthermore, ex vivo expansion in the presence of high cytokine concentrations, although 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 anin vivo CAR T cell, within the natural physiological environment, has the potential to improve the quality of the CAR T cell generated, which may ultimately improve both efficacy and the side effect profile. Finally, the effectiveness ofex 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 use a lymphodepleting regimen prior toin 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, as well as in immunodeficient mice with intraperitoneally-injected human peripheral blood mononuclear cells (PBMCs) that have been infused 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 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 proteinsin vitro.

Fusogens Demonstrate the Ability to Target Multiple T Cell Subtypes

Fusosomes can efficiently and specifically deliver GFP, which is used to identify cells that have been genetically modified by the fusogen, to three different types of 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).

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. We have also validated, in vivo, the tumor-killing activity of CD8+ T cells to which a CD19 CAR has been delivered via a fusosome. 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 T cells, cytokine signaling must be activated in order to successfully produce functional CAR T cells. In our mouse experiments the CD8-targeted fusosome was able to generate CD19-directed CAR T cells just as effectively with activated as non-activated donor T cells.

SG299’s CD8-targeting fusogen cross reacts with CD8 in most NHP species. In a GLP toxicology study conducted innemestrina macaques, a single intravenous injection of SG299 demonstrated selective, dose-dependent gene delivery to target CD8+ T cells as measured by integrated vector copy number. The level of gene delivery is consistent with up to 20% of target cells receiving CAR transgene at the highest dose level. Tissue analysis showed minimal to no quantifiable presence in non-target tissues, including the liver and gonadal tissue. No infusion-related toxicity or CAR-associated toxicity (cytokine release syndrome or neurotoxicity) was observed.

To evaluatein vivo CAR T generation and B cell depletion, we developed a surrogate SG299 that delivers a CD20 CAR capable of targeting NHP B cells incynomolgus macaques. No lymphodepletion was administered to the NHPs in this study. Following a single intravenous injection of SG299 combined with an additional component, CAR-positive T cells reached peak expansion around day 7 following injection, with approximately 30-45% of circulating T cells expressing the CAR. CAR transgene-positive T cells remained detectable in circulation beyond three weeks. Deep B cell depletion was achieved in peripheral blood and maintained for at least four weeks post-injection, with B cell clearance confirmed in lymph node biopsies at day 28. B cell phenotype analyses performed after peripheral B cells returned show a “B cell reset,” with a predominance of naïve B cells in circulation.

Taken together, these results suggest that SG299 can be safely dosed in NHPs and has the potential to deliver a CAR transgene that can result in deep and durable depletion of B cells without lymphodepletion.

Transduction of Circulating CD8+ T cells by SG299 in NHPs

No Off-Target Transduction of Hepatocytes or Gonadal Cells by SG299 in NHPs

Cell-specific in vivo delivery demonstrated with SG299 in GLP toxicology study: Nemestrina macaques were injected intravenously with a high or low dose of SG299, and in vivo generated CAR T cells were monitored by analysis of vector copy number (VCN) of the CD19 CAR transgene.

Upper panel: VCN in enriched CD8+ cells in peripheral blood. N=4 up to day 35 and N=2 from day 35 to 90 for each group.

Lower panel: VCN in total tissue lysates. N=2 for each group. Mean+/-SD plotted, values above LOQ were graphed. Vehicle control animals (N=2) were BLOQ in both peripheral blood and tissues.

Surrogate SG299 with Additional Component can Transduce CD8+ T Cells in NHPs with Expansion over 7-14 Days

Surrogate SG299 and Additional Component Results in Deep B cell Depletion in Peripheral Blood in NHPs

Surrogate SG299 with additional component leads to T cell transduction, CAR expansion, and B cell depletion. Cynomolgus macaques were injected intravenously with a SG299 surrogate delivering a CD20 CAR transgene in combination with an additional component. Presence of CAR-T cell and B cells were evaluated by flow cytometry up to 28 days post-fusosome treatment.

Upper panel: Cellular kinetics of CD8+ CAR+ cells in peripheral blood.

Lower panel: CD20+ B-cell counts per volume of blood (uL) in peripheral blood. N=3 for vehicle control, N=2 for SG299 surrogate plus additional component. Mean+/-SD of the controls and individual treated animals shown.

Surrogate SG299 and Additional Component Results in Deep B cell Depletion in Peripheral Blood in NHPs

B-cell clearance in lymph nodes without lymphodepletion. Lymph nodes from cynomolgus macaques injected intravenously with an SG299 surrogate delivering a CD20 CAR transgene in combination with an additional component. Biopsy performed on day 28 post-injection in one control animal and two treated animals. Tissues were analyzed by immunohistochemistry. Brown, anti-CD20; blue, hematoxylin; black, tattoo ink.

Development Plan and Key Next Steps

We are working to finalize the product composition, perform GMP manufacturing of SG299, and conduct other critical activities for an IND. We anticipate our initial study with SG299 will be in the oncology setting followed rapidly by a study in B cell mediated autoimmune disease. Importantly, this therapy offers the potential for cell-specific delivery and CAR T activity with no lymphodepleting chemotherapy. We anticipate submitting an IND for SG299 as early as 2026.

Manufacturing Strategy and Approach

Although 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.

We have developed a manufacturing strategy with early investments in people, technology, and infrastructure, which requires:

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establishing a team with diverse, experienced talents with extensive knowledge of both the process and analytical sciences in the field of cell and gene therapy, as well as CMC product development expertise from preclinical to global commercialization;

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establishing multiple manufacturing platforms for our diverse portfolio; and

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establishing infrastructure from lab bench to a GMP manufacturing and supply chain network.

To support our development pipeline, we have established process development for allogeneic T cells and PSC-derived therapies. Although our manufacturing processes for these therapies vary, they also share some common challenges and opportunities. For example, product characterization and analytical development are critical, and these capabilities are largely fungible across processes. In addition, we are focusing on some of the key areas in each of our processes to enable scaled manufacturing. For the allogeneic T cell therapies, 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 islet 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.

Our non-GMP pilot plant for engineered cell platform processes has up to 200L bioreactor scale. This provides the infrastructure for process and technology development, technology transfer support, and production for non-GMP material such for GLP toxicology studies. We expect to use CDMOs for initial GMP supply to support our upcoming INDs and clinical trials and anticipate we will use CDMOs for at least some portions of our supply chain for the foreseeable future. In June 2022, we entered into a long-term lease to establish and develop our own GMP manufacturing facility to support the manufacturing of product candidates across our product portfolio, such as the production of allogeneic T cells.

Competition

Other companies have stated that they are developing cell and gene therapies that may address type 1 diabetes, B cell mediated autoimmune disorders, and oncology. 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 Allogene Therapeutics, Inc., Bristol-Myers Squibb Company, Cabaletta Bio, Inc., Caribou Biosciences, Inc., Cargo Therapeutics, Inc., Century Therapeutics, Inc., CRISPR Therapeutics AG, Eli Lilly and Company, Fate Therapeutics, Inc., Gilead Sciences, Inc., Interius BioTherapeutics, Inc., Johnson & Johnson, Kyverna Therapeutics, Inc., Legend Biotech Corporation, Novartis AG, Novo Nordisk A/S, Roche Holding AG, Umoja Biopharma, Inc., and Vertex Pharmaceuticals Inc., might be conducting large-scale clinical trials for therapies that could be competitive with ourex vivo andin vivo programs. Among companies pursuingex vivoandin vivo cell engineering, we believe we are substantially differentiated by our robust intellectual property portfolio, extensive research, rigorous and objective approach, and multidisciplinary capabilities.

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 will 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 ourex vivo andin vivo cell engineering platforms and related product candidates, including related manufacturing processes. As of January 2025, our in-licensed and owned patent portfolio consisted of approximately 45 licensed or owned U.S. issued patents, approximately 57 licensed United States pending patent applications, and approximately 86 owned U.S. pending patent applications, as well as approximately 74 licensed patents issued in jurisdictions outside of the United States, approximately 263 licensed patent applications pending in jurisdictions outside of the United States, and approximately 312 owned patent applications pending in jurisdictions outside of the United States (including approximately 30 owned pending Patent Cooperation Treaty (PCT) applications) that, in many cases, are counterparts to the foregoing United States 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 may 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 non-provisional 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 term of a United States patent that covers an FDA-approved drug may also be eligible for patent term extension, which recaptures a portion of the term effectively lost as a result of the testing and regulatory review periods required by the 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. 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 January 2025 have terms expected to expire on dates ranging from 2028 to 2042. If patents are issued on our patent applications pending as of January 2025, the resulting patents are projected to expire on dates ranging from 2028 to 2045. 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 validity and enforceability of the patent, and the availability of legal remedies in a particular country.

In some instances, we submit patent applications directly to the USPTO as provisional patent applications. Provisional patent applications 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 this 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 application. While we intend to timely file non-provisional 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 United States non-provisional 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 158 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.

We determine claiming strategy for each patent application on a case-by-case basis. We always consider the advice of counsel and our business model and needs. We file patent applications containing claims for protection of all useful applications of our proprietary technologies and any product candidates, as well as all new applications 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 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 platforms. 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 area of patent and other intellectual property rights in biotechnology is an evolving one with many risks and uncertainties. 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 positions of companies outside of the United States can be 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, our issued patents do not guarantee us the right to practice our technology in relation to the commercialization of our products, as 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.

As of January 2025, our registered trademark portfolio contained approximately 26 registered trademarks and pending trademark applications, consisting of approximately one pending trademark application and three registered trademarks in the United States, and approximately 18 registered trademarks and approximately four 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, the United Kingdom, 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 ourex vivo andin 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 derivedex 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 rights 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 use these license rights in ourex vivo cell engineering platform 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 United States 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 (which converted to shares of our common stock in connection with our initial public offering) 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 $20,000 for 2019, $50,000 for 2020, and $100,000 for each of 2021, 2022, 2023, 2024, and 2025, 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 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, 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. Pursuant to the terms of the Harvard agreement, we may be required to make up to an aggregate of $175.0 million in success payments to Harvard (Harvard Success Payments), payable in cash, based on increases in the per share fair market value of our common stock. The potential Harvard Success Payments are based on multiples of increasing value ranging from 5x to 40x based on a comparison of the per share fair market value of our common stock relative to the original issuance price of $4.00 per share at ongoing pre-determined valuation measurement dates. The Harvard Success Payments can be achieved over a maximum of 12 years from the effective date of the agreement. If a higher success payment tier is met at the same time a lower tier is met, both tiers will be owed. Any previous Harvard Success Payments made are credited against the Harvard Success Payment owed as of any valuation measurement date so that Harvard does not receive multiple success payments in connection with the same threshold. As of December 31, 2024, a Harvard Success Payment had not been triggered.

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 United States and international patents and patent applications (UCSF Patent Rights) by The Regents. The license grants us rights 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 use these license rights in ourex vivo cell engineering platform that relies on our hypoimmune technology.

We are obligated, directly or through affiliates or sublicensees, 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 inventions, 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 reservation of rights 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 (which converted to shares of our common stock in connection with our initial public offering). 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 effective date of the UCSF Agreement to $40,000 on the sixth anniversary and continuing annually thereafter. This fee will not be due if we are selling or exploiting licensed products or licensed services and paying an earned royalty to The Regents on net sales of such licensed products or licensed services. We are also required to pay The Regents up to an aggregate of $2.45 million per licensed product upon the achievement of certain 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 with percentages 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 for 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) 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 United States government, including the requirement that licensed products sold in the United States be substantially manufactured in the United States.

Pursuant to the 2019 WU Agreement, we paid Washington University an upfront license issue fee of $75,000. We are required to pay Washington University up to $100,000 per year 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 $6.0 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 as a percentage of annual net sales of WU Hypoimmune Products 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 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 under the licensed patent rights, which we expect to occur in 2038. We 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 use these license rights in ourex vivo cell engineering platform that relies on our hypoimmune technology, including our pancreatic islet 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 United States government, including the requirement that licensed products sold in the United States be substantially manufactured in the United States.

Pursuant to the 2020 WU Agreement, we paid Washington University an upfront license issue fee of $150,000. We are required to pay Washington University up to $100,000 per year in license maintenance fees on each anniversary of the 2020 WU Agreement’s effective date until the first commercial sale of a licensed 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 per licensed product for the first three licensed products under the 2020 WU Agreement, for an aggregate of $6.0 million in development and regulatory milestones. Additionally, of certain commercial milestones, we are required to pay Washington University up to an aggregate of $4.5 million 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 obligated to pay royalties as a percentage of annual net sales of licensed products 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 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 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 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 progenitorex vivo cell engineering program, in exchange for $8.5 million in cash, net of certain expenses. 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 specified development and commercial milestones, which we may pay in cash or in shares of our common stock, subject to certain conditions. In November 2024, we announced a portfolio prioritization pursuant to which we suspended development of our glial progenitor cell-based therapy program (GPC Program) and as a result, do not expect to achieve such milestone events or pay the associated milestone amounts. As a result of the Oscine acquisition, we entered into, or obtained and amended, licenses to various technologies related to our glial progenitor cell-based therapy program, including a license agreement with University of Rochester.

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 under the prior 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. Historically, we used these license rights in the development of our GPC Program. Our suspension of development of the GPC Program resulted in a termination of the Rochester Agreement and reversion to the University of Rochester of the rights granted to us thereunder.

License Agreement with Beam

In October 2021, we entered into an option and license agreement (as amended, 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 originally had 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. We subsequently amended the Beam Agreement in July 2022 to extend the term of the option period and to add certain additional rights to the scope of the license for the purpose of supporting research and development of licensed products, and amended the Beam Agreement again in March 2023 to further extend such option period. In April 2024, we further amended the Beam Agreement to further extend such option period and increase the amount of the option payment, and we subsequently amended the Beam Agreement, effective October 2024, to replace certain antigen targets. In addition, we may (i) until the expiration of such option period, 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) for a period of three years from the effective date of the Beam Agreement, 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 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 $50.0 million. Additionally, with respect to each licensed product, we will be obligated to pay to Beam up to $65.0 million in specified developmental and commercial milestones. 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 Institution, 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 certainin vivo gene therapy andex 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 with respect to each licensed product, and (ii) a payment of $1.0 million 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 FDA with respect to a licensed product, we will be obligated to pay to the NIH the greater of (i) $5.0 million 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 expire 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, 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. Pursuant to the terms and conditions of the Cobalt acquisition agreement, we are obligated to pay to certain former Cobalt stockholders contingent consideration (Cobalt Contingent Consideration) of up to an aggregate of $500.0 million upon our achievement of certain pre-specified development milestones and a success payment (Cobalt Success Payment) of up to $500.0 million, each of which is payable in cash or stock. The Cobalt Success Payment is payable 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 biologics license application or new drug application for a product based on the fusogen technology. A valuation measurement date would also 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. If there is a change of control and our market capitalization is below $8.1 billion as of the date of such change of control, the amount of the potential Cobalt Success Payment will decrease, and the amount of potential Cobalt Contingent Consideration will increase. 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 use the rights granted by Flagship under the Flagship Agreement in our fusogen platform and related 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 expire on the expiration of the last-to-expire royalty term, which is determined on a Fusogen Product-by-Fusogen Product and jurisdiction-by-jurisdiction basis, and occurs on 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 and Pulsalys subsequently amended this agreement in July 2023 and October 2024.

We use the rights granted under the Pulsalys Agreement in ourin vivo fusogen 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 a certain period of time following the effective date of the Pulsalys Agreement, and (ii) submitting an IND within a certain period of time following 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. These retained rights do not affect our ability to pursue our programs and product candidates.

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 865,000 EUR upon the achievement of such development 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 expire 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.

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 use the rights granted under the UCLA Agreement in ourin vivo fusogen 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 demand. 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. In May 2021 and April 2024, we and UCLA amended the UCLA Agreement to extend the timelines by which we are required to achieve certain of such milestones. Pursuant to the April 2024 amendment, we agreed to pay UCLA a fee of $100,000 for such extension, as provided under the terms of the original UCLA Agreement.

The license granted pursuant to the UCLA Agreement is subject to certain rights retained by the California Institute for Regenerative Medicine (CIRM) and the United States government, including a non-exclusive, royalty-free license granted to the United States 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. These retained rights do not affect our ability to pursue our programs and product candidates.

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 subsequently increases 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 United States government to the extent required by law, and we will be required to reduce the amount charged for licensed products distributed to the United States 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 such challenge fails, 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 against such challenge, including attorney’s fees.

The UCLA Agreement will expire 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 (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:

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completion of preclinical laboratory tests and animal studies performed in accordance with the FDA’s Good Laboratory Practice requirements (GLPs) and other applicable regulations;

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submission to the FDA of an Investigational New Drug application (IND), which must become effective before clinical trials may begin;

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approval by an institutional review board (IRB), or ethics committee at each clinical site before the trial is commenced;

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performance of adequate and well-controlled human clinical trials to satisfy the FDA’s legal standards with respect to the safety, purity, and potency of the proposed product candidate, which may include, among other things, demonstrating that the benefits of the product candidate outweigh its known risks for the intended patient population;

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preparation of and submission to the FDA of a biologics license application (BLA), after completion of all pivotal clinical trials;

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satisfactory completion of an FDA Advisory Committee review, if applicable;

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a determination by the FDA within 60 days of its receipt of a BLA to file the application for review;

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satisfactory completion of an FDA pre-approval inspection of the manufacturing facility or facilities at which the proposed product is processed, packed, or held to assess compliance with current Good Manufacturing Practices (cGMP), and to assure that the facilities, methods, and controls will continue to meet the FDA’s legal requirements, and, if applicable, to assess compliance with the FDA’s current Good Tissue Practice (cGTP) requirements for the use of human cellular and tissue products, and of selected clinical investigation sites to assess compliance with Good Clinical Practices (GCPs); and

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FDA review and approval of the BLA to permit commercial marketing of the product for particular indications for use in the United States.

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 andin 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.

In addition to the IND submission process, under the National Institutes of Health Guidelines for Research Involving Recombinant DNA Molecules (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. Although 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. While the IND is active, progress reports summarizing the results of the clinical trials and nonclinical studies performed since the last progress report, among other information, must be submitted at least annually to the FDA, and written IND safety reports must be submitted to the FDA and investigators for serious and unexpected suspected adverse events, findings from other studies suggesting a significant risk to humans exposed to the same or similar drugs, findings from animal orin vitro testing suggesting a significant risk to humans, and any clinically important increased incidence of a serious suspected adverse reaction compared to that listed in the protocol or investigator brochure.

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:

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Phase 1—The investigational product is initially introduced into healthy human subjects or patients with the target disease or condition. These studies are designed to test the safety, dosage tolerance, absorption, metabolism and distribution of the investigational product in humans, the side effects associated with increasing doses, and, if possible, to gain early evidence on effectiveness.

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Phase 2—The investigational product is administered to a limited patient population with a specified disease or condition to evaluate the preliminary efficacy, optimal dosages and dosing schedule and to identify possible adverse side effects and safety risks. Multiple Phase 2 clinical trials may be conducted to obtain information prior to beginning larger and more expensive Phase 3 clinical trials.

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Phase 3—The investigational product is administered to an expanded patient population to further evaluate dosage, to provide statistically significant evidence of clinical efficacy and to further test for safety, generally at multiple geographically dispersed clinical trial sites. These clinical trials are intended to establish the overall risk/benefit ratio of the investigational product and to provide an adequate basis for product approval.

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, sponsors 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.

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 for a product candidate to determine, among other things, whether the information provided satisfies the FDA’s legal standards with respect to the safety, purity, and potency of the proposed product candidate, which may include, among other things, demonstrating that the benefits of the product candidate outweigh its known risks for the intended patient population. The FDA also reviews a BLA to determine whether the facility in which it is manufactured, processed, packed, or held meets standards designed to assure that the product candidate will continue to meet the FDA’s legal requirements. 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.

After the FDA evaluates a BLA and conducts any inspections it deems necessary, 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.

In addition, the Pediatric Research Equity Act (PREA) requires a sponsor to conduct pediatric clinical trials for most drugs for a new active ingredient, new indication, new dosage form, new dosing regimen, or new route of administration. Under PREA, original BLAs and supplements must contain a pediatric assessment unless the sponsor has received a deferral or waiver. In general, the required assessment must evaluate the safety and effectiveness of the product for the claimed indications in all relevant pediatric subpopulations and support dosing and administration for each pediatric subpopulation for which it is determined that there is substantial evidence that the product provides benefits that outweigh its known and potential risks. The sponsor or FDA may request a deferral of pediatric clinical trials for some or all of the pediatric subpopulations. A deferral may be granted for several reasons, including a finding that the drug is ready for approval for use in adults before pediatric clinical trials are complete or that additional safety or efficacy data need to be collected before the pediatric clinical trials begin. The FDA must send a non-compliance letter to any sponsor that fails to submit the required assessment, keep a deferral current, or submit a request for approval of a pediatric formulation.

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 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 BLA is eligible for priority review if the product candidate 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 confirmatory 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 confirmatory studies in a timely manner 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 the 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 or condition for which it has such designation, the product is entitled to orphan drug exclusivity, which means that the FDA may not approve any other applications, including a full BLA, to market the same biologic for the same disease or condition 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 disease or condition 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. Recently, the court in Catalyst Pharms., Inc. v. Becerra, 14 F.4th 1299 (11th Cir. 2021) (Catalyst) held that orphan drug exclusivity blocks approval of another company’s application for the same drug for the entire disease or condition for which the drug is granted orphan drug designation, regardless of whether the drug was approved only for a narrower use or indication. However, in January 2023, the FDA published a notice in the Federal Register in response to the Catalyst decision to clarify that while the agency complies with the court’s order in Catalyst, the FDA intends to continue to apply its longstanding interpretation of the regulations to matters outside of the scope of the Catalyst order – that is, the agency will continue tying the scope of orphan drug exclusivity to the uses or indications for which a drug is approved, which permits other sponsors to obtain approval of a drug for new uses or indications within the same orphan-designated disease or condition that have not yet been approved. It is unclear how future litigation, legislation, agency decisions, and administrative actions will impact the scope of the orphan drug exclusivity.

Further, in June 2024, the U.S. Supreme Court overruled the Chevron doctrine, which gave deference to regulatory agencies’ statutory interpretations of ambiguous federal laws in litigation against these agencies, including the FDA. This landmark Supreme Court decision may invite more companies or other stakeholders to bring lawsuits against the FDA to challenge longstanding decisions and policies, which could lead to uncertainties in the industry. Changes in the leadership of the FDA and other federal agencies under the new presidential administration may lead to new policies and legislative, regulatory, and other governmental changes that may impact our clinical development plans.

FDA Regulation of Companion Diagnostics

We or our collaborators may develop an in vitro diagnostic (IVD) to identify appropriate patient populations for investigation or use of our product candidates. These diagnostics, often referred to as companion diagnostics, are regulated as medical devices. In the United States, the Federal Food, Drug, and Cosmetic Act and its implementing regulations, and other federal and state statutes and regulations govern, among other things, medical device design and development, preclinical and clinical testing, premarket clearance or approval, registration and listing, manufacturing, labeling, storage, advertising and promotion, sales and distribution, export and import, and post-market surveillance. Unless an exemption applies, diagnostic tests require marketing clearance or approval from the FDA prior to commercial distribution. The two primary types of FDA marketing authorization applicable to a medical device are premarket notification, also called 510(k) clearance (or decision to grant a De Novo classification request if there is no predicate device), and premarket approval (PMA). The FDA classifies medical devices as Class I, Class II, or Class III devices according to their level of risk, with Class III devices being those with the highest risk. This classification of medical devices affects whether the device will require 510(k) clearance or PMA prior to marketing. In January 2024, the FDA announced its plans to reclassify certain high-risk in vitro diagnostics, including companion diagnostics, as Class II devices. As such, to the extent we or our collaborators develop a companion diagnostic, it may be regulated as a Class II or Class III medical device, depending on its intended use and technical characteristics, among other factors.

If use of companion diagnostic is deemed essential to the safe and effective use of a drug product, then the FDA generally will require approval or clearance of the diagnostic contemporaneously with the approval of the therapeutic product. On August 6, 2014, the FDA issued final guidance titled "In Vitro Companion Diagnostic Devices” addressing the development and approval process for such devices. According to the guidance, for novel product candidates, a companion diagnostic device and its corresponding drug candidate should be approved or cleared contemporaneously by the FDA for the use indicated in the therapeutic product labeling. The guidance also explains that a companion diagnostic device used to make treatment decisions in clinical trials of a drug generally will be considered an investigational device unless it is employed for an intended use for which the device is already approved or cleared. If used to make critical treatment decisions, such as patient selection, the diagnostic device may be considered a significant risk device under the FDA’s Investigational Device Exemption (IDE) regulations, in which case the sponsor of the diagnostic device will be required to submit and obtain approval of an IDE application and subsequently comply with the IDE regulations. However, according to the guidance, if a diagnostic device and a drug are to be studied together to support their respective approvals, both products can be studied in the same investigational study if the study meets both the requirements of applicable IDE regulations and the IND regulations. The guidance provides that, depending on the details of the study plan and degree of risk posed to subjects, a sponsor may seek to submit an IND alone, or both an IND and an IDE.

510(k) Clearance Process

To obtain 510(k) clearance, a premarket notification is submitted to the FDA demonstrating that the proposed device is substantially equivalent to a previously cleared 510(k) device or a device that was in commercial distribution before May 28, 1976 for which the FDA has not yet required the submission of a PMA application. The FDA’s 510(k) clearance process may take three to 12 months from the date the application is submitted and filed with the FDA, but it may take longer if, among other reasons, the FDA requests additional information, which can significantly prolong the review process. In some cases, the FDA may require clinical data to support substantial equivalence. Notwithstanding compliance with all of the 510(k) clearance requirements, such clearance is never assured.

After a device receives 510(k) clearance, any subsequent modification of the device that could significantly affect its safety or effectiveness, or that would constitute a major change in its intended use, will require a new 510(k) clearance or require a PMA. In addition, the FDA may make substantial changes to industry requirements, including which devices are eligible for 510(k) clearance, which may significantly affect the review and approval process.

De Novo Classification Process

If a new medical device does not qualify for the 510(k) premarket notification process because no predicate device to which it is substantially equivalent can be identified, the device is automatically classified into Class III. The Food and Drug Administration Modernization Act of 1997 established a different route to market for low- to moderate-risk medical devices that are automatically placed into Class III due to the absence of a predicate device called the “Request for Evaluation of Automatic Class III Designation,” or the De Novo classification process. This process allows a manufacturer whose novel device is automatically classified into Class III to request down-classification of its medical device into Class I or Class II on the basis that the device presents low or moderate risk rather than requiring the submission and approval of a PMA. If the manufacturer seeks reclassification into Class II, the manufacturer must include a draft proposal for special controls that are necessary to provide a reasonable assurance of the safety and effectiveness of the medical device. The FDA may reject the reclassification petition if it identifies a legally marketed predicate device that would be appropriate for 510(k) premarket notification or determines that the device is not low- to moderate-risk and requires PMA or that general controls would be inadequate to control the risks and special controls cannot be developed.

PMA Process

The PMA process, including the gathering of clinical and preclinical data and the submission to and review by the FDA, can take several years or longer. It involves a rigorous premarket review during which the applicant must prepare and provide the FDA with reasonable assurance of the device’s safety and effectiveness and information about the device and its components regarding, among other things, device design, manufacturing, and labeling. PMA applications are subject to an application fee. In addition, PMAs for certain devices must generally include the results from extensive preclinical and adequate and well-controlled clinical trials to establish the safety and effectiveness of the device for each indication for which FDA approval is sought. In particular, for a diagnostic, a PMA application typically requires data regarding analytical and clinical validation studies. As part of the PMA review, the FDA will typically inspect the manufacturer’s facilities for compliance with the Quality System Regulation (QSR), which imposes elaborate testing, control, documentation, and other quality assurance requirements. The FDA issued a final rule in February 2024 replacing the QSR with the Quality Management System Regulation (QMSR), which incorporates by reference the quality management system requirements of ISO 13485:2016. The FDA has stated that the standards contained in ISO 13485:2016 are substantially similar to those set forth in the existing QSR. The FDA will begin to enforce the QMSR requirements upon the QMSR effective date of February 2, 2026.

Approval of a PMA submission is not guaranteed, and the FDA may ultimately respond to a PMA submission with a not approvable determination based on deficiencies in the application and require additional clinical trial or other data that may be expensive and time-consuming to generate and that could substantially delay approval. If the FDA’s evaluation of the PMA submission is favorable, the FDA typically issues an approvable letter requiring the applicant’s agreement to specific conditions, such as changes in labeling or specific additional information, such as submission of final labeling, in order to secure final approval of the PMA. If the FDA’s evaluation of the PMA submission or manufacturing facilities is not favorable, the FDA will deny approval of the PMA submission or issue a not approvable letter. A not approvable letter will outline the deficiencies in the application and, where practical, will identify what is necessary to make the PMA approvable. The FDA may also determine that additional clinical trials are necessary, in which case approval of the PMA submission may be delayed for several months or years while the trials are conducted and then the data submitted in an amendment to the submission. If the FDA concludes that the applicable criteria have been met, the FDA will issue a PMA for the approved indications, which may be more limited than those originally sought by the applicant. The PMA can include post-approval conditions that the FDA believes necessary to ensure the safety and effectiveness of the device, including, among other things, restrictions on labeling, promotion, sale, and distribution. Once granted, a PMA may be withdrawn by the FDA if compliance with post-approval requirements, conditions of approval, or other regulatory standards are not maintained or problems are identified following initial marketing.

Obtaining FDA marketing authorization, De Novo down-classification, or approval for medical devices is expensive and uncertain, may take several years, and generally requires significant scientific and clinical data.

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:

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restrictions on the marketing or manufacturing of the product, complete withdrawal of the product from the market or product recalls;

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fines, warning letters, or untitled letters;

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clinical holds on clinical studies;

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refusal of the FDA to approve pending applications or supplements to approved applications, or suspension or revocation of product license approvals;

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product seizure or detention, or refusal to permit the import or export of products;

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consent decrees, corporate integrity agreements, debarment or exclusion from federal healthcare programs;

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mandated modification of promotional materials and labeling and the issuance of corrective information;

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the issuance of safety alerts, Dear Healthcare Provider letters, press releases and other communications containing warnings or other safety information about the product; or

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injunctions or the imposition of civil or criminal penalties.

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 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.

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.

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 that the product meets the FDA’s legal standards with respect to safety, purity, and potency, which may include, among other things, demonstrating that the benefits of the product outweigh its known risks. 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, which may constrain the financial arrangements and relationships through which we conduct 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.

Healthcare Reform

The United States government and other governments have shown significant interest in pursuing health care reform. Any government-adopted reform measures could adversely impact the pricing of health care products and services in the United States or internationally and the amount of reimbursement available from governmental agencies or other third-party payors. For example, the Patient Protection and Affordable Care Act (the ACA) which was enacted in the United States in 2010, 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:

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increased the minimum level of Medicaid rebates payable by manufacturers of brand name drugs from 15.1% to 23.1% of the average manufacturer price;

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expanded the manufacturer Medicaid rebate obligation to drugs paid by Medicaid managed care organizations;

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required manufacturers to participate in a coverage gap discount program, under which they must agree to offer 70 percent point-of-sale discounts off negotiated prices of applicable brand drugs to eligible beneficiaries during their coverage gap period, as a condition for the manufacturer’s outpatient drugs to be covered under Medicare Part D; and

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imposed a non-deductible annual fee on pharmaceutical manufacturers or importers who sell “branded prescription drugs” to specified federal government programs.

Since its enactment, there have been judicial, executive, and Congressional challenges to certain aspects of the ACA. On June 17, 2021, the United States Supreme Court dismissed the most recent judicial challenge to the ACA without specifically ruling on the constitutionality of the ACA. Thus, the ACA will remain in force in its current form. Other legislative changes have been proposed and adopted since the ACA was enacted, including reductions of Medicare payments to providers through 2032. The American Rescue Plan Act of 2021 eliminated the statutory Medicaid drug rebate cap. Elimination of this cap may require pharmaceutical manufacturers to pay more in rebates than they receive from the sale of products, which could have a material impact on our business.

Most significantly, on August 16, 2022, President Biden signed the Inflation Reduction Act of 2022 (IRA) into law. This statute marks the most significant action by Congress with respect to the pharmaceutical industry since adoption of the ACA in 2010. Among other things, the IRA requires, beginning in 2026, that manufacturers of certain drugs to engage in price negotiations with Medicare, with prices that can be negotiated subject to a cap; imposes rebates, first due in 2023, under Medicare Part B and Medicare Part D to penalize price increases that outpace inflation; and, beginning in 2025, replaces the Part D coverage gap discount program with a new discounting program. The IRA permits the Secretary of the Department of Health and Human Services to implement many of these provisions through guidance, as opposed to regulation, for the initial years. Only high-expenditure single-source drugs that have been approved for at least seven years (11 years for single-source biologics) can qualify for negotiation, with the negotiated price taking effect two years after the selection year. For 2026, the first year in which negotiated prices become effective, CMS selected ten high-cost Medicare Part D drugs in 2023, negotiations began in 2024, and the negotiated maximum fair price for each drug has been announced. CMS has selected 15 additional Medicare Part D drugs for negotiated maximum fair pricing in 2027. For 2028, up to an additional 15 drugs, which may be covered under either Medicare Part B or Part D, will be selected, and for 2029 and subsequent years, up to 20 additional Part B or Part D drugs will be selected. Various industry stakeholders, including certain pharmaceutical companies and the Pharmaceutical Research and Manufacturers of America, have initiated lawsuits against the federal government asserting that the price negotiation provisions of the IRA are unconstitutional. The impact of these judicial challenges and any future healthcare measures and agency rules, including those implemented by the new presidential administration, on us and the pharmaceutical industry as a whole is unclear. The implementation of cost containment measures or other healthcare reforms may prevent us from being able to generate revenue, attain profitability, or commercialize our product candidates, if approved.

Moreover, there has been recent heightened governmental scrutiny over the manner in which manufacturers set prices for their marketed products, which is likely to continue. 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. For example, the FDA has authorized the state of Florida to develop a drug importation program to import certain prescription drugs from Canada for a limited period to help reduce drug costs, provided that Florida’s Agency for Health Care Administration meets the requirements set forth by the FDA. Other states may follow Florida. We expect that additional state and federal healthcare reform measures will be adopted in the future, any of which could limit the amounts that federal and state governments will pay for healthcare products and services, which could result in reduced demand for our product candidates, if approved, or additional pricing pressures.

Similar political, economic, and regulatory developments are occurring in the European Union (EU) and may affect the ability of pharmaceutical companies to profitably commercialize their products. In addition to continuing pressure on prices and cost containment measures, legislative developments at the EU or member state level may result in significant additional requirements or obstacles. The delivery of healthcare in the EU, including the establishment and operation of health services and the pricing and reimbursement of medicines, is almost exclusively a matter for national, rather than EU, law and policy. National governments and health service providers have different priorities and approaches to the delivery of healthcare and the pricing and reimbursement of products in that context. In general, however, the healthcare budgetary constraints in most EU member states have resulted in restrictions on the pricing and reimbursement of medicines by relevant health service providers. Coupled with ever-increasing EU and national regulatory burdens on those wishing to develop and market products, this could restrict or regulate post-approval activities and affect the ability of pharmaceutical companies to commercialize their products. In international markets, reimbursement and healthcare payment systems vary significantly by country, and many countries have instituted price ceilings on specific products and therapies.

On December 13, 2021, Regulation 2021/2282 on Health Technology Assessment (HTA) amending Directive 2011/24/EU (the Regulation), was adopted. Although the Regulation entered into force in January 2022, from January 31, 2025, or the end of the transition period, any trials approved under the Clinical Trials Directive that continue running must comply with the Regulation, and their sponsors must enter information regarding the trials in the Clinical Trials Information System. The Regulation intends to boost cooperation among EU member states in assessing health technologies, including new medicinal products, and providing the basis for cooperation at the EU level for joint clinical assessments in these areas. The Regulation will permit EU member states to use common HTA tools, methodologies, and procedures across the EU, working together in four main areas, including joint clinical assessment of the innovative health technologies with the most potential impact for patients, joint scientific consultations whereby developers can seek advice from HTA authorities, identification of emerging health technologies to identify promising technologies early, and continuing voluntary cooperation in other areas. Individual EU member states will continue to be responsible for assessing non-clinical (e.g., economic, social, and ethical) aspects of health technology, and making decisions on pricing and reimbursement.

We expect that additional state, federal, and foreign healthcare reform measures will be adopted in the future, any of which could limit the amounts that federal and state governments will pay for healthcare products and services, which could result in reduced demand for our product candidates once approved or additional pricing pressures.

Employees and Human Capital Resources

As of December 31, 2024, we had 194 employees, 145 of whom were primarily engaged in research and development activities. A total of 111 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, with respect to our employees, cash-based performance bonus awards.

In November 2024, we announced a portfolio prioritization to prioritize clinical and preclinical development in type 1 diabetes, B-cell mediated autoimmune diseases, refractory B-cell malignancies, and the fusogen platform for generatingin vivo CAR T cells. We suspended development of SC291, our HIP-modified CD19 allogeneic CAR T therapy, in oncology and SC379, our glial progenitor cell program, as we seek partnerships for these programs. We anticipate that the portfolio update and associated workforce reduction will be substantially complete in the first quarter of 2025, after which we expect to have approximately 160 employees.

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 iswww.sana.com. The information on, or that can be accessed through, our website is not part of this Annual 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. We also make available on or through our website certain reports and amendments to those reports that we file with or furnish to the SEC in accordance with the Exchange Act. These include our Annual Reports on Form 10-K, our quarterly reports on Form 10-Q, and our current reports on Form 8-K, and amendments to those reports filed or furnished pursuant to Section 13(a) or 15(d) of the Exchange Act. We make this information available on or through our website free of charge as soon as reasonably practicable after we electronically file the information with, or furnish it to, the SEC. The SEC also maintains a website that contains our SEC filings. The address for the SEC website iswww.sec.gov.