NASDAQ: SANA

We are currently focused on advancing two distinct therapeutics, each of which leverages one of these platform technologies. SC451 is our HIP-edited product candidate for the treatment of type 1 diabetes. SG293 is our in vivo CAR T product candidate for the treatment of B cell malignancies and B cell mediated autoimmune diseases.

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Type 1 Diabetes: Almost ten million people suffer from type 1 diabetes (T1D) worldwide, and there has been limited progress in treatments for this disease since the advent of insulin injections over 100 years ago. 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. Through a first-in-human investigator-sponsored study (IST), we have shown that UP421, an allogeneic, primary islet cell therapy engineered with our HIP technology, can survive and function for twelve months post-transplant in a patient with T1D without the need for immunosuppression. We have incorporated this HIP technology into a more scalable manufacturing platform with SC451 and expect to file an investigational new drug application (IND) as well as begin a Phase 1 clinical trial for this therapy as early as this year.

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In vivo CAR T cells: Using our fusogen platform, which enables cell-specific, in vivo delivery of various payloads, we are developing SG293, a CD8-targeted fusosome. SG293 delivers genetic material to CD8+ T cells, which enables them to become CD19-targeting CAR T cells while avoiding potentially problematic delivery to tissues such as the liver and gonads. In vivo CAR T cells have the potential to provide the clinical benefit of autologous, ex vivo manufactured CAR T cells while avoiding the need for lymphodepleting chemotherapy as well as significant complexity and delays related to manufacturing. SG293 builds on data from our prior lead in vivo CAR T product candidate, SG299. We plan to develop SG293 in a range of B cell cancers and B cell mediated autoimmune diseases and expect to generate initial clinical data as early as this year.

SC451 is our lead program for T1D. T1D is a disease in which the patient’s immune system attacks and kills the patient’s pancreatic beta cells, the only cells in the human body that make insulin, leading to a complete loss of insulin production in affected individuals. Insulin is essential for normal cellular metabolism, and prior to the discovery of insulin replacement therapy over 100 years ago, a person typically died within months of diagnosis. Insulin therapy has meaningfully improved patient outcomes, but even with state-of-the-art medical care and technology and glucose control, a person with T1D will live approximately a decade less than somebody without the disease and have a significant treatment burden for life. In contrast, our goal is to develop a one-time treatment that leads to normal blood glucose with no insulin injections and no immunosuppression, in an effort to restore the patient to a life similar to that from before the T1D diagnosis. Pancreatic islets are comprised of pancreatic beta cells and other endocrine cells. Scientists have shown that transplanted pancreatic islets can allow patients to come off insulin and maintain normal blood glucose. These islets can be obtained from deceased donors or derived from stem cells. However, the impact of these therapies has been limited, as patients must remain on life-long systemic immunosuppression to prevent the patient’s immune system from rejecting these transplanted cells. The potential complications of immunosuppression, which include increased susceptibility to infection, heightened cancer risk, cardiovascular disease, metabolic syndrome, chronic kidney disease, and osteoporosis, outweigh the potential benefits of these treatments in most patients.

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Our HIP technology is designed to hide transplanted cells from immune recognition and rejection. In addition to extensive pre-clinical testing, the ability of our HIP technology to hide transplanted pancreatic islets from immune recognition and rejection has been demonstrated in a human.

In December 2024, UP421, a HIP-modified allogeneic primary islet cell therapy, was transplanted into a patient with T1D in an IST conducted at Uppsala University Hospital. This study evaluates the safety of UP421 when transplanted intramuscularly into a patient with T1D. Secondary endpoints include immune evasion, non-fasting C-peptide concentrations in peripheral blood, C-peptide response to a mixed meal tolerance test (MMTT), and graft survival assessed by magnetic resonance imaging (MRI) and Positron Emission Tomography (PET/MRI). 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. 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 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 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. In September 2025, 12-week data from the IST were published in The New England Journal of Medicine. In addition, we recently reported that at 12 months following transplantation, the UP421 first-in-human study continues to demonstrate durable safety, survival, and function of the transplanted HIP-modified primary islet cells. 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. Results of the study through twelve months following transplantation demonstrate the survival and function of pancreatic beta cells as measured by the presence of circulating C-peptide. C-peptide levels also increased with an MMTT during testing at these timepoints, consistent with insulin secretion in response to a meal. PET/MRI imaging results at 12 weeks and 12 months are consistent with pancreatic beta cell survival and function in the forearm muscle of the patient.

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. We performed assays testing the patient’s various immune cell responses to these different populations of cells in the drug product. Consistent with expectations post-transplantation of allogeneic tissue, WT islet cells triggered a robust immune response with 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. These distinct immune responses were further validated in whole blood assays, in which HIP islet cells survived exposure to the patient's peripheral blood mononuclear cells (PBMCs) while both WT and DKO islet cells were eliminated. These in vitro assay results are consistent throughout the 52 weeks of the study to date. For additional information on the genetic modifications discussed above, see the sections titled “Background on Immunological Barriers to ex vivo Therapies and Current Limitations,” “Our Solution – Hypoimmune Technology,” and “Designing Hypoimmune Cells” below.

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 results with HIP-modified cells represent a significant milestone for the field of cell therapy. These cells not only had to overcome the typical rejection of allogeneic cells, they also needed to overcome the pre-existing autoimmune response to pancreatic beta cells. 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.

UP421 is derived from the cells of a deceased donor. In contrast, SC451 is derived from stem cells and is therefore more amenable to commercial scale. We have made meaningful progress with SC451 over the past year. We have completed manufacture of our gene-modified stem cell master cell bank, begun tech transfer of our Phase 1 manufacturing process to our partner contract manufacturers, continued our necessary preclinical tests, and met with regulators in various parts of the world. We expect to submit an IND for SC451 and begin our Phase 1 trial as early as this year.

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With respect to our in vivo cell engineering research efforts, we have advanced from our earlier SG299 in vivo CAR T candidate to an improved next-generation product candidate, SG293, both of which use our proprietary fusogen-based delivery platform. In January 2026, we shared data from a preclinical study using a surrogate for SG293 that delivers a CD20 CAR capable of targeting non-human primate (NHP) B cells in cynomolgus macaques. No lymphodepletion was administered to the NHPs in this study. A single intravenous injection of the SG293 surrogate to these NHPs resulted in robust in vivo generation of CAR T cells and deep B cell depletion in the peripheral blood and lymph nodes. The B cell depletion was further confirmed by lymph node biopsies showing clearance of B cells as well as by “reset” of the NHPs’ B cell repertoire toward naïve B cells. We believe that deep B cell depletion in this preclinical model is the most significant biomarker for potential efficacy in patients with B cell cancers and B cell mediated autoimmune diseases. Separately, in vitro studies using SG293 have shown selective gene delivery to CD8+ T cells with minimal or undetectable off-target transduction in tissues such as the liver and gonadal tissue, supporting the specificity of SG293. We continue to evaluate SG293 preclinically, and we intend to begin clinical testing and generate early clinical data with SG293 in certain B cell cancers as early as this year. For additional information, see the section titled “T Cell-Targeted Fusosome Approach” below.

Previously, we were also pursuing programs in the field of HIP-edited ex vivo CAR T therapy. However, in order to prioritize development of our SC451 and SG293 programs, in November 2025, we announced our decision to suspend development of our allogeneic CAR T programs, including SC291 and SC262, and to halt further enrollment in the Phase 1 GLEAM and VIVID trials of these candidates. While the allogeneic CAR T programs increased our confidence in our HIP platform, we believe the impact we can have for patients and shareholders is now greater with increased focus on SC451 and SG293.

Our people are the most important strength of the company and our capabilities enable us to take a comprehensive approach to the most important and difficult aspects of engineering cells. We believe we can capitalize on the shared expertise and infrastructure between our ex vivo and in vivo cell engineering platforms to maximize the potential success and 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 (PSCs) 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 our ex vivo and in vivo cell engineering portfolio. Our hypoimmune technology has the potential to “hide” cells from the immune system, unlocking the potential of allogeneic ex 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 cancer and autoimmune diseases.

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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 to 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 and manufacturing 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.

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Ex vivo Cell Engineering

Engineering cells ex vivo requires the ability to engineer and manufacture cells at scale and then deliver them to the patient so that they engraft, function appropriately, and have the necessary persistence in the body. Our goal for ex vivo cell engineering is to replace 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. Our ex 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. Our goal is to manufacture genetically modified cells that are capable of both replacing the missing cell and evading the patient’s immune system. While SC451 is our primary ex vivo candidate, we intend to apply our ex vivo cell engineering technologies to make cell products for the treatment of multiple diseases.

In vivo Cell Engineering

Engineering cells in vivo requires the development of both an appropriate delivery vector as well as a payload to effectively modify the target cell. Our goal for in vivo cell engineering is to repair and control the genes of any cell in the body. The ultimate aim is to achieve 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. Our in 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 our ex vivo and in 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 our ex vivo and in 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 currently focused on advancing our pipeline across two platforms for the treatment of various significant disease types, including type 1 diabetes, B cell cancers, and B cell mediated autoimmune diseases. We retain worldwide rights to each of the product candidates described below.

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.

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iPSC-derived HIP Pancreatic Islet Cells

SC451

SC451 is our induced PSC (iPSC)-derived hypoimmune pancreatic islet cell product candidate for the treatment of diabetes, with an initial focus on T1D. Almost ten 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. T1D patients typically need to take multiple insulin injections and monitor their blood glucose 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. Even for patients with access to state-of-the-art medical care and who are able to tightly control blood glucose through access to automated insulin delivery systems, life expectancy is approximately a decade shorter than for those without the disease.

Previous results from others have shown that either primary or PSC-derived pancreatic islets, when given with significant immunosuppression, can allow patients to control blood glucose without the need for insulin therapy. Based on our human clinical data and preclinical HIP data, we believe that our HIP-modified pancreatic islets should achieve the same outcome without the risks of immunosuppression.

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. The UP421 IST has shown that our hypoimmune cells induce no systemic immune response, survive, and function in a person with T1D. We are combining these capabilities and learnings into SC451 in a single product candidate that is derived from an O-negative, GMP-compliant iPSC master cell line. 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 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 the autoimmune immune response, survive, and function for the duration of the study. Combined, we believe that these studies preclinically validate that our HIP technology can allow transplanted cells to evade both the allogeneic rejection typical with transplantation as well as the autoimmune rejection typical of T1D.

We believe our HIP-modified, iPSC-derived pancreatic islets have the potential to create a disruptive treatment for T1D, offering patients long-term normal blood glucose without immunosuppression. We plan to submit an IND and begin our Phase 1 clinical study as early as this year.

HIP Primary Islet Cells

UP421

UP421 is a HIP-modified allogeneic primary islet cell therapy 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 treated patient are discussed below in the section titled “Pancreatic Islet Cell Program.”

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In vivo CD19-Directed CAR T Cells

SG293

Our in vivo CAR T pipeline has advanced beyond our earlier constructs, such as SG299, to our next-generation product candidate, SG293, which leverages our proprietary fusogen delivery platform to enable direct, in-patient generation of CAR T cells. SG293 uses a CD8-targeted fusogen to deliver a CD19-directed CAR to CD8+ T cells in vivo and is being developed for the treatment of B cell cancers and B cell mediated autoimmune diseases. The goal of our in vivo CAR T platform is to expand the CAR T therapy access to patients and improve the overall safety profile of this therapy while maintaining or improving the efficacy of ex vivo-manufactured, autologous CAR T cell therapies. As an example, the effectiveness of ex vivo-manufactured CAR T cells currently depends on the administration of a lymphodepleting chemotherapy preparative regimen prior to infusion to facilitate expansion of the CAR T cell product post-infusion, and this chemotherapy often has an adverse safety impact. We do not expect to need a lymphodepleting regimen prior to in vivo delivery of the CAR gene via fusosome, and in fact believe that it would be detrimental to our goal of exposing 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 significant ex vivo manipulation has the potential to be more effective and potent than ex 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 and ex vivo manufacturing that are used in currently approved autologous CAR T cell products. Furthermore, the ex 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 environment in vivo has the potential to improve the quality of the CAR T cell generated, potentially improving both efficacy and the side effect profile. We expect to generate initial human data with SG293 as early as this year.

Our ex vivo Cell Engineering Platform

Overview

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 to ex 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.

Our ex vivo cell engineering platform seeks to address these four challenges and is focused on engineering hypoimmune cells that engraft, function, and persist in patients by evading immune rejection. These 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 our ex 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 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.

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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 of ex 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. We are also investing to obtain, manufacture, and ensure access to high quality current good manufacturing practice (GMP)-grade PSC lines for our programs.

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Manufacturing. We are investing 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 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 plan to continue investing in our manufacturing capabilities to ensure our pipeline needs are met.

We have prioritized cell types for our programs where:

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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 appropriately in 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 our hypoimmune technology is a critical missing element to developing an impactful cell therapy.

Based on this prioritization, we are currently focused on pancreatic islet 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, immune rejection of the donated organs, and side effects from immunosuppressive regimens have limited the impact of these procedures beyond blood transfusions.

Host versus graft reaction (HvGR) is an effectively universal reaction whereby the immune system of an organ or cell transplant recipient recognizes the donor tissue as foreign and attacks it, leading to transplant rejection. 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 the impact of these regimens.

Ultimately, the field has looked for a scalable source of therapeutic cells that can be accessed broadly at a manageable cost and 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 that ex 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), iPSCs, and donor-derived cells. Our portfolio currently focuses on cells derived from iPSCs.

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 of ex vivo engineered cells for a broad patient population.

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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 cultured in vitro and grown through cycles of cell division, known as passages, until a line of cells is established that can proliferate without differentiating and retain 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 in ex 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 stem cells. These iPSCs, which we use in SC451, 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 UP421, comes from mature donor-derived allogeneic cells. These cells are neither pluripotent nor from an infinitely renewable source, but are instead obtained as mature cells from human donors.

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 (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.

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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 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 currently focused on applying the hypoimmune technology to iPSCs, which can then be differentiated into multiple cell types. We believe that enabling this capability has the potential to enable ex vivo engineered cells to become an important therapeutic modality.

Some of our scientific founders and their collaborators have worked on creating hypoimmune cells for almost two decades. A key insight that informed their work is the phenomenon of feto-maternal 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 both in vitro and in vivo in 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 hypoimmune technology 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.

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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 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. iPSCs from healthy donors are used as the starting material and are then genetically modified with our 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

Over time, 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 pancreatic islet 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 pancreatic 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 the use of any 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.

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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, function in 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 cells in 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 these 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.

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

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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 Survive in 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).

Data published in Hu et al., Nat Biotechnology 2024 Mar;42(3):413-423.

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

Upper panel: Immune cells from 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.

Data published in Hu et al., Nat Biotechnology 2024 Mar;42(3):413-423.

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.

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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 allograft 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 in 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 ten 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).

Data published in Hu et al., Nat Biotechnology 2024 Mar;42(3):413-423.

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We have also 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 by the NHP’s immune system by 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 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.

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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 of ex vivo therapies, persistence, and thereby unlock waves of potentially disruptive therapies across a variety of cell types.

The findings from the first-in-human transplantation of UP421, our HIP-modified allogeneic primary islet cell therapy, in the IST being conducted at Uppsala University Hospital further validate our preclinical observations. These 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 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 observed in 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 conducted in vitro and in 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 both in vitro and in vivo activity and intend to include one of these in SC451 to provide a mechanism to kill these cells if needed.

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

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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.

Our ex vivo Cell Engineering Pipeline

Pancreatic Islet Cell Program

SC451 is our hypoimmune iPSC-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 deceased donors 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 therapy, occurred in an investigator-sponsored trial (IST) conducted at Uppsala University Hospital. The IST is designed to evaluate safety, immune evasion, and function of UP421 transplanted intramuscularly without any immunosuppression in a patient with T1D. This patient has now been followed for 52 weeks, and data demonstrate that all primary and secondary endpoints have been met throughout the study to twelve months. The study showed no drug product-related adverse events. Additionally, there was evidence of graft survival and function with PET/MRI as well as with detectable C-peptide production throughout the study to twelve months. C-peptide levels increased, as expected, during a mixed meal tolerance test, showing appropriate function of the transplanted islet cells. Immunological analysis revealed comprehensive immune evasion of HIP-modified pancreatic islet cells. Data from the study 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 beta cells. The destruction of these cells leads to complete loss of insulin production and a metabolic disease wherein patients are unable to control their blood glucose levels. Often called “juvenile diabetes,” T1D disease onset commonly occurs in adolescence, but can occur throughout life. 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 almost ten million patients worldwide.

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Current Treatment Landscape and Unmet Need

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 seizures, coma, or death. The significant swings in blood glucose with exogenous insulin make it difficult for a T1D patient to keep blood glucose in physiologic ranges, with blood glucose levels often above target. 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. Automated insulin delivery systems, which feature a computerized system for sensing blood glucose and delivering appropriate doses of insulin, have improved glycemic control, but most patients continue to spend significant periods outside of target blood glucose ranges. Even with the current best treatments and careful glucose control, patients with T1D live an estimated decade shorter than those without the disease. All current therapies require patients to carefully monitor their dietary intake, which, although inconvenient in adults, is a frequent point of failure in adolescents and children.

Pancreas transplantation for uncontrollable diabetes was first performed in the 1960s and established the principle that replacing the pancreatic 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 medical 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 iPSC-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) using our hypoimmune technology to genetically modify iPSCs to evade allogeneic immune responses, (ii) using our hypoimmune technology to genetically modify iPSCs to evade autoimmune destruction of islet cells, and (iii) deriving highly functional islet cells from these genetically-modified iPSCs. 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 iPSCs has the potential to solve limitations associated with use of a donor pancreas and improve the overall product quality and product consistency. iPSCs have the potential to create a virtually limitless supply of these cells. We apply our hypoimmune technology to modify the genomes of the iPSCs. We believe the hypoimmune genome modifications have the potential to protect these PSC-derived islet cells from both allogeneic and autoimmune 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. After modifying the PSC genome, our program uses proprietary differentiation protocols to generate mature islet cells with in vivo glucose control comparable to primary human islets, as evidenced by our animal studies.

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Preclinical Data

Building upon exclusively licensed intellectual property, we are further developing a proprietary protocol to differentiate hypoimmune iPSCs into mature, glucose-sensitive, insulin-secreting islet cells. We are exploring ways to optimize the differentiation of islet cells at a greater purity with superior function and a greater scale compared to published stem cell-based protocols. The principal function of pancreatic beta cells, the insulin-secreting cells within an islet, is to maintain steady levels of glucose in circulation and drive glucose uptake into cells throughout the body. The pancreatic beta cells sense when glucose levels rise in the bloodstream and release insulin in response. We have observed that our iPSC-derived islet populations can respond to glucose and secrete insulin in vitro and in vivo.

These iPSC-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 without any evidence of abnormal cell growths or other safety signals.

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 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 autologous pancreatic islets. 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 mouse's 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 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.

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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.

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HIP-Modified iPSC-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 iPSC-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 iPSC Islets In Vivo at 51 Weeks Post-Transplant. HIP-modified iPSC 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 iPSC Islets. Graph demonstrates the persistent efficacy of HIP-modified iPSC islet cells in controlling blood glucose levels for greater than 64 weeks. Nonfasted blood glucose levels were measured following transplantation of iPSC-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 iPSC-derived islet cells (n=2). Data is presented as mean ± S.E.M.

We are developing SC451, our HIP-modified iPSC-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 iPSC-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 iPSCs in the final product. In vitro studies indicate that HIP modification of iPSC-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 iPSC 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.

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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. We subsequently shared updated data at twelve weeks, 26 weeks, and 52 weeks post-transplant, which show ongoing survival, function, and immune evasion of these transplanted beta cells. 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 a MMTT, which measures the ability of pancreatic beta cells to respond to a glucose bolus in the blood. 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, twelve, 26, 38, and 52 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. PET/MRI scans at twelve weeks and 52 weeks post-transplant demonstrate uptake of a radiotracer consistent with pancreatic beta cells in the forearm muscle of the patient, a result consistent with ongoing graft survival. No inflammation or safety-related signals were observed. The twelve-week data were published in The New England Journal of Medicine in September 2025.

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. The investigator ran in vitro assays exploring whether the patient’s immune system, either specific cell types or in whole, recognized and killed these various cell populations from the drug product. WT islet cells triggered a robust immune response, with peak T cell activation at day seven 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 52 weeks. These distinct immune responses were further validated in whole blood assays, where HIP islet cells 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 results with HIP-modified cells represent a significant milestone for the field of cell therapy. These cells not only had to overcome the typical rejection of allogeneic cells, they also needed to overcome the pre-existing autoimmune response to pancreatic beta cells. 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.

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 seven following UP421 transplantation and present to week 52, indicating survival of UP421 cells.

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

Prior to UP421 transplantation, C-peptide was below the limit of detection during MMTT (grey line). At multiple measurement dates from weeks 4-52 post-transplantation, C-peptide is detectable and increases with MMTT stimulation, supporting ongoing survival and function of UP421 cells.

PET/MRI Imaging Shows Localization of UP421 Graft and Uptake of GLP‑1R-Specific Tracer, Week 12 and Week 52

PET/MRI images of the forearm following intramuscular administration of UP421. MR T2‑STIR‑weighted imaging demonstrates localized signal within the musculus brachioradialis at the injection site, consistent with visualization of the transplanted cell graft. PET/MRI imaging shows uptake of an Exendin‑4–based tracer specific for glucagon‑like peptide‑1 receptor (GLP‑1R)-positive cells at the same location, consistent with pancreatic beta cell survival in the forearm.

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Unmodified Islet Cells Do Not Evade Immune Responses

In vitro assay testing exposure of patient blood drawn over time to wild-type, or unmodified, cells from UP421. There is no baseline immune response to these unmodified cells, but one rapidly develops within days (data not shown above) and is maintained over twelve months, with both a T cell and antibody response to these cells (data not shown).

dKO Islet Cells are Killed by NK Cells

In vitro assay testing exposure of patient blood drawn over time to the cell population within UP421 with successful knock-out of MHC class I and MHC class II, but no overexpression of CD47. There is a baseline immune response and killing of these cells, which is maintained over 52 weeks, which is mediated by NK cells (data not shown).

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

In vitro assay testing exposure of patient blood drawn over time to the cell population within UP421 with successful incorporation of all of the HIP modifications. There is no baseline immune response to these cells, and no immune response develops over the course of 52 weeks.

Next Steps

We are transferring our manufacturing process to GMP facilities and completing our preclinical testing of SC451. We expect to submit an IND and begin our Phase 1 clinical trial for SC451 as early as this year.

Our in vivo Cell Engineering Platform

Overview

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

Our in vivo cell engineering platform is focused on engineering fusogens that, when combined with delivery vehicles, can effectively deliver a payload to a desired cell or location in the appropriate quantities in vivo. 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 for in vivo therapies.

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Our Approach to Building Our in vivo Cell Engineering Platform

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

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Delivery. We believe the critical limitation for in 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 performed in 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 our in 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 that in 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 of in vivo cell engineering's potential, with success limited to a small number of patients. The broader impact of in 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 cells 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 central nervous system 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.

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

Background on Fusogens

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

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Our Fusogen Technology

Fusogens are widely used by enveloped viruses to confer target specificity and to drive the process of introducing material in target cells. A well-known current example of a viral fusogen is 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 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 modular system that can specifically target numerous cell surface receptors and thereby deliver diverse therapeutic payloads to a variety of cell types.

Our current program uses fusogens derived from several viruses from the paramyxoviridae family. The fusogen protein complexes in this family are 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. This mechanism allows for endosome-independent delivery of the payload, a key differentiating factor versus many other systems, described in more detail below.

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

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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 payload in 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 focus 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.

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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 seven 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.

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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 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 payloads in vivo has the potential to create autologous, gene-modified cells without the complexities of ex vivo manufacturing. We believe that these therapies have the potential to have greater product consistency, improved scale, and lower costs than current autologous solutions. Currently, there are a number of therapies either approved or in development for ex vivo modification of autologous and allogeneic T cells. Additionally, vectors that deliver payloads to random or off-target cells not only create the risk for toxicities and immunogenicity, but they need 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. We are also investing across a number of areas to improve manufacturing scale, costs, consistency, and product quality in the near- and long-term.

Our in vivo Cell Engineering Pipeline

T Cell Fusosome Program (SG293)

Our most advanced CAR T cell fusosome product candidate is SG293, a CD8-targeted fusosome that delivers a CD19-directed CAR to target CD19+ cells that we are developing to treat patients with hematologic malignancies and autoimmune diseases.

Background on B Cell Malignancies

Non-Hodgkin lymphoma (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.

Acute lymphoblastic leukemia (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 relapsed or remitting, or 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.

Current Treatment Landscape and Unmet Need

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 autologous CAR T therapies tisagenlecleucel, axicabtagene ciloleucel and lisocabtagene maraleucel; CD20xCD3 bi-specific antibodies epcoritamab-bysp and glofitamab-gxbm; CD19 antibody drug conjugate therapy polatuzumab vedotin; and CD19 antibody tafasitamab. Two of these 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.

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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 tisagenlecleucel 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,

T Cell-Targeted Fusosome Approach

We believe that our T cell-targeted fusosome approach provides us with an opportunity to develop CAR T cell therapies that can be more broadly accessible to patients than currently available treatments. 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 and safety over ex vivo manufactured CAR T cell products. 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 and ex vivo manufacturing. 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 an in 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 of ex vivo manufactured CAR T cells is dependent on the administration of a lymphodepleting preparative regimen prior to infusion to facilitate expansion of the CAR T cell product, which can have meaningful adverse safety implications. We do not expect to use a lymphodepleting regimen pre-exposure to in vivo delivery of the CAR gene.

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 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 proteins in vitro.

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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.

A prior candidate from our fusogen platform, SG299, a CD8-targeting fusogen that cross reacts with CD8 in most NHP species, included a CD19 CAR gene that encoded for a CD19-targeted CAR that does not cross-react with NHP CD19. In a GLP toxicology study conducted in nemestrina 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 was 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. Because the CD19 CAR does not cross-react with nemestrina CD19, we were unable to explore CAR T expansion kinetics or efficacy in depleting target cells in this experiment.

To evaluate in vivo CAR T generation and B cell depletion, we developed a surrogate SG299 that delivers a CD20 CAR capable of targeting NHP B cells in cynomolgus 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.

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Taken together, these results suggested that SG299 could be safely dosed in NHPs and had the potential to deliver a CAR transgene that could 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.

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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.

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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.

SG293

We next incorporated the findings from these as well as several other studies into our next-generation product, SG293, which has several important changes when compared to SG299 while retaining the CD19 CAR. First, SG293 utilizes a fusogen from a different paramyxovirus, which in preclinical models has demonstrated enhanced potency and specificity. Second, SG293 incorporates an activation signal on the surface of the fusosome to enhance CAR expression and early potency post-transduction. Third, we have made several changes to the manufacturing process to minimize the expression of the CAR transgene on the fusosome surface, which we have shown in animal models decreases the risk of an immune response to the CAR, as well as improve safety. We believe these changes will enhance efficacy, safety, and manufacturability.

In January 2026, we shared data from a preclinical study using a surrogate for SG293 that delivers a CD20 CAR capable of targeting NHP B cells in cynomolgus macaques. No lymphodepletion was administered to the NHPs in this study. A single intravenous injection of SG293 to these NHP resulted in robust in vivo generation of CAR T cells and deep B cell depletion in the peripheral blood and lymph nodes. The B cell depletion was further confirmed by lymph node biopsies showing clearing of B cells as well as by a “reset” of the NHPs’ B cell repertoire toward naïve B cells. We believe that deep B cell depletion in this preclinical model is the most significant biomarker for potential efficacy in patients with B cell cancers and B cell-mediated autoimmune diseases. Separately, in vitro studies using SG293 have shown selective gene delivery to CD8+ T cells with minimal or undetectable off-target transduction in tissues such as the liver and gonadal tissue, supporting the specificity of SG293. We continue to evaluate SG293 in other preclinical studies.

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Surrogate SG293 NHP Study Design

Surrogate SG293 Transduces CD8+ T Cells in NHPs with Expansion over 7-28 Days

Surrogate SG293 Results in Deep B Cell Depletion in Peripheral Blood in NHPs

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Surrogate SG293 Results in Deep B Cell Depletion in NHP Lymph Node

B cell clearance in lymph nodes without lymphodepletion. Lymph nodes from cynomolgus macaques injected intravenously with an SG293 surrogate delivering a CD20 CAR transgene. Biopsy performed three-weeks post-injection in one control animal and two treated animals. Tissues were analyzed by immunohistochemistry. Brown, anti-CD20; blue, hematoxylin; black, tattoo ink.

Surrogate SG293 Results in B Cell “Reset” in NHPs

B cell reset in nonhuman primates (NHPs) is illustrated by the depletion of circulating and lymphoid tissue B cells following a single intravenous administration of an SG293 surrogate, followed by repopulation of the B cell compartment with a predominance of naïve B cells. In these studies, B cell reconstitution was characterized by an increased proportion of IgD⁺/CD27⁻ naïve B cells relative to memory B cell subsets, consistent with a resetting of the B cell repertoire.

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SG293 Demonstrates Greater in vitro Specificity for On‑Target Cells Compared to a Targeted VSV‑G Fusogen

In vitro assessment of fusogen‑mediated gene delivery across on‑target and off‑target cell types. Shown is vector copy number (VCN) per diploid genome following exposure of indicated human cell lines and primary cells to SG293, SG299, or a blinded VSV‑G fusogen control. On‑target cells represent CD8⁺ T‑cell surrogates, while off‑target cells include cell lines and primary cells with low or high phagocytic activity, endothelial cells, epithelial cells, hepatocytes, and CD34⁺ hematopoietic progenitor cells under resting and activated conditions. Data illustrate selective gene delivery by SG293 to on‑target cells with lower relative transduction of off‑target cell types compared to the targeted VSV‑G fusogen under the tested conditions.

Development Plan and Key Next Steps

We intend to develop SG293 initially in B cell cancers such as non-Hodgkin lymphoma and acute lymphoblastic leukemia. If we generate appropriate safety and efficacy signals in these settings, we intend to expand testing into B cell mediated autoimmune diseases such as lupus. We are also developing in vivo CAR T therapies toward other targets, such as B cell maturation antigen ( BCMA), though we plan to learn from initial clinical experience with SG293 before advancing therapies for other targets into human testing. We intend to begin clinical testing and generate initial clinical data for SG293 as early as this year.

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 in 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 access to these innovative engineered cells as medicines. Two areas of particular focus are product analytical and biological characterization, leading to a better definition of critical product attributes, as well as process understanding, leading to better control the impact of process parameters on these critical product attributes.

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

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establishing a team with diverse experience and talent 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 manufacturing platforms for our ex vivo and in vivo product candidates; and

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

To support our development activities, we have established process development for our iPSC-derived and fusogen platform 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 key areas in our iPSC-derived therapy processes to enable scaled manufacturing. 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.

Competition

Other companies have stated that they are developing cell and gene therapies that may address type 1 diabetes, oncology, and B cell mediated autoimmune disorders. 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 AbbVie Inc., Allogene Therapeutics, Inc., Aspect Biosystems Ltd., AstraZeneca PLC, Bristol-Myers Squibb Company, Cabaletta Bio, Inc., Caribou Biosciences, Inc., Century Therapeutics, Inc., CRISPR Therapeutics AG, Eli Lilly and Company, Gilead Sciences, Inc., Johnson & Johnson, Kelonia Therapeutics, Inc., Kyverna Therapeutics, Inc., Legend Biotech Corporation, Novartis AG, Roche Holding AG, Umoja Biopharma, Inc., and Vertex Pharmaceuticals Inc., might be conducting small- or large-scale clinical trials for therapies that could be competitive with our ex vivo and in vivo programs. Among companies pursuing ex vivo and in vivo cell engineering, we believe we are substantially differentiated by our robust intellectual property portfolio, extensive research, rigorous and objective approach, and multidisciplinary capabilities.

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 own numerous patents and patent applications, which include claims directed to compositions, methods of use, processes, dosing, and formulations, and possess substantial know-how and trade secrets relating to the development and commercialization of our ex vivo and in vivo cell engineering platforms and related product candidates, including related manufacturing processes. As of January 2026, our in-licensed and owned patent portfolio consisted of approximately 48 licensed or owned United States issued patents, approximately 57 licensed United States pending patent applications, and approximately 70 owned United States pending patent applications, as well as approximately 101 licensed patents issued in jurisdictions outside of the United States, approximately 234 licensed patent applications pending in jurisdictions outside of the United States, and approximately 238 owned patent applications pending in jurisdictions outside of the United States (including approximately 26 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.”

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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 due to 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 for our patents, 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. 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.

Our patents issued as of January 2026 have terms expected to expire on dates ranging from 2029 to 2042. If patents are issued on our patent applications pending as of January 2026, the resulting patents are projected to expire on dates ranging from 2033 to 2046. As discussed elsewhere in this Annual Report, we are currently prioritizing development of our SC451 program for the treatment of type 1 diabetes, which uses our hypoimmune technology, and our SG293 program for the treatment of B cell-mediated diseases, which uses our fusogen technology.

There are approximately four patent families containing granted patents that are currently material to our SC451 program, which are licensed to us. The first patent family includes patents granted in the United States and Australia, which include composition of matter, use, and process protection, and the last of which is currently expected to expire in 2036. The second patent family includes patents granted in Australia and New Zealand, which include composition of matter, use, and process protection, and the last of which is currently expected to expire in 2038. The third patent family includes patents granted in the United States and Israel, which include composition of matter and process protection, and the last of which is currently expected to expire in 2041. The fourth patent family includes patents granted in Australia and Japan, which include composition of matter, use, and process protection, and the last of which is currently expected to expire in 2039. Each of these patent families also includes pending patent applications in other jurisdictions.

There are approximately two patent families containing granted patents that are currently material to our SG293 program, which are licensed to us. The first patent family includes patents granted in the United States, Australia, Europe, Hong Kong, Israel, Japan, Korea, Mexico, and Singapore, which include composition of matter, use, and process protection, and the last of which is currently expected to expire in 2039. The second patent family includes patents granted in Australia, Japan, and Korea, which include composition of matter, use, and process protection, and the last of which is currently expected to expire in 2039. Each of these patent families also includes pending patent applications in other jurisdictions.

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 of 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.

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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. Further, any patents that we hold may be challenged, circumvented, or invalidated.

The area of patent and other intellectual property rights in biotechnology continues to evolve and has 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 allowable patent claims in the fields of cell and gene therapy has emerged in the United States. Companies' patent positions 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 ability to obtain and enforce patent claims that cover our technologies, inventions, and improvements. With respect to both our in-licensed and owned intellectual property, we cannot be sure that patents will be granted with respect to any pending patent applications or with respect to any patent applications we may file 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 prevent us from commercializing our patented product candidates and practicing our proprietary technology. It is uncertain whether the issuance of any patent to a third party 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 products may have a material adverse impact on us. If third parties 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 face competition for our product candidates. Moreover, because of the extensive time required for development, testing, and regulatory review of a potential product candidate, it is possible that, before any particular product candidate can be commercialized, any related patent may expire or remain in force for only a short period following commercialization, thereby reducing any advantage of the patent. Our commercial success will also depend in part on not infringing upon the proprietary rights of third parties. Patent disputes are sometimes interwoven into other business disputes.

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As of January 2026, our registered trademark portfolio contained approximately 25 registered trademarks and pending trademark applications, consisting of approximately three registered trademarks in the United States and approximately 21 registered trademarks and approximately one pending trademark application 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, advisors, or other third parties 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 additional information regarding this and more comprehensive risks related to our proprietary technology, inventions, improvements, and products, see the subsection titled “Risk Factors —Risks Related to Intellectual Property and Information Technology.”

Key Intellectual Property Agreements

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

Ex vivo Cell Engineering Platform

License Agreement with Harvard

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

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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, 2025, and 2026, 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 Harvard 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, 2025, 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, which we expect to occur in 2039, (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. 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 UCSF Agreement 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 rights under 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 our ex vivo cell engineering platform that relies on our hypoimmune technology.

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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. 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 annual license maintenance fees of $40,000 per year. 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 amount will be credited against any earned royalty due for the 12-month period for which the minimum payment was made and will be pro-rated under certain circumstances. 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, 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 License Agreement with Washington University

In November 2019, we entered into an exclusive 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).

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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 patent rights licensed to us under the 2019 WU Agreement. 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 agreed (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 our ex vivo cell engineering platform that relies on our hypoimmune technology, including our pancreatic islet cell program.

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.

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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 2039. 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 agreed (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.

License Agreement with FCDI

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

Pursuant to the FCDI Agreement, we agreed to pay FCDI an upfront fee of $1.0 million, annual license maintenance fees, and license fees of up to $500,000 per indication for one certain cell type or up to $350,000 per indication for certain other cell types. We are required to pay FCDI up to an aggregate of $28.5 million per indication upon the achievement of certain specified development and regulatory milestones for up to a total of three indications and up to an aggregate of $14.25 million in specified development and regulatory milestones for each additional indication. We are also required to pay up to an aggregate of $8.8 million per product upon the achievement of certain specified commercial milestones. In addition, we are obligated to pay royalties on worldwide annual net sales of the relevant products in the low- to mid-single digits, which obligation shall commence upon the first commercial sale of a relevant product and shall expire after 15 years on a product-by-product and country-by-country basis. The royalty rates are also subject to reduction upon certain other events.

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

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License Agreement with Beam

In October 2021, we entered into an option and license agreement (as amended, the Beam Agreement) with Beam Therapeutics, Inc. (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 allogeneic T cell products, or (ii) comprise certain human cell types, with respect to stem cell-derived products. 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 allogeneic T cell products, or human cell types, with respect to stem cell-derived products, in each case, upon our payment of an option payment of $10.0 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. Subject to certain limitations, (i) until the expiration of such option period, we had the right to elect to replace an antigen target, with respect to allogeneic T cell products, or human cell type, with respect to stem cell-derived products previously selected by us, and (ii) for a period of three years from the effective date of the Beam Agreement, we had the right to select new gene editing targets, or replace gene editing targets previously selected by us, with respect to any licensed product.

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, which we expect to occur in 2039, (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 allogeneic T cell licensed products), on a cell type-by-cell type basis (with respect to stem cell-derived licensed products), 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.

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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 (the Cobalt Merger 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 which 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, which we expect to occur in 2041, or (ii) the date on which the last applicable additional milestone payment has been made in accordance with the Cobalt Merger Agreement. 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' 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. 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.

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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 our in 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 which we expect to occur in 2039, or any patent term extension or supplementary protection certificate thereof covering the sale of such licensed product in such country. 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 if we undergo a cessation of business, dissolution or voluntary liquidation, or (ii) in full or in part (x) if we challenge the validity of the licensed patents, provided that such termination will be with respect to the claims within the licensed patents that are the subject of such challenge, or (y) if we fail to achieve the diligence milestones, and if the parties have not extended such milestones after good faith negotiations, and subject to our ability to cure such failure within 90 days after notice of the same.

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License Agreement with UCLA

In March 2019, we entered into a license agreement (as amended, the UCLA Agreement) with UCLA, pursuant to 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 our in 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 (iii) 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. 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.

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The UCLA Agreement will expire on the later of the expiration of the last-to-expire patent in the licensed patent rights, which we expect to occur in 2033, or the last to be abandoned patent application in the licensed patent rights. 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.

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 certain in vivo gene therapy and ex vivo allogeneic CAR T cell applications for B cell malignancies. The license grant is subject to customary statutory requirements and reserved rights as required under federal law and NIH requirements. We have the right to grant sublicenses under the licensed patent rights with the NIH’s prior consent.

Pursuant to the NIH Agreement, we paid to the NIH an upfront payment of $1.0 million. Additionally, we will be obligated to pay to the NIH (i) up to an aggregate of $9.6 million in specified regulatory, developmental, and commercial milestone payments 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 (a) 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 (b) 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 (x) $5.0 million or (y) 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, which we expect to occur in 2041. 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.

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.

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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 and in vitro studies assessing the toxicology, pharmacokinetics, pharmacology, and pharmacodynamic characteristics of the product; chemistry, manufacturing, and controls information; and any available human data or literature to support the use of the investigational product. An IND must become effective before human clinical trials may begin. The IND automatically becomes effective 30 days after receipt by the FDA, unless the FDA, within the 30-day time period, raises safety concerns or questions about the proposed clinical trial. In such a case, the IND may be placed on clinical hold and the IND sponsor and the FDA must resolve any outstanding concerns or questions before the clinical trial can begin. Submission of an IND therefore may or may not result in FDA authorization to begin a clinical trial.

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.

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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 or in 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.

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Within 60 days following submission of the application, the FDA reviews a BLA submitted to determine if it is substantially complete before the FDA accepts it for filing. The FDA may refuse to file any BLA that it deems incomplete or not properly reviewable at the time of submission and may request additional information. In this event, the BLA must be resubmitted with the additional information. Once a BLA has been accepted for filing, the FDA’s goal is to review standard applications within ten months after the filing date, or, if the application qualifies for priority review, six months after the FDA accepts the application for filing. In both standard and priority reviews, the review process may also be extended by FDA requests for additional information or clarification. The FDA reviews a BLA 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. The FDA’s decision to release in “real-time” newly issued CRLs associated with withdrawn or abandoned applications, if applicable to any of our product candidates, could materially impact our business and competitive advantage.

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.

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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, including priority review, fast track, breakthrough therapy, accelerated approval, and national priority voucher programs, although the FDA’s policies and implementation of these and similar programs are subject to change. 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.

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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.

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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.

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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 Management System Regulation (QMSR), which went into effect in February 2026, replaces the former Quality System Regulation, imposes testing, control, documentation, and other quality assurance requirements, and incorporates by reference the quality management system requirements of ISO 13485:2016.

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.

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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.

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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.

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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. Further, the current administration has issued executive orders focused on decreasing prescription drug prices, including directing the Secretary of HHS to establish a mechanism through which American patients can buy drugs directly from manufacturers who sell at a most-favored-nation price and directing the United States Trade Representative and Secretary of Commerce to take action to ensure foreign countries are not engaged in practices that purposefully and unfairly undercut market prices and drive price hikes in the United States. In November 2025, CMS announced a voluntary initiative called the GENEROUS Model (GENErating cost Reductions fOr U.S. Medicaid Model) to introduce the option of most-favored-nation pricing to the Medicaid program, whereby a drug manufacturer may voluntarily offer supplemental rebates to participating state Medicaid programs for a manufacturer’s covered outpatient drugs. Government agreements with pharmaceutical companies and other measures that use most-favored-nation pricing targets for prescription drugs or that increase generic and biosimilar drug entry sooner than expected could have a material adverse effect on our industry, ability to set adequate pricing for new drugs to recover research and development costs, ability to attract potential investors and potential buyers in the future, or the pricing of our approved product in the United States and in foreign countries. The impact of these and any future healthcare measures, executive orders, and agency rules implemented by the current 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.

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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, which provides a single-entry point for sponsors and regulators of clinical trials for the submission and assessment of clinical trial data. 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, 2025, we had 142 employees, 104 of whom were primarily engaged in research and development activities. A total of 83 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 and bonus 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.

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 350, Seattle, Washington 98102, and our telephone number is (206) 701-7914. Our website address is www.sana.com. The information on, or that can be accessed through, our website is not part of this 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 is www.sec.gov.

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