Scholar Rock Holding Corp

I.** Overview**

We are a late-stage biopharmaceutical company focused on the discovery, development and delivery of innovative medicines for the treatment of serious diseases in which signaling by protein growth factors plays a fundamental role. As a global leader in transforming growth factor beta (“TGFβ”) superfamily biology, our novel understanding of the molecular mechanisms of growth factor activation enabled us to develop a proprietary platform for the discovery and development of monoclonal antibodies that locally and selectively target the precursor, or latent, forms of growth factors. By targeting the signaling proteins at the cellular level and acting in the disease microenvironment, we believe we may avoid the historical dose-limiting safety challenges associated with inhibiting growth factors for therapeutic effect. We believe our focus on biologically validated growth factors may facilitate a more efficient development path.

Based on this proprietary and scalable technology platform, we are building a growing portfolio of novel product candidates with the aim of transforming the lives of patients suffering from a wide range of serious diseases, including neuromuscular disorders, cardiometabolic disorders, cancer, fibrosis and iron-restricted anemia. We have discovered and progressed the development of:

Our first product candidate, apitegromab, is a highly selective, fully human, monoclonal antibody, with a unique mechanism of action that results in inhibition of the activation of the growth factor, myostatin, in skeletal muscle. Apitegromab is being developed as a potential first muscle-targeted therapy for the treatment of SMA. We completed SAPPHIRE, a pivotal Phase 3 clinical trial to evaluate the efficacy and safety of apitegromab in patients with nonambulatory Type 2 and Type 3 SMA (which is estimated to represent the majority of the current prevalent SMA patient population in the U.S. and Europe)and announced positive top-line results in October 2024. The study achieved its primary endpoint (see “Phase 3 SAPPHIRE Pivotal Trial” below). We submitted a U.S. Biologics License Application (“BLA”) to the FDA in January 2025 and are planning to submit a European Union marketing authorization application to the European Medicines Agency (“EMA”) in the first quarter of 2025. If apitegromab is approved, we

expect to initiate a commercial product launch in the fourth quarter of 2025 in the United States, with a commercial launch of apitegromab in Europe to follow.

Apitegromab was evaluated in our Phase 2 TOPAZ proof-of-concept clinical trial for the treatment of patients with Type 2 and Type 3 SMA. Positive 12-month top-line results were initially announced in April 2021. We have subsequently presented data from the TOPAZ trial over 24-months (2022), 36-months (2023) and 48-months (2024). At 48-months over 90% of TOPAZ patients with nonambulatory Type 2 and 3 SMA receiving a survival motor neuron (“SMN”) therapy remained on apitegromab treatment and showed sustained clinical benefit, a continued favorable safety profile with no new safety findings (see “Phase 2 TOPAZ Proof-of-Concept Trial” below). Additionally, we are conducting a long-term extension study, ONYX, for patients from both the TOPAZ and SAPPHIRE studies, who were receiving apitegromab in conjunction with an approved SMN therapy. The FDA granted Fast Track designation, Rare Pediatric Disease designation and Orphan Drug designation to apitegromab for the treatment of SMA in May 2021, August 2020 and March 2018, respectively. The EMA granted Priority Medicines (“PRIME”) designation in March 2021 and the EC granted orphan medicinal product designation in December 2018 to apitegromab for the treatment of SMA.

In October 2023, we announced an expansion of our therapeutic focus into cardiometabolic disorders by advancing our anti-myostatin program with SRK-439, a novel, fully human anti-myostatin monoclonal antibody, for evaluation in cardiometabolic disorders, including obesity. We are developing SRK-439 towards a potential investigational new drug application (“IND”) submission in the third quarter of 2025. In 2024, we presented preclinical data at scientific conferences which support the potential of SRK-439 to increase lean mass and contribute to a favorable body composition in conjunction with a GLP-1 receptor agonist (“GLP-1 RA”) treatment. To inform the development of SRK-439, in May 2024 we initiated the Phase 2 EMBRAZE proof-of-concept trial, designed to assess the safety and efficacy of apitegromab to preserve muscle mass in individuals living with obesity and on background therapy of a GLP-1 RA. In September 2024, we announced that we completed enrollment in the Phase 2 EMRAZE proof-of-concept trial. Top-line results from this trial are expected in the second quarter of 2025.

We believe that apitegromab has the potential to be the first muscle-targeted therapy that is aimed at improving motor function in patients with SMA who are receiving an SMN therapy. We have identified multiple other diseases for which the selective inhibition of the activation of myostatin may offer therapeutic benefit, including additional patient populations in SMA (such as patients with SMA under 2 years of age) and indications for other neuromuscular disorders beyond SMA.

Our second product candidate, SRK-181, a highly selective inhibitor of the activation of latent TGFβ1, is being developed for the treatment of cancers that are resistant to checkpoint inhibitor therapies (“CPI therapies”), such as anti-PD-1 or anti-PD-L1 antibody therapies (referred to together as anti-PD-(L)1 antibody therapies). SRK-181 is being evaluated in our Phase 1 DRAGON proof-of-concept clinical trial in patients with locally advanced or metastatic solid tumors that exhibit resistance to anti-PD-(L)1 antibody therapies. We completed enrollment of the DRAGON trial in December 2023 and continue to treat patients who remain on study. This two-part clinical trial consists of a dose escalation portion (Part A) and a dose expansion portion evaluating SRK-181 in combination with an approved anti-PD-(L)1 antibody therapy (Part B). Part B commenced in 2021 and includes the following active cohorts: urothelial carcinoma, cutaneous melanoma, non-small cell lung cancer, clear cell renal cell carcinoma (“ccRCC”) and head and neck squamous cell carcinoma (“HNSCC”). Safety, efficacy and biomarker data were presented in June 2024 at the American Society of Clinical Oncology (“ASCO”) annual meeting and in November 2024 at the Society for Immunotherapy of Cancer (“SITC”) 39 th Annual Meeting. The data showed encouraging responses in heavily pretreated and anti-PD-(L)1 resistant patients across multiple tumor types. We believe that the DRAGON trial achieved its study objectives by showing objective, durable clinical responses in patients with ccRCC resistant to PD-1 therapy above what is expected from continuing PD-1 alone. We anticipate that emerging data from the DRAGON trial will be presented at medical meetings in the future.

Beyond these programs, we continue to discover and develop highly specific monoclonal antibodies to selectively modulate growth factor signaling. Growth factors are naturally occurring proteins that typically act as signaling molecules between cells and play a fundamental role in regulating a variety of normal cellular processes, including cell growth and differentiation. Current therapeutic approaches to treating diseases in which growth factors play a fundamental role involve directly targeting the active form of the growth factor or its receptor systemically throughout

the body. These approaches have suffered from a variety of shortcomings, including lack of pathway selectivity, lack of target selectivity, and non-localized target inhibition.

Our innovative approach is rooted in our structural biology insights into the mechanism by which certain growth factors are activated in close proximity to the cell surface. We integrate these insights with sophisticated protein expression, monoclonal antibody discovery capabilities, and assay development to test the characteristics of our monoclonal antibodies. We believe our proprietary platform can address the challenges of treating diseases in which growth factors play a fundamental role by:

Our structural insights and unique antibody discovery capabilities can be applied to other protein classes beyond growth factors, with an aim of generating differentiated candidates targeting cell surface receptors such as immune cell receptors or G-protein coupled receptors, where selectivity remains challenging.

II.Our Approach and Proprietary Platform

Our innovative approach is rooted in our novel understanding of the molecular mechanisms of growth factor activation and signaling and is designed to discover and develop monoclonal antibody product candidates that can inhibit the activation of a growth factor with an unprecedented degree of selectivity. Our proprietary platform is designed to generate highly selective antibodies that target the growth factor’s latent precursor form prior to its activation within the disease microenvironment, or tissue where it is localized.

Growth factors are naturally occurring proteins that typically act as signaling molecules between cells and play a fundamental role in regulating a variety of normal cellular processes. Members of the TGFβ superfamily of growth factors, for example, can mediate diverse biological functions, including cell growth and differentiation, tissue homeostasis, immune modulation and extracellular matrix remodeling. Growth factors have also been shown to play a fundamental role in a variety of disease processes. Because of the importance of growth factors in multiple diseases, the pharmaceutical industry has made many attempts to inhibit growth factors in a variety of therapeutic settings. However, products utilizing conventional approaches have seen only limited success. Current therapeutic approaches to treating diseases in which growth factors play a fundamental role involve directly targeting an activated growth factor or its receptor systemically throughout the body and have suffered from a variety of shortcomings:

Our approach to the discovery and development of growth factor targeted drugs is new and different from traditional approaches. Our approach of targeting the precursor, or latent forms of growth factors is based on the breakthrough discovery by the laboratory of our cofounder, Timothy A. Springer, Ph.D. of Harvard Medical School and Boston Children’s Hospital.

Unlike many other proteins that are produced and secreted by cells in a mature, or active, form, many growth factors are expressed by cells in a latent form. For example, TGFβ1 is produced by cells as a single protein which is then enzymatically processed by the cells into two distinct and physically separated domains — the mature growth factor and the remaining portion of the original protein, referred to as the prodomain — which remain associated as part of a complex. This secreted complex is latent, or inactive, and must first be activated to carry out its normal function in a highly localized tissue or disease microenvironment. In a seminal peer-reviewed publication in 2011, Dr. Springer elucidated a new understanding of the mechanism of activation of the latent growth factor complex among members of the TGFβ superfamily by solving a high-resolution x-ray crystal structure of this latent form of TGFβ1 (as illustrated in the graphic below).

Structural representation of the latent form of TGFβ 1 wherein the prodomain wraps around the active growth factor

This research explained at a molecular level why the secreted form of TGFβ1 is inactive. The prodomain, though physically separated from the mature growth factor domain, forms a “cage” around the active form of TGFβ1, blocking the growth factor from signaling through its receptor. Only when the cage is “unlocked” by a precursor activation event can the growth factor be released and mediate its effects in the local microenvironment. Dr. Springer further hypothesized that this phenomenon likely holds true for most members of the TGFβ superfamily, though the exact nature of the activation event, such as integrin binding or enzymatic cleavage, may differ among members of the superfamily. Importantly, while many growth factors are structurally very similar, their cages are structurally diverse, and this provides the basis for our approach to improved selectivity.

We believe that there are several important advantages to our approach of targeting the precursor, or latent, forms of growth factors over conventional therapeutic approaches, which inhibit mature growth factors or their receptors systemically throughout the body:

activation is a preferred mode of action for achieving improved outcomes. In contrast, traditional approaches to targeting growth factor signaling are focused on inhibiting the growth factor after it has been activated and released systemically;

To enable our novel approach, we have built a proprietary platform that is rooted in our structural biology insights into activation of latent growth factor precursors. We integrate these insights with sophisticated protein expression, monoclonal antibody discovery capabilities, and assay development to test the characteristics of our monoclonal antibodies. In addition to this know-how, our proprietary platform is covered by patents projected to expire well into the 2030s, excluding any patent term adjustments or extensions. The key elements of our proprietary platform include the following:

Using our innovative approach and proprietary platform, we are creating a pipeline of novel product candidates that selectively modulate the activation of growth factors implicated in a variety of serious diseases. Our structural insights and unique antibody discovery capabilities can also be applied to other protein classes beyond growth factors, with an aim of generating differentiated candidates targeting cell surface receptors such as immune cell receptors or G-protein coupled receptors, where selectivity remains challenging.

III.Our Expertise

We have assembled an experienced management team, board of directors, and scientific founders who bring extensive industry experience to our company. The members of our team have deep experience in discovering, developing and commercializing therapeutics, having worked at companies such as: Acceleron Pharma, Inc.; Alnylam Pharmaceuticals,

Inc.; AMAG Pharmaceuticals, Inc.; Celgene Corporation; Foundation Medicine, Inc.; and Novartis Pharmaceuticals. We were founded by internationally respected scientists, Drs. Timothy A. Springer and Leonard I. Zon of Harvard Medical School and Boston Children’s Hospital.

IV.Our Strategy

Using our proprietary platform to unlock the therapeutic potential of targeting growth factor signaling in the disease microenvironment, our goal is to deliver novel therapies to underserved patients suffering from a wide range of serious diseases, including neuromuscular disorders, cardiometabolic disorders, cancer, fibrosis and iron-restricted anemia. To achieve this goal, we plan to:

protein growth factors in numerous diseases, we believe that these efforts could result in new opportunities to treat diseases with unmet medical need. In order to support our pipeline expansion and intention to be the leader in the field of growth factor-targeted drug development, we are investing in the technologies supporting our proprietary platform. We have designed a proprietary, state of the art, antibody display library to more efficiently identify differentiated candidate antibodies. Furthermore, we believe that our structural insights have applicability beyond growth factor activation to include other cell signaling mechanisms.

We believe that additional product candidates in the TGFβ portfolio have the potential to address other disorders associated with increased TGFβ signaling, including tissue and organ fibrosis. To advance the discovery and development of selected inhibitors originating from our TGFβ program that we believe have the potential to address unmet medical needs in non-oncology indications, we entered into a three-year fibrosis-focused collaboration with Gilead Sciences, Inc. (“Gilead”) in 2018. At the conclusion of the agreement in January 2022, the rights to the respective antibodies reverted to us. We have identified a suite of anti-fibrotic antibodies with novel selectivity profiles that were discovered over the course of the collaboration including those which may have therapeutic potential for the treatment of organ fibrosis by inhibiting TGFβ1 function in connective tissue while having no impact on the activation or signaling of TGFβ1 in the immune system. We plan to continue the advancement of these assets as part of our growing preclinical pipeline.

In addition, using our structural insight, we have identified modulators of BMP6 (a TGFβ superfamily growth factor) by selectively inhibiting its co-receptor RGMc or hemojuvelin which is required for activation. BMP6 functions as a critical control point in iron modulation via regulation of hepcidin. Traditional approaches to inhibiting the signaling of BMP6 systemically would likely perturb the numerous different physiological processes in which BMP6 is involved. Our approach could provide the potential for tissue specific modulation of BMP signaling and iron regulation.

V.Our Pipeline

Using our innovative approach and proprietary platform, we are creating a differentiated pipeline of novel product candidates that selectively inhibit the activation of latent growth factors believed to be important drivers in a variety of diseases, including neuromuscular disorders, cardiometabolic disorders, cancer, fibrosis, and iron-restricted anemia. Our proprietary platform includes (i) our know-how enabling expression and purification of latent protein growth factor complexes in quantity and quality sufficient to enable antibody discovery; (ii) strategies to identify rare antibodies that selectively bind targeted latent protein growth factor complexes; and (iii) assays developed by us to test the highly selective antibodies’ ability to modulate the activation of specific latent growth factors. We have worldwide rights to our proprietary platform and all of our product candidates.

The following summarizes our pipeline programs:

VI.Our Product Candidates

Utilizing our proprietary platform, we targeted the precursor form of myostatin and generated two novel antibodies, each with a design tailored for specific patient populations: apitegromab for SMA and SRK-439 for obesity. Both antibodies are novel, highly selective inhibitors of the activation of myostatin from its inactive precursor in skeletal muscle, where myostatin resides and signals upon activation. While mature myostatin is 90% identical in the growth factor domain to its most closely related TGFβ superfamily member, GDF11, the prodomain that cages mature myostatin and keeps it in its latent precursor form is only 52% identical to the GDF11 prodomain.

In preclinical studies, we have shown that apitegromab selectively avoids interaction with other closely related growth factors that play distinct physiological roles. We observed multi-fold increases in serum latent myostatin levels in mouse models of both early and late SMN restoration and that apitegromab promoted increased strength (as measured by torque generation) in SMN-deficient mice. In a Phase 1 clinical trial designed to evaluate the safety, tolerability, and pharmacokinetic (“PK”) /pharmacodynamic (“PD”) profile of apitegromab in adult healthy volunteers, there were no dose-limiting toxicities and we observed robust and sustained target engagement following administration of apitegromab.

SRK-439 has also shown robust preclinical efficacy, as detailed in “Cardiometabolic Disorders – SRK-439 (inhibitor of latent myostatin)” section below. We believe that these results, from two diet-induced obesity (“DIO”) mice models provide the scientific rationale and support the hypothesis that inhibition of myostatin in combination with GLP-1 RA-driven weight loss may lead to retention of lean muscle.

i. Role of Myostatin

Myostatin, also known as growth differentiation factor 8 (“GDF8”), is a member of the TGFβ superfamily and is produced by skeletal muscle cells. As with other tissues and organs in the human body, healthy muscle homeostasis is maintained by a proper balance of growth signals, or anabolic stimuli, and breakdown signals, or catabolic stimuli. In humans, the anabolic stimuli that drive muscle growth are proteins, such as the human growth hormone and the insulin

like growth factor 1. In contrast, myostatin is a catabolic agent that functions as a negative regulator of muscle mass. Animals lacking functional myostatin genes, or its receptor, have larger muscles and increased strength compared to normal animals. Such animals are otherwise healthy and live a normal lifespan.

ii. Traditional Approaches and Challenges

Because of its role in regulating muscle mass, myostatin has been a popular target for a variety of drug development programs. There have been two general approaches to trying to inhibit the signaling of myostatin in humans. The first is to develop an antibody, or an antibody-like molecule, that binds to mature myostatin in circulation and prevents its ability to signal through its receptor, the ActRIIb receptor. The second is to develop an antibody to the ActRIIb receptor itself, or a soluble decoy of the ActRIIb receptor, with a goal of preventing myostatin signaling through its receptor. Both of these approaches, however, have significant limitations.

As a member of the TGFβ superfamily, mature myostatin shares considerable structural similarity with other family members. For example, the active form of myostatin and its most closely related family member, GDF11, are 90% identical in the growth factor domains, making it extremely challenging to identify antibodies that are truly specific for myostatin and do not interfere with other targets. Moreover, attempts to interrupt myostatin signaling through its receptor are complicated by the fact that the ActRIIb receptor, in addition to being the receptor for myostatin, is also the receptor for a number of related family members, including GDF11, activins and other growth factors. Attempts to block the signaling of myostatin by targeting its receptor therefore inevitably interfere with the signaling of these other growth factors, many of which are involved in normal biological processes unrelated to muscle.

There are multiple examples of clinical trials demonstrating the risk of non-selective inhibition of myostatin. For example, in a Phase 2 clinical trial in Duchenne Muscular Dystrophy reported in 2017, a soluble decoy of the ActRIIb receptor resulted in bleeding side effects believed by the sponsor to be unrelated to inhibition of myostatin signaling, but instead related to the inhibition of signaling by certain other members of the TGFβ superfamily known to be important in the maintenance of vascular integrity. These side effects resulted in termination of the clinical program. More recently, results from a clinical trial were reported showing that treatment of patients with an antibody to the ActRIIb receptor resulted in suppression of the levels of follicle stimulating hormone, an important reproductive hormone. In this clinical trial, the sponsor believed that these effects were likely related to inhibition of signaling through the ActRIIb receptor.

iii. Spinal Muscular Atrophy: Apitegromab (inhibitor of latent myostatin activation)

We believe that the therapeutic potential for apitegromab in improving motor function is more optimal when a given disease bears certain features, including neuromuscular disorders with muscle atrophy as a key component of disease pathogenesis, presence of intact or partially intact muscle innervations, absence of significant muscle structural abnormalities, and where validated clinical outcome measures are available to assess muscle function in a clinical trial. SMA is a genetic disorder with onset commonly in childhood and where there is a significant but incomplete loss of motor neurons, ensuring at least some intact signaling between skeletal muscle and nerve. In addition, generally, there are also no apparent structural abnormalities in the skeletal muscle. The partial loss of motor neurons causes substantial muscle atrophy that in turn leads to many of the motor function impairments. Validated outcome measures, such as the Hammersmith Functional Motor Scale Expanded (“HFMSE”), are available for SMA clinical trials that are relevant to muscle function. These endpoints therefore measure an outcome that may be more likely to be directly affected by apitegromab.

Key disease features of SMA are aligned with Scholar Rock’s guiding principles for neuromuscular indication selection for apitegromab

We are developing apitegromab as a selective muscle-targeted therapy for the treatment of SMA. Myostatin, a member of the TGFβ superfamily of growth factors, is expressed primarily in skeletal muscle cells and the absence of its gene is associated with an increase in muscle mass and strength in multiple animal species. We believe that inhibition of the activation of myostatin may promote a clinically meaningful increase in motor function.

Apitegromab was evaluated in our Phase 2 TOPAZ proof-of-concept clinical trial for the treatment of patients with Type 2 and Type 3 SMA and positive 12-month top-line results were announced in April 2021. We have subsequently presented data from the TOPAZ trial over 24-months (2022), 36-months (2023) and 48-months (2024). See “Phase 2 TOPAZ Proof-of-Concept Trial” below. In October 2024, we announced positive top-line results from SAPPHIRE, a pivotal Phase 3 clinical trial to evaluate the efficacy and safety of apitegromab in patients with nonambulatory Type 2 and Type 3 SMA receiving SMN therapy. We reported that the study achieved its primary endpoint. See “Phase 3 SAPPHIRE Pivotal Trial” below. We submitted a BLA to the FDA in January 2025 and requested priority review, and we plan to submit a marketing authorization application to the EMA in the first quarter of 2025. Assuming marketing approval is obtained, we plan to commercially launch apitegromab in the U.S. in the fourth quarter of 2025 with a commercial launch of apitegromab in Europe to follow.

We believe that apitegromab has the potential to be the first muscle-targeted therapy that is aimed at improving motor function in patients with SMA who are receiving an SMN therapy. We have identified multiple other diseases for which the selective inhibition of the activation of myostatin may offer therapeutic benefit, including additional patient populations in SMA (such as patients under the age of two with SMA and ambulatory patients with SMA) and indications for other neuromuscular disorders beyond SMA.

1. Background on SMA

SMA is a rare, and often fatal, genetic disorder that typically manifests in young children. It is characterized by the loss of motor neurons, atrophy of the voluntary muscles of the limbs and trunk and progressive muscle weakness. Disease severity in SMA can range from patients who die soon after birth to patients who live into adulthood with varying degrees of morbidity. The underlying pathology of SMA is caused by insufficient production of a protein known as “survival of motor neuron,” or SMN. The SMN protein, essential for the survival of motor neurons, is encoded by two genes, SMN1 and SMN2.

2. SMA Natural History and Epidemiology

SMA, the most common monogenic cause of death in infants, is a rare neuromuscular disorder. An estimated 20,000 patients suffer from SMA in the U.S. and Europe alone. Patients with SMA can be categorized as one of four types, Type 1 through Type 4. The majority of SMA patients currently living in the U.S. and Europe are estimated as having Type 2 or Type 3 disease, although it should be noted that this percentage may evolve over time and the definitions of traditional SMA types are themselves evolving. Nonambulatory Type 2 and Type 3 SMA, as they have traditionally been defined, is the initial focus of investigation in our SMA development program.

3. Unmet Medical Need in SMA

We view the emerging landscape for the development of novel medicines for SMA as being classified into two distinct but complementary therapeutic strategies: 1) SMN therapy (also known as SMN corrector therapy or SMN-directed therapy) and 2) muscle-targeted therapy. Despite progress in the development of SMN therapies, a high unmet medical need to improve motor function remains. We believe that the advancement of muscle-targeted therapy will be necessary to address this important gap.

SMN therapies are aimed at addressing the SMN deficiency to prevent further motor neuron deterioration thus modifying the course of disease. This category includes antisense oligonucleotide and small molecule approaches to increase SMN2 expression as well as gene therapy to deliver the SMN1 gene. Early intervention at a very young age is therefore thought to be essential to prevent significant motor functional deterioration. However, for the vast majority of

SMA patients living today, this early intervention window has been missed, and such individuals suffer from severe functional impairment. Thus, regardless of the precise nature or mechanism of action for any given SMN therapy, we believe that most SMA patients will continue to experience clinically significant functional deficits.

To address this need, apitegromab is being developed as a potential first muscle-targeted therapy for SMA. We envision the potential for apitegromab to be standard use with any SMN therapy in patients with Type 2 and 3 SMA in order to drive absolute increases in functional performance over baseline.

4. Clinical Development Overview

We completed SAPPHIRE, a pivotal Phase 3 clinical trial to evaluate the efficacy and safety of apitegromab in patients with nonambulatory Type 2 and Type 3 SMA being treated with SMN therapy. In October 2024, the Company announced positive top-line results that showed the study achieved its primary endpoint.

Beyond Type 2 and Type 3 SMA, we believe that apitegromab has the potential for therapeutic benefit in patients with either more or less severe forms of SMA, as well as pre-symptomatic patients receiving early intervention with a SMN therapy.

Our aim is to develop apitegromab for the broadest group of patients suffering from SMA. The FDA granted Fast Track designation, Rare Pediatric Disease designation and Orphan Drug designation to apitegromab for the treatment of SMA in May 2021, August 2020 and March 2018, respectively. The EMA granted PRIME designation in March 2021 and the EC granted orphan medicinal product designation in December 2018 to apitegromab for the treatment of SMA.

5. Phase 3 SAPPHIRE Pivotal Trial

On October 7, 2024, we announced positive top-line data from our Phase 3 SAPPHIRE clinical trial evaluating the efficacy and safety of apitegromab, an investigational muscle-targeted therapy, in patients with SMA.

SAPPHIRE was a randomized, double-blind, placebo-controlled, Phase 3 clinical trial that evaluated the safety and efficacy of apitegromab in nonambulatory patients with Types 2 and 3 SMA who are receiving current standard of care therapies (either nusinersen or risdiplam). SAPPHIRE enrolled 156 patients ages 2–12 years old in the main efficacy population. These patients were randomized 1:1:1 to receive either apitegromab 10 mg/kg, apitegromab 20 mg/kg, or placebo by intravenous infusion every 4 weeks. An exploratory population that enrolled 32 patients ages 13–21 years old was also evaluated. These patients were randomized 2:1 to receive either apitegromab 20 mg/kg or placebo.

The study achieved its primary endpoint, demonstrating a statistically significant and clinically meaningful improvement for apitegromab compared to placebo in motor function as measured by the HFMSE in SMA patients on chronic dosing of standard of care therapies (either nusinersen or risdiplam). Based upon the similar pharmacological profiles of the 20 mg/kg and 10 mg/kg doses of apitegromab, the statistical analysis plan was prespecified to analyze both the combined dose (10 mg/kg and 20 mg/kg) and the 20 mg/kg dose, each compared to placebo, as the primary analysis. Statistical significance was achieved per the prespecified statistical analysis plan (Hochberg multiplicity adjustment) for the primary analysis where the p-value needs to be ≤0.025 if only one prespecified analysis crosses the statistical significance boundary of ≤ 0.05.

​Motor function outcomes were meaningful and consistent across the main efficacy population and in the ages 13–21 exploratory population, and favored apitegromab (n=22) compared to placebo (n=10).

The table below summarizes the changes from baseline in HFMSE total score at month 12 across the various dose and age groups studied in SAPPHIRE.

Change from Baseline in HFMSE Total Score at Month 12*

Abbreviations: CI, Confidence Interval; LS, Least Squares.

*n values at 12-month endpoint

30.4% of patients receiving apitegromab in the main efficacy population (ages 2-12) had ≥3 point improvement in HFMSE at Month 12 versus 12.5% of patients on placebo, as shown below.

Proportion of Patients With ≥3 Point Improvement at Month 12 in HFMSE

Proportion of patients achieving ≥3 Point Improvement in HFMSE was higher for apitegromab vs. placebo in combined dose (odds ratio 3.0, p=0.0256)

Abbreviation: SOC = standard of care.

Patients receiving apitegromab in the main efficacy population (ages 2–12) demonstrated early motor function improvement compared to placebo from the first measured time point at 8 weeks, and clinical benefit expanded at 52 weeks as measured by HFMSE, as shown below.

HFMSE Improvement vs. Placebo in SAPPHIRE

Abbreviations: CI=Confidence Interval; HFMSE=Hammersmith Functional Motor Scale Expanded; LS=Least Squares; SOC=standard of care.

Treatment with apitegromab was well-tolerated across all age groups. There were no clinically relevant differences in the adverse event profile by dose, 10 mg/kg versus 20 mg/kg. No new safety findings were observed in the SAPPHIRE clinical trial; the profile was consistent with that observed in the Phase 2 TOPAZ clinical trial, including an extension study which had over four years of treatment as of the cut-off date. Serious adverse events (“SAEs”) were consistent with the underlying disease and the current standard of care received by patients; no SAEs were assessed as related to apitegromab. There were no study drug discontinuations due to adverse events. The most common adverse events were pyrexia, nasopharyngitis and cough, observed in 29.2%, 24.5% and 24.5% of patients in the main efficacy population (10 mg/kg and 20 mg/kg combined), respectively. The table below summarizes the adverse events observed in the trial.

Summary of Adverse Events in SAPPHIRE

We are also continuing our long-term extension study, ONYX, for patients from both the TOPAZ and SAPPHIRE studies, who are receiving apitegromab in conjunction with current standard of care. Following trial completion, 98% of SAPPHIRE patients (185/188) enrolled in the ONYX open-label expansion study.

6. Phase 2 TOPAZ Proof-of-Concept Trial

We completed enrollment in our Phase 2 TOPAZ proof-of-concept trial of apitegromab in SMA in January 2020. TOPAZ was a Phase 2 active treatment study evaluating the safety, efficacy, PK, and PD of apitegromab 2 and 20 mg/kg in 58 patients ages 2 to 21 years old with Type 2 and Type 3 SMA (nonambulatory and ambulatory). One patient discontinued from the 12-month treatment period for reasons that were determined to be unrelated to apitegromab treatment. All remaining patients completed the 12-month treatment period and opted into the extension period.

The clinical trial consisted of three distinct cohorts of patients with Type 2 or Type 3 SMA and evaluated the safety and efficacy of apitegromab over a 12-month treatment period. All patients in the clinical trial received apitegromab dosed every four weeks (Q4W) either as a monotherapy or in conjunction with an approved SMN therapy. The primary efficacy objectives evaluated in the TOPAZ trial, HFMSE and Revised Hammersmith Scale (“RHS”), are clinically meaningful outcome measures validated for SMA. The HFMSE is a validated measure for the assessment of gross motor function in SMA, while the RHS is a revised version and used for ambulatory patients in TOPAZ.

Results of the primary analysis showed that improvement in motor function, as measured by RHS or HFMSE, was observed at Month 12 in the majority of patients, regardless of age, SMA type, or time of SMN therapy initiation (Crawford Neurology 2024). Ambulatory patients ages 5 to 21 years old showed stabilization in RHS scores over the 12 months of treatment, while nonambulatory patients showed overall improvement. Substantial improvement in motor function, a mean improvement of 6.2 points for HFMSE total score at Month 12, was observed in Cohort 3, with dose response between those randomized to 20 mg/kg and 2 mg/kg (7.1 points and 5.3 points, respectively).

Treatment with apitegromab was well tolerated. Incidence and severity of adverse events were consistent with the underlying patient population and SMN therapy. The most frequently reported treatment-emergent adverse events included headache (24%), pyrexia (22%), upper respiratory tract infection (22%), cough (22%), and nasopharyngitis (21%). Five patients experienced a serious treatment-emergent adverse event, all assessed by the respective trial investigator as unrelated to apitegromab.

In August 2024, the Company reported that long-term apitegromab data continued to show sustained motor function benefit over 48 months (Crawford WMS 2024). Over 90 percent of nonambulatory patients remained on treatment in the extension study over 48 months. Treatment-emergent adverse events (“TEAEs”) were consistent with previous reports at 12 months, with no new findings.

7. Phase 1 Healthy Volunteer Clinical Trial Results

The randomized, double-blind, placebo-controlled, first-in-human, Phase 1 clinical trial was designed to evaluate the safety and tolerability, immunogenicity, PK, and PD of IV administered apitegromab in adult healthy volunteers. A total of 66 subjects were enrolled, including 40 subjects in the single ascending dose (“SAD”) and 26 subjects in the multiple ascending dose portions of the study. Full results from the Phase 1 clinical trial were presented at the Cure SMA Annual Conference in June 2019.

*Safety and immunogenicity results.*Apitegromab was shown to be well-tolerated with no apparent safety signals. There were no dose-limiting toxicities identified up to the highest tested dose of 30 mg/kg, treatment-related serious adverse events or hypersensitivity reactions. Immunogenicity was assessed by anti-drug antibody testing, and all subjects tested negative.

*Pharmacokinetics and pharmacodynamics results.*Apitegromab displayed a PK profile generally consistent with that commonly observed with monoclonal antibodies. Drug exposure was dose proportional, and the serum half-life was approximately 23 to 33 days across the apitegromab dose groups. The findings supported the investigation of a once every 4-week dosing regimen in the Phase 2 TOPAZ clinical trial.

Mean serum concentrations of latent myostatin in the SAD were < 20 ng/ml in the pre-treatment baselines for apitegromab treated subjects as well as in placebo subjects throughout the study. Following placebo treatment, there was no meaningful change in the latent myostatin biomarker concentrations. Following single doses of apitegromab at dose levels of 3 mg/kg or greater, marked increases in latent myostatin biomarker concentrations in the serum, by at least an order of magnitude, were observed following apitegromab treatment. This finding demonstrates successful target engagement and provides initial proof-of-mechanism in humans of our therapeutic approach of targeting the latent form of growth factors. The observation also corroborates our biological understanding that the vast majority of drug target (pro and latent forms of myostatin) resides within skeletal muscle rather than within the systemic circulation.

Apitegromab engages latent myostatin in Phase 1 clinical trial subjects

8. Apitegromab in Other Disorders Where the Inhibition of Myostatin May Be Beneficial

We see potential for apitegromab broadly across SMA (such as patients under the age of two with SMA and ambulatory patients with SMA) and our intention is to further investigate this potential. We also believe that the role of apitegromab as a muscle-targeted therapy has broad potential beyond SMA, spanning a number of muscle disorders where muscle atrophy is a key component of disease pathogenesis. In some settings, we believe that disease-stabilizing therapy may be necessary to address the underlying defect, which can then be complemented by the potential motor function-building benefit of apitegromab. In settings in which the defect may be less severe and/or the disease may have a slower rate of progression, apitegromab may have the potential to serve as a monotherapy.

Based on this evidence, we believe a wide range of potential therapeutic applications may be envisioned for apitegromab. We are considering the investigation of apitegromab in multiple indications beyond SMA and have efforts underway to evaluate these opportunities (including preclinical and translational research, clinical development and regulatory path assessments, and commercial assessments).

iv. Cardiometabolic Disorders – SRK-439 (inhibitor of latent myostatin)

1. The Current State of Obesity and Obesity Treatment

Obesity is now recognized as a top global public health issue, representing a large market with growing numbers: By the year 2030, it’s estimated that obesity will affect over 1 billion adults and over 250 million children and adolescents. This is a costly chronic disease, associated with more than $170 billion in excess costs annually in the US given serious comorbidities associated with obesity primarily cardiometabolic including cardiovascular disease and type 2 diabetes.

The GLP-1 RAs, and other incretin therapies, have been highly effective in reducing overall weight, but that weight loss includes a significant amount—an estimated 25-40%—of lean muscle mass loss as well. Importantly, there is rebound weight gain upon discontinuation of treatment that is primarily fat with lean muscle mass lagging behind. In addition to the weight gain rebound, patients taking GLP-1 RA therapies have experienced issues with tolerability that influence the duration of treatment and can lead to high rates of discontinuation for these therapies.

2. The Role of Muscle and The Opportunity for Myostatin Inhibition

Muscle plays a key role in metabolic functions and energy homeostasis, and given that important role, we believe that maintaining lean muscle mass is essential for healthy and sustainable weight loss management. The preservation of lean mass has many benefits for overall health above and beyond maintaining strength, especially in the setting of obesity with associated co-morbidities. Specifically, muscle is a metabolic organ and increases basal metabolic rate, enhances glucose uptake, enhances insulin sensitivity, and given the cross talk between adipose tissue and muscle, reduces visceral body fat. All of these functions are important for healthy weight loss management.

The increasing recognition of the important role of skeletal muscle in modulating metabolic physiology highlights a potential therapeutic opportunity for myostatin blockade. For example, data emerging from our preclinical experiments support the hypothesis that blockade of the myostatin pathway has the potential to reduce the mass of visceral fat, a significant driver of cardiometabolic pathophysiology. Excessive fat mass and metabolic abnormalities have been observed in many muscle atrophy states, such as SMA and spinal cord injury. More broadly, reducing visceral fat mass, or improving body compositions (e.g., enhanced muscle-to-fat ratios), may be a potential therapeutic strategy to address a wide range of disorders, such as non-alcoholic steatohepatitis (“NASH”), diabetes, and obesity.

3. SRK-439: A Novel Anti-myostatin Antibody for the Treatment of Obesity

In addition to our work to advance apitegromab in SMA, we have leveraged our expertise in anti-myostatin and its effect on increasing muscle mass to develop myostatin-selective inhibitors for cardiometabolic disorders, including obesity.

SRK-439, a novel anti-myostatin antibody developed by Scholar Rock, has attractive properties that we believe make it specifically suited for the patient population with obesity. These properties include high in vitro affinity for pro- and latent myostatin, maintenance of myostatin specificity (i.e., no GDF11 or Activin-A binding), and a developability profile, including suitability for subcutaneous dosing and a low dosing volume. We believe the selectivity of these antibodies enables a favorable risk-benefit profile for patients with cardiometabolic disorders.

In addition to these properties, SRK-439 has shown robust preclinical efficacy. In two models of DIO mice, SRK-439 maintained lean mass when combined with a GLP-1 RA therapy, either semaglutide or liraglutide. In both cases, adding SRK-439 to semaglutide or liraglutide alone demonstrated dose dependent increase and reversal of lean muscle mass loss with improvement in fat mass loss as well compared to a GLP-1 RA alone (results for SRK-439 used in combination with semaglutide shown below). These results provide the scientific rationale and support the hypothesis that inhibition of myostatin in combination with GLP-1 RA-driven weight loss may lead to retention of lean muscle.

We are advancing this preclinical program and plan to submit an IND in the third quarter of 2025.

SRK-439 Reversed Lean Mass Loss and Enhanced Fat Mass Loss Induced by Semaglutide Treatment. Shown in the plot on the left is the percent change in lean mass from baseline in diet-induced obesity mice as measured by quantitative nuclear magnetic resonance, and on the right, percent change in fat mass in DIO mice.

4. Apitegromab in Obesity: Proof-of-Concept

We see potential for apitegromab as a muscle-targeted therapy broadly across disorders in which the role of muscle is critical for function. To inform the development of SRK-439, in May 2024 we initiated the Phase 2 EMBRAZE proof-of-concept trial, designed to assess the safety and efficacy of apitegromab to preserve muscle mass in individuals living with obesity and on background therapy of a GLP-1 RA. In September 2024, we announced that we completed enrollment and top-line results from this trial are expected in the second quarter of 2025.

We have been a pioneer in developing a differentiated approach to harnessing the therapeutic potential of the TGFβ superfamily of growth factors. The foundation of our industry-leading platform is targeting the TGF superfamily of growth factors with the desired selectivity for both the target (i.e., latent- or pro- form) and disease-specific context. While we are building our experience from this approach with our anti-myostatin pipeline, we have also observed promising preclinical and early clinical data that supports targeting other forms of TGFβ, including for oncology and fibrosis.

The TGFβ superfamily plays a central role in a wide range of cellular processes including growth and differentiation, immune regulation and fibrosis. TGFβ1 is produced by cells as a single protein chain and is then enzymatically processed by the cells into two distinct and physically separated domains — the mature, active growth factor and the remaining portion of the original protein, referred to as the prodomain, or latency associated peptide (“LAP”) — which remains associated with and keeps the growth factor in an inactive state. This complex is further associated with one of a number of “presenting molecules” which when secreted serve to tether the latent precursor in specific locations in the body. TGFβ1 is produced by a variety of cell types, including fibroblasts, which deposit latent TGFβ1 in connective tissue, as well as regulatory T cells, cancer cells and macrophages, which display latent TGFβ1 on their cell surfaces.

In a seminal peer-reviewed publication in 2011, by solving a high-resolution x-ray crystal structure of the latent form of TGFβ1, our founder, Dr. Springer elucidated a new understanding of the mechanism that underlies the activation of latent precursor forms of members of the TGFβ superfamily of protein growth factors. This research explained at a molecular level why the secreted form of TGFβ1 is inactive. The prodomain, though physically separated from the mature growth factor domain, forms a “cage” around the active form of TGFβ1, blocking the ability of the growth factor to signal through its receptor. Integrin proteins are able to unlock the “cage” by binding to the prodomain of the latent

TGFβ1 complex and applying force to pull the complex open, allowing the mature growth factor to be released and signal in its microenvironment. While mature TGFβ1 shares a high degree of structural similarity with its closely related family members, TGFβ2 and TGFβ3, their respective cages are structurally diverse. By taking advantage of the differences among the prodomains, together with our understanding of the activation mechanism and ability to recapitulate the activation mechanism in vitro, we were able to identify multiple highly selective inhibitors of the activation of latent TGFβ1. By specifically targeting the TGFβ1 isoform, we believe we have the key to unlock the power of checkpoint inhibitors and meaningfully increase response rates across multiple solid tumor types. In March 2019, we selected SRK-181 as a product candidate in our TGFβ1 cancer immunotherapy program based on the strength of preclinical data and human translational insights. In vitro and in vivo studies of SRK-181 showed that it binds to latent TGFβ1 with high affinity and high selectivity, which is evidenced by minimal or no binding to latent TGFβ2 or latent TGFβ3 isoforms. Integrins, such as αVβ6 and αVβ8, can trigger the activation of TGFβ1 and TGFβ3. In addition, biochemical evidence suggests that certain proteases (e.g., Plasmin and Kallikreins) may also induce TGFβ activation. Notably, these integrins and proteases have been implicated in tumor biology in a number of human cancers. SRK-181 is capable of inhibiting both integrin-dependent- and protease-induced activation of TGFβ1.

SRK-181 selectively binds to proTGFβ1complexes with minimal or no binding to proTGFβ2 or proTGFβ3 complexes.

i. TGFβ1 in Cancer Therapy

We believe that specific inhibition of TGFβ1 may have a significant impact on the treatment of patients in certain oncology settings.

Immune checkpoints are cellular mechanisms that act as a brake on the immune system, and expression of these proteins in the tumor microenvironment creates an immunosuppressive environment that allows tumor cells to evade being killed by the immune system. Immune checkpoint proteins, such as PD-1/PD-L1, have therefore become key therapeutic targets in the tumor microenvironment. By inhibiting these proteins, the brakes on the immune system are released, allowing the T cells to kill the cancer cells. There are currently multiple approved checkpoint inhibitor therapies that target the PD-1/PD-L1 pathway.

A significant proportion of patients, in many cases the majority, fail to respond to these checkpoint inhibitor therapies, because they have what appears to be a pre-existing, or primary, resistance to immunotherapy. Other patients’ cancers appear to initially respond but subsequently progress (e.g., acquired resistance). In many human cancers, TGFβ signaling is associated with lack of response to PD(L)-1 blockade, particularly in patients with tumors harboring an immune excluded phenotype (i.e., CD8+ T cells present in nearby stroma but excluded from the tumor parenchyma). Gene expression analysis of pre-treatment melanoma tumors identified multiple TGFβ-related signaling signatures associated

with pre-existing or primary resistance to anti-PD-(L)1 antibody therapy. Similarly, it has also been reported that retrospective pathway analysis of tumor samples from an atezolizumab bladder cancer trial identified the TGFβ pathway as a major determinant of primary resistance to atezolizumab.

Our analysis of publicly available human tumor data has identified TGFβ1 as the predominant TGFβ isoform expressed in many human solid tumors.

National Cancer Institute - Cancer Genome Atlas Program RNAseq analysis of >10,000 samples spanning 33 tumor types show high expression of the TGFβ1 isoform in many tumor types

ii. SRK-181 in Cancer Immunotherapy - Inhibitor of Latent TGFβ1 Activation

Our second product candidate, SRK-181, a highly selective inhibitor of the activation of latent TGFβ1, is in clinical development for the treatment of locally advanced or metastatic solid tumors that are resistant to anti-PD-(L)1 therapies. We estimate at least 750,000 cancer patients in the U.S. are eligible for treatment with checkpoint inhibitor therapies every year, of which the majority of patients will develop progression to the treatment.

Increased signaling by TGFβ1 is a key driver of a number of disease-relevant processes, including immune system evasion by cancer cells, bone marrow fibrosis associated with hematological disorders, and tissue and organ fibrosis. Historically, selectively targeting TGFβ1 signaling has been challenging due to the inability of either small molecule inhibitors or antibodies to avoid off-target inhibition of other, closely related growth factors, TGFβ2 and TGFβ3. Treatment of animals with these non-selective TGFβ inhibitors has been associated with a range of toxicities, most notably cardiac toxicity. Furthermore, since each of these growth factors signals through the same TGFβ receptor, ALK5, inhibitors of the TGFβ receptor kinase suffer from similar dose-limiting toxicities. In preclinical studies of our antibodies, we have observed selective inhibition of TGFβ1 activation in vitro and immunomodulatory and antifibrotic activity in multiple disease models in vivo. A 28-day pilot nonclinical toxicology study in rats of our leading antibody did not observe any drug-related toxicity up to the highest dose (100 mg/kg weekly) tested in the study. In the same study, we tested non-selective TGFβ inhibitors and observed the published toxicities, including cardiac toxicity as well as death. We have also completed four-week GLP toxicology studies in rats and non-human primates and no SRK-181 related adverse effects were observed up to the highest evaluated dose of 200 mg/kg per week and 300 mg/kg per week, respectively.

In many human cancers, TGFβ signaling is associated with lack of response to PD-(L)1 blockade, particularly in patients with tumors harboring an immune excluded phenotype (i.e., CD8+ T cells present in nearby stroma but excluded from the tumor parenchyma). We have observed multiple mouse models that recapitulate the immune-excluded phenotype and are resistant to PD-1 blockade become responsive to the combination of SRK-181-mIgG1, the murine analog of SRK-181, and an anti- PD-1 antibody. These models, including the MBT-2 bladder cancer model, the Cloudman S91 melanoma model and the EMT6 breast cancer model, were poorly responsive or unresponsive to single agent treatment with either anti-PD-1 or SRK-181-mIgG1, with little or no effect on tumor growth. However, in representative

experiments, the combination of SRK-181-mIgG1 and anti-PD-1 resulted in tumor regressions of 72%, 57% and 70% in these three mouse models, respectively. Furthermore, the combination treatment led to statistically significant survival benefit in all three models.

Our Phase 1 DRAGON clinical trial is intended to initially evaluate our therapeutic hypothesis that SRK-181 in combination with anti-PD-(L)1 therapy may overcome resistance to anti-PD-(L)1 therapy and lead to anti-tumor responses. This clinical trial in patients with locally advanced or metastatic solid tumors is ongoing and investigates the safety, PK and efficacy of SRK-181. The DRAGON trial consists of two parts: Part A (dose escalation of SRK-181 as a single-agent or in combination with an approved anti-PD-(L)1 therapy) and Part B (dose expansion evaluating SRK-181 in combination with an approved anti-PD-(L)1 antibody therapy). Part B encompasses five active cohorts, including urothelial carcinoma, cutaneous melanoma, non-small cell lung cancer, clear cell renal cell carcinoma and head and neck squamous cell carcinoma, and commenced in 2021 and completed enrollment in December 2023. We continue to treat patients who remain on study. Safety, efficacy and biomarker data were presented in June 2024 at the ASCO annual meeting and in November 2024 at the SITC 39th Annual Meeting. The data showed encouraging responses in heavily pretreated and anti-PD-(L)1 resistant patients across multiple tumor types. Data presented continues to support proof-of-concept for SRK-181 in 30 heavily pretreated patients with ccRCC resistant to anti-PD-1. SRK-181 was generally well tolerated and showed promising anti-tumor activity in this patient population. Of 30 patients in the ccRCC cohort, seven patients treated with SRK-181 in combination with pembrolizumab had documented response, achieving a best tumor reduction of 40% to 100%, with an objective response rate of 23.3%. In the biomarker analysis, SRK-181 combined with pembrolizumab established proof of mechanism in patients by creating a proinflammatory tumor microenvironment across multiple tumor types. Safety data from ccRCC cohort continue to show SRK-181 is generally well tolerated. In ccRCC patients, responders had higher basal levels of activated CD8+ T cells, higher T-regs, as well as higher TGFβ1 expression. The data cutoff for all analyses was September 9, 2024.

We believe that the DRAGON trial achieved its study objectives by showing objective, durable clinical responses in patients with ccRCC resistant to PD-1 therapy beyond what is expected from continuing PD-1 alone. We anticipate that emerging data from the DRAGON trial will be presented at medical meetings in the future.

1. Potential Applications of SRK-181 in Additional Oncology Settings

In addition to cancer immunotherapy, we believe SRK-181 has the potential for use in other oncology settings, such as in immunotherapy-naïve patients, in combination with other therapies beyond checkpoint inhibitors and in myelofibrosis.

iii. Fibrosis: LTBP-49247

Fibrosis is a pathological feature of many diseases and can occur in virtually all organs. It is characterized by excessive accumulation of extracellular matrix in the affected tissue and accounts for substantial morbidity and mortality. TGFβ signaling pathway is a well-established central driver in the pathogenesis of fibrotic diseases and inhibition of this pathway has been shown to improve outcomes in relevant animal models of hepatic, renal, pulmonary, and other fibrotic diseases. In addition, a non-selective inhibitor of TGFβ signaling that inhibits all 3 isoforms (isoform 1, 2, and 3) of TGFβ showed clinical improvement in patients with systemic sclerosis, a fibrotic connective tissue disease. However, non-selective inhibition of all TGFβ isoforms is known to be associated with serious safety findings, most notably bleeding episodes, and cardiac toxicities. Based on knock out animal models (a model where researchers have inactivated, or "knocked out," an existing gene by replacing it or disrupting it with an artificial piece of DNA), these safety findings are believed to be associated with inhibition of the TGFβ2, and TGFβ3 isoforms. These data suggest that novel approaches to targeting TGFβ signaling may have broad applicability to the treatment of fibrotic disease, where more selective approaches may offer an improved safety profile. In addition, given that immune cell activation may play a key role in fibrotic disease development, selective targeting of only matrix associated TGFβ1, at the primary site of fibrosis manifestation, while avoiding immune cell associated TGFβ1 is key to maintaining efficacy while avoiding potential long-term liabilities of immune cell activation.

Based on this scientific rationale, we utilized our platform to discover and develop antibodies that selectively inhibit the activation of latent TGFβ1 in the context of fibrotic extracellular matrix and that avoid perturbing TGFβ1 presented by cells of the immune system. We selected SRK-373, a highly potent, anti-latent TGFβ1 antibody that selectively inhibits

TGFβ1 activation within the extracellular matrix by targeting latent TGFβ1 associated with latent TGFβ-binding proteins (LTBPs), thus enabling specific inhibition of TGFβ1 in fibrotic tissue. This antibody demonstrated significant antifibrotic activity in a variety of preclinical rodent models. It also demonstrated robust therapeutic index at all doses tested in a non-GLP mouse safety study. We plan to advance this program to IND-enabling studies.

When latent TGFβ1 is secreted from cells (top center), it is further associated with another protein, referred to as a presenting molecule (examples of which are shown in each image). The presenting molecules are covalently bound to the prodomain and serve to tether the latent TGFβ1 complex in a particular microenvironment. Unlike TGFβ1, a given presenting molecule's expression pattern is restricted to particular cellular and tissue environments. For example, the presenting molecule GARP (right) is found primarily on regulatory T cells, the presenting molecules LTBP1 and LTBP3 (bottom center) are localized to the connective tissue in the extracellular matrix, and the presenting molecule LRRC33 (left) is found primarily on certain myeloid lineage cells such as macrophages.

A number of disease states as well as rare genetic mutations can cause disruptions in iron homeostasis and can result in either iron deficiency or overload. These imbalances in iron levels can lead to detrimental complications and are the basis of mortalities and morbidities in many diseases. Hepcidin is a peptide hormone that is produced in the liver and plays a major role in regulating systemic iron homeostasis. Aberrantly increased hepcidin expression is a hallmark of several chronic and devastating diseases where it causes iron-restricted anemia, contributing to the morbidity and mortality of these diseases. Hepcidin expression is controlled via the bone morphogenetic protein (BMP) signaling pathway, with BMP2/6 being the predominant ligands signaling through a large protein receptor complex containing BMP receptors (BMPR) and a BMP co-receptor, repulsive guidance molecule c/ hemojuvelin (RGMc/HJV). The RGM family consists of three members, RGMa, RGMb and RGMc/HJV, and owing to their role as BMP co-receptors, has been shown to be involved in the development and maintenance of many tissues and organs throughout the body. Human mutations as well as knockout animal studies have demonstrated the predominant role of RGMc/HJV to be in the

regulation of iron homeostasis. These data suggest that novel approaches to specifically target the BMP pathway in the liver may have a broad applicability to the treatment of anemia, especially in chronic diseases where hepcidin is upregulated.

In contrast to the far-reaching roles of BMP-BMPRs throughout the body, the specific role of RGMc/HJV isoform in iron homeostasis, provided an opportunity to utilize our platform to discover and develop antibodies that selectively bind to and inhibit RGMc. We selected SRK-256, a highly potent and selective RGMc/HJV inhibitor that has demonstrated significant suppression of hepcidin expression and resultant mobilization of stored iron in vivo in mice, rats, and non-human primates. SRK-256 may provide a novel approach to treating iron-restricted anemia in patients with chronic diseases driven by hepcidin overexpression. We plan to advance this program to IND-enabling studies.

d. Additional Potential Areas of Exploration

Additional therapeutic areas and targets in which we could potentially apply our scientific platform and expertise include:

We continue to enhance our internal biologics discovery capabilities including the acquisition and development of our own proprietary single-domain antibody libraries. These new capabilities allow us to more efficiently discover antibodies and furthers our commitment to building a differentiated portfolio of product candidates.

a. Gilead Collaboration

On December 19, 2018 (the “Effective Date”), we entered into a three-year collaboration with Gilead to discover and develop therapeutics that target TGFβ-driven signaling, a central regulator of fibrosis (“the Collaboration Agreement”). In connection with the Collaboration Agreement, we received an upfront payment of $50 million and an equity investment of $30 million.

In December 2019, we achieved a $25 million preclinical milestone under the Gilead Collaboration Agreement for the successful demonstration of efficacy in preclinical in vivo proof-of-concept studies.

On January 6, 2022, we entered into a letter agreement with Gilead which (i) confirmed that the collaboration period under the Collaboration Agreement had expired as of December 19, 2021, and (ii) agreed the option exercise period for all programs under the Collaboration Agreement had been terminated as of January 6, 2022.

b. Adimab Agreement

On March 12, 2019, we entered into an amended and restated collaboration agreement (“Adimab Agreement”) with Adimab, LLC (“Adimab”). Under the Adimab Agreement, as amended, we selected a number of biological targets against which Adimab used its proprietary platform technology to discover and/or optimize antibodies based upon mutually agreed upon research plans, and we have the ability to select a specified number of additional biological targets against which Adimab will provide additional antibody discovery and optimization services. During the research term

and evaluation term for a given research program with Adimab (“Research Program”), we have a non-exclusive worldwide license under Adimab’s technology to perform certain research activities and to evaluate the program antibodies to determine whether we want to exercise our option to obtain an exclusive license to exploit such antibodies (a “Development and Commercialization Option”).

Pursuant to the Adimab Agreement, we previously paid Adimab a one-time, non-creditable, non-refundable technology access fee. We are also obligated to make certain technical milestone payments to Adimab on a Research Program-by-Research Program basis. Upon exercise of a Development and Commercialization Option, we are obligated to pay to Adimab a non-creditable, nonrefundable option exercise fee of either (i) a low seven-digit dollar amount or (ii) a mid- six-digit dollar amount, based on the antibodies in the given Research Program, plus, in either case, an amount equal to any technical milestone payment which was not previously paid with respect to such Research Program and less, in either case, any option extension fees paid with respect to such Research Program. On a Product (as defined in the Adimab Agreement)-by-Product basis, we will pay Adimab upon the achievement of various clinical and regulatory milestone events with total milestone payments not to exceed mid-teen millions in the aggregate for a given Product. For any Product that is commercialized, on a country-by-country and Product-by-Product basis, we are obligated to pay to Adimab a low-to-mid single-digit percentage of annual worldwide net sales of such Product during the applicable royalty period in each country.

SRK-181 is subject to the terms of the Adimab Agreement, and in March 2019, we exercised our Development and Commercialization Option for the Research Program from which SRK-181 was generated. In January 2020 and December 2020, we exercised our Development and Commercialization Option for additional Research Programs.

Our commercial success depends in part on our ability to protect intellectual property for our product candidates, including apitegromab and SRK-181, and related methods, as well as our novel approach and proprietary platform for generating monoclonal antibodies; to secure freedom-to-operate to enable commercialization of our product candidates, if approved; and to prevent others from infringing upon our patent rights. Our policy is to seek to protect our intellectual property position by filing patent applications in key jurisdictions, including the U.S., Europe, Canada, Japan and Australia, covering our proprietary technology, inventions and improvements that are important to innovate, develop, sustain and implement our business.

We file patent applications directed to compositions comprising our antibodies, classes of antibodies covering our product candidates, use of such antibodies for treating diseases, as well as related manufacturing methods. As of December 31, 2024, we have 30 pending patent families across multiple programs. Among the pending families, 24 have been nationalized, from which 24 applications have matured into U.S. issued patents with additional issued patents in multiple jurisdictions globally. Collectively, there are 337 national or direct utility applications pending or issued. In addition, there are four patent family filings which are in the priority year. We continue to review and harvest new inventions for new patent filings.

As of December 31, 2024, three granted patents, EP2981822, EP2981822 and EP3368069, are the subject of ongoing opposition proceedings before the European Patent Office (“EPO”). We have no other contested proceedings relating to any patents as of that date, but we cannot provide any assurances that we will not have such proceedings at a later date. For more information regarding the risks related to our intellectual property, please see “Risk factors—Risks Related to Our Intellectual Property.”

a. Platform

Our novel approach to generating selective modulators of supracellular activation of growth factors is broadly embodied in our earliest “platform” patent family, PCT/US2014/036933 (published as WO 2014/182676). This patent family is directed to methods for modulating the activation of the TGFβ superfamily of growth factors and methods for screening for a monoclonal antibody that specifically targets an inactive form of the growth factor, thereby preventing activation (e.g., release) of mature growth factor. The TGFβ superfamily is a group of more than 30 related growth

factors/cytokines that mediate diverse biological processes and includes TGFβ1 and myostatin (also known as GDF-8). Issued U.S. patents in the platform family include: U.S. Patents Nos. 9,573,995 (issued 02/21/2017); 9,758,576 (issued 09/12/2017); 9,580,500 (issued 02/28/2017); 9,399,676 (issued 07/26/2016); 9,758,577 (issued 09/12/2017); 10,597,443 (issued 03/24/2020); 10,981,981 (issued 04/20/2021); and 11,827,698 (issued 11/28/2023). There is also a granted European (“EP”) platform patent: EP2981822 (granted on 09/02/2020). These U.S. and EP patents are projected to expire in 2034.

Specifically, EP2981822 originally granted with composition of matter claims directed to an antibody capable of binding a recombinant antigen comprising pro-TGFβ1 or a growth factor-prodomain complex which comprises the TGFβ1 LAP complex, in addition to claims directed to methods of making such antibodies. EP2981822 is the subject of ongoing opposition proceedings before the EPO. It was revoked by the opposition division in November 2024, but the revocation decision is subject to appeal.

U.S. Patent No. 9,573,995 has issued composition of matter claims directed to an antibody that specifically binds to GARP associated with a human TGFβ1 LAP complex.

U.S. Patent No. 9,758,576 has issued composition of matter claims directed to an isolated monoclonal antibody, or a fragment thereof, that specifically binds the prodomain of a pro/latent GDF-8/myostatin complex, thereby preventing proteolytic cleavage between residues Arg 75 and Asp 76 of GDF-8/myostatin prodomain, so as to inhibit the release of mature GDF-8/myostatin growth factor from the complex.

U.S. Patent No. 9,580,500 has issued claims directed to phage display library-based antibody production methods for identifying an antibody that binds a GARP/proTGFβ1 complex.

U.S. Patent No. 9,399,676 has issued claims directed to phage display library-based antibody production methods for identifying an antibody that binds a pro/latent GDF-8 complex that has been subjected to enzymatic cleavage. Related product-by-process claims are included in issued U.S. Patent No. 9,758,577.

U.S. Patent No. 10,597,443 has issued claims that broadly cover manufacturing methods for a pharmaceutical composition containing an antibody that binds a large latent complex of TGFβ, thereby modulating TGFβ signaling.

U.S. Patent No. 10,981,981 has issued claims that broadly cover manufacturing methods for a pharmaceutical composition containing an antibody that binds pro/latent GDF-8, but does not bind to mature GDF-8, and inhibits GDF-8 signaling.

In addition, U.S. Patent No. 11,827,698 has issued claims that broadly cover manufacturing methods for a pharmaceutical composition containing an antibody that binds pro/latent GDF-8, and inhibits release of mature GDF8 from the pro/latent GDF8 complex.

b. Myostatin Activation Inhibitors

Thirteen patent families have been filed to date to cover proprietary myostatin inhibitors and their use in the treatment of various muscle and metabolic diseases. Patent prosecution of these pending patent families is ongoing but relatively early.

Three families are directed to composition of matter claims that cover our proprietary antibodies. PCT/US2015/059468 (published as WO 2016/073853) broadly covers a class of monoclonal antibodies that specifically bind inactive precursors thereby preventing activation of myostatin. This patent family is projected to expire in November 2035. U.S. Patents 10,307,480, 11,135,291, and 11,925,683 issued in June 2019, October 2021, and March 2024, respectively, with claims directed to Scholar Rock proprietary antibodies that specifically bind pro/latent myostatin, including 29H4, the parental clone of apitegromab, and variants, as well as host cells and methods of making antibodies with pH sensitive binding to pro/latent myostatin.

A second family, PCT/US2016/052014 (published as WO 2017/049011), discloses the specific amino acid sequence of apitegromab and is projected to expire in September 2036. U.S. Patent 10,751,413 issued in August 2020, with claims directed to antibodies and pharmaceutical compositions comprising the heavy and light chain sequences of apitegromab, while U.S. Patent 11,439,704 issued in September 2022, with claims directed to a method of preventing muscle loss and/or reducing muscle atrophy or treating SMA by administering an antibody having the heavy and light chain sequences of apitegromab. The European counterpart also granted as EP 3350220 B1 in May 2021. The granted claims relate to antibodies comprising the heavy and light chain variable region and full chain sequences of apitegromab, and pharmaceutical compositions of the antibodies.

A third family, PCT/US2023/085574 (published as WO2024138076), was filed with claims directed to specific amino acid sequences of additional antibodies in our proprietary myostatin inhibitor portfolio. If granted, this family is projected to expire in December 2043.

The following patent families are directed to therapeutic uses/methods:

PCT/US2017/012606 (published as WO 2017/120523) broadly covers treatment methods for a number of muscle and neuromuscular disease and disorders using an antibody that specifically blocks the activation step of myostatin. This family is projected to expire in September 2036. The first U.S. application issued in May 2019 as U.S. Patent 10,287,345 with claims drawn to methods for inhibiting myostatin activation using our proprietary activation inhibitors (such as apitegromab) to cause specified pharmacological effects to treat a variety of conditions including, muscle and metabolic disorders. A second U.S. application issued as U.S. Patent 10,882,904 in January 2021. The issued claims recite methods for inhibiting myostatin activation using an antibody comprising the heavy and light chain sequences of apitegromab for various indications. A third U.S. application issued as U.S. Patent 12,006,359 in June 2024. The issued claims are directed to a method of improving body composition by administering an antibody comprising heavy and light chain sequences of our proprietary activation inhibitors (such as apitegromab) or variants thereof.

PCT/US2017/037332 (published as WO 2017/218592) is directed to methods for treating neuromuscular diseases and selecting patient populations that are likely to respond to myostatin inhibition. This filing includes the treatment of SMA in patients who are on SMN therapies (e.g., SMN correctors/upregulators). This patent family is projected to expire in June 2037. The PCT application was nationalized in 11 jurisdictions, and applications in the three key jurisdictions (i.e., U.S., Europe and Japan) have granted, as well as in other countries. Specifically, the U.S. application granted in March of 2021 as U.S. Patent 10,946,036. The granted claims are directed to add-on or combination therapy for treating spinal muscular atrophy with a myostatin inhibitor and a neuronal corrector (such as smn upregulator therapy). Similar claims have also granted in other countries including Japan (JP Patent No. 6823167, JP Patent No. 7161554, and JP Patent No. 7344337). Likewise, the European counterpart granted as EP 3368069B1 and has been validated in 37 states. The originally granted European claims are directed to add-on therapy and combination therapy for the treatment of SMA using a myostatin-selective inhibitor, in conjunction with an SMN corrector therapy. EP 3368069B1 is currently the subject of ongoing opposition proceedings before the EPO. It was revoked by the opposition division in April 2024, but the revocation decision is being appealed.

PCT/US2018/012686 (published as WO 2018/129395) relates to the treatment of metabolic diseases with a myostatin activation inhibitor and is projected to expire in January 2038. The PCT was nationalized in 2019 and is in the early stages of prosecution. A U.S. patent issued in October of 2021 as U.S. 11,155,611, with claims directed to methods of making a pharmaceutical composition comprising a myostatin-selective inhibitor, comprising screening for an antibody that is capable of decreasing expression of pyruvate dehydrogenase kinase 4 (PDK4) and increasing expression of pyruvate dehydrogenase phosphatase 1 (PDP1). A Japanese patent (JP 7198757) issued in December 2022 with claims directed to a pro/latent myostatin-specific inhibitor for use in treating or preventing obesity or metabolic disorder in a subject on a calorie restriction diet. Similar claims have issued in Europe in 2023 (EP 3565592).

In addition to the five pending patent families listed above, there are also two PCT applications related to the phase 2 and phase 3 clinical trials of apitegromab in SMA. PCT/US2021/056517 (published as WO2022/093724) is directed to inventions deriving from the phase 2 clinical trial of apitegromab. This PCT was nationalized broadly. If granted, patents deriving from this PCT would expire in 2041. Another PCT application was filed in 2023, PCT/US2023/020843

(published as WO 2023/215384) with claims directed to therapeutic methods for treating SMA deriving from the phase 2 and phase 3 clinical trials of apitegromab. If granted, patents from this family would expire in 2043. Both of these families are in early stages of prosecution.

A further PCT application PCT/US2022/034588 (published as WO2022/2271867) was filed with claims directed to a myostatin pathway inhibitor for use in treating metabolic disorders. If granted, patents deriving from this PCT would expire in 2042.

Finally, five other myostatin-related patent families have been filed and are in the priority year.

c. TGFβ1 Activation Inhibitors

In addition to the patent families discussed above in the “Intellectual Property-Platform” section that generically cover certain aspects of the TGFβ1 program, fifteen patent families have been filed to date, covering various specific aspects of our TGFβ1 programs.

Isoform-specific inhibitors of TGFβ1 which confer improved safety profile and related methods are described in PCT/US2017/021972 (published as WO 2017/156500). A U.S. patent (11,643,459) issued in May 2023, with claims directed to methods for identifying TGFβ1-specific inhibitors. A European patent granted in May of 2023 as EP3365368, with claims to the use of isoform-selective and context-independent anti-TGFβ1 antibodies, defined by CDR sequences or by cross-competition, in the treatment of cancer or myelofibrosis. EP3365368 is the subject of ongoing opposition proceedings before the EPO. Additional patents in this family have been granted in other jurisdictions. This family is projected to expire in March 2037.

Among TGFβ1 inhibitors, one of our context-independent antibodies is separately claimed and related preclinical data are described in PCT/US2018/012601 (published as WO 2018/129329). This patent application is projected to expire in January 2038. For this latter family, a Japanese patent (JP Patent No. 7157744) issued in October 2022 with claims covering certain isoform-selective, context-independent antibodies and their use in the treatment of fibrotic diseases.

In addition, high-affinity, isoform-selective TGFβ1 inhibitors are disclosed in PCT/2019/041373 (published as WO US2020/014460, and patents have issued in April 2024 in Columbia, June 2024 in the Gulf Cooperation Council, and August of 2024 in Japan). Patents of this family are projected to expire in 2039. Separately, direct national/regional applications covering related subject matter have been filed, in the U.S., Europe and Hong Kong, and are projected to expire in 2039. Two U.S. patents issued in September of 2021 as U.S. 11,130,803 and in October of 2024 as U.S. 12,122,823, with claims which cover the SRK-181 clinical candidate and pharmaceutical compositions thereof; and a European patent issued in November of 2021 as EP3677278; and the corresponding Hong Kong patent issued in June of 2022, with claims that cover the SRK-181 clinical candidate, pharmaceutical compositions, use for treating cancer and myelofibrosis, and methods for manufacturing. Additionally, PCT/US2021/012969 (published as WO 2021/142448) discloses data related to biomarkers for the high-affinity, isoform-selective TGFβ1 inhibitors and, if granted, patents deriving from this PCT application are projected to expire in 2041. Additional biomarkers are disclosed in PCT/US2022/022063 (published as WO2022/204581). If granted, patents deriving from these PCT applications would expire in 2042. Another PCT application, PCT/US2024/018970 (published as WO 2024/187051) discloses methods of treating certain cancers and identification of patient populations using biomarkers. If granted, patents derived from this PCT is expected to expire in 2044. One additional patent family to our TGFβ1 inhibitor program is currently in the priority year. Antibodies claimed in these patent families protect our SRK-181 clinical candidate.

Separately, other improved isoform-selective, context-independent inhibitors of TGFβ1 are disclosed in PCT/US2019/041390 (published as WO 2020/014473). This family is projected to expire in 2039. PCT/US2021/12930 (published as WO 2021/142427) is directed to optimized isoform-selective, context-independent inhibitors of TGFβ1. This family is projected to expire in 2041.

LTBP complex-specific inhibitors of TGFβ1 are described in four patent families: PCT/US2018/44216 (published as WO 2019/023661) which is expected to expire in July of 2038; and PCT/US2020/15915 (published as WO2020/160291), which is expected to expire in 2040; PCT/US2022/73740 (published as WO 2023/288277), which is expected to expire in 2042. Three U.S. patents (U.S. Pat. Nos. 11,214,614, 11,365,245 and 12,173,059) and one Columbian patent have been issued in the second patent family with claims directed to antibodies and pharmaceutical compositions.

LRRC33-specific inhibitors are described in a further patent family: PCT/US2018/031759 (published as WO 2018/208888) which is expected to expire in May of 2038. EP3621694 granted in July 2023, with claims directed to therapeutic use of LRRC33 inhibitors for the treatment of various indications. PCT/US2017/042162 (published as WO 2018/013939) was exclusively licensed to Janssen but, as explained below, the license agreement was terminated in July 2022. Scholar Rock is now in control of prosecution. This patent family covers antibodies that specifically inhibit GARP-associated TGFβ, and is projected to expire in July 2037. A Japanese patent (JP Patent No. 7128801) issued in August 2022 with claims directed to antibodies and antigen-binding fragments which specifically bind human pro-TGFβ 1-GARP complex, a process for their production and related compositions. Additional patents have also granted in other jurisdictions including in Australia (AU 2017294772).

d. RGMc-Selective Inhibitors

PCT/US2019/057687 (published as WO2020/086736) is directed to RGMc-selective inhibitors and is projected to expire in 2039. A Japanese patent application was allowed in December 2024 and will grant in early 2025. The Japanese patent will have claims which cover a pharmaceutical composition comprising the SRK-256 clinical candidate and the use thereof for treating anemia, including anemia of chronic disease and anemia in subjects diagnosed with cancer, such as myelofibrosis. Also, a Chinese patent application was allowed in December 2024, with similar claims. Applications are pending in other jurisdictions, including U.S. and EP.

e. Intellectual Property Protection

We cannot predict whether the patent applications we pursue will issue as patents in any particular jurisdiction or whether the claims of any issued patents will provide any proprietary protection from competitors. Even if our pending patent applications are granted as issued patents, those patents, as well as any patents we license from third parties, may be challenged, circumvented or invalidated by third parties. As mentioned above, three granted patents, EP2981822, EP3365368 and EP3368069, are the subject of ongoing opposition proceedings before the EPO, as of December 31, 2024. While there are no contested proceedings or third-party claims relating to any of the other patents described above, as of that date, we cannot provide any assurances that we will not have such proceedings or third-party claims at a later date.

Additionally, the Unitary Patent/Unified Patent Court system in Europe became fully operational in June 2023. As such, European patents which are subject to the jurisdiction of the Unified Patent Court (“UPC”) face limited precedent for the court, increasing the uncertainty of any litigation.

The term of individual patents depends upon the legal term of the patents in the countries in which they are obtained. In most countries in which we file, the patent term is 20 years from the earliest date of filing a non-provisional patent application. In the U.S., the patent term of a patent that covers an FDA-approved drug or biologic may also be eligible for patent term extension, which permits patent term restoration as compensation for the patent term lost during FDA regulatory review process. The Hatch-Waxman Amendments permit a patent term extension of up to five years beyond the expiration of the patent. The length of the patent term extension is related to the length of time the drug or biologic is under regulatory review. Patent term extension cannot extend the remaining term of a patent beyond a total of 14 years from the date of product approval and only one patent applicable to an approved drug or biologic may be extended. Similar provisions are available in Europe and other foreign jurisdictions to extend the term of a patent that covers an approved drug or biologic or provide an additional period of protection for the approved pharmaceutical product following expiry of the patent. In the future, if our products receive FDA approval, we expect to apply for patent term extensions on patents covering those products. We plan to seek patent term extensions to any of our issued patents in any

jurisdiction where these are available, however there is no guarantee that the applicable authorities, including the U.S. Patent and Trademark Office in the U.S. and the national patent offices in Europe, will agree with our assessment of whether such extensions should be granted, and if granted, the length of such extensions.

In addition to our reliance on patent protection for our inventions, product candidates and research programs, we also rely on trade secret protection for our confidential and proprietary information. For example, certain elements of our proprietary platform may be based on unpatented trade secrets that are not publicly disclosed. Although we take steps to protect our proprietary information and trade secrets, including through contractual means with our employees and consultants, third parties may independently develop substantially equivalent proprietary information and techniques or otherwise gain access to our trade secrets or disclose our technology. Thus, we may not be able to meaningfully protect our trade secrets. It is our policy to require our employees, consultants, outside scientific collaborators, sponsored researchers and other advisors to execute confidentiality agreements upon the commencement of employment or consulting relationships with us. These agreements provide that all confidential information concerning our business or financial affairs developed or made known to the individual or entity during the course of the party's relationship with us is to be kept confidential and not disclosed to third parties except in specific circumstances. In the case of employees, the agreements provide that all inventions conceived by the individual, and which are related to our current or planned business or research and development or made during normal working hours, on our premises or using our equipment or proprietary information, are our exclusive property. In addition, we take other appropriate precautions, such as physical and technological security measures, to guard against misappropriation of our proprietary technology by third parties. We have also adopted policies and conduct training that provides guidance on our expectations, and our advice for best practices, in protecting our trade secrets.

IX.Manufacturing

We do not own or operate facilities for clinical drug manufacturing, storage, distribution or quality testing. Currently, all of our clinical manufacturing is outsourced to third-party manufacturers. Certain third party manufacturers may require us to enter in manufacturing agreements with them that include substantial milestone payments and royalties. As our development programs expand and we build new process efficiencies, we expect to continually evaluate our strategy of utilizing third party manufacturers with the objective of satisfying demand for our registration trials and, if approved, the manufacture, sale and distribution of commercial products.

X.Antibody Discovery

We have internal antibody display and discovery capabilities; however, at times we may continue to rely on third parties to conduct antibody discovery and optimization services for us based on criteria and specifications provided by us. Certain antibody discovery and optimization vendors require us to enter into a license with them for the right to use antibodies discovered by them in human use or for commercial purposes. Such license could include substantial milestone payments and royalties to the extent we choose to use an antibody discovered by such vendor. On March 12, 2019, we exercised an option to receive such a license from Adimab pursuant to our Adimab Agreement. Please see the description above in “License Agreements – Adimab Agreement” for more details on the terms of this agreement.

XI.** Competition**

The biotechnology and pharmaceutical industries are characterized by rapid evolution of technologies, fierce competition, and strong defense of intellectual property. Although we believe that our product candidates, discovery programs, technology, knowledge, experience and scientific resources provide us with competitive advantages, we face competition from major pharmaceutical and biotechnology companies, academic institutions, governmental agencies and public and private research institutions, among others.

Many of the companies against which we may compete have significantly greater financial resources and expertise than we do in research and development, manufacturing, and commercialization of approved products. These competitors compete with us in recruiting and retaining qualified scientific and management personnel and may compete with us in establishing clinical trial sites and patient recruitment for clinical trials.

The availability of reimbursement from government and other third-party payors will also significantly affect the pricing and competitiveness of our products. Our competitors also may obtain FDA or other regulatory approval for their products more rapidly than we may obtain approval for ours, which could result in our competitors establishing a strong market position before we are able to enter the market.

a. Competition for Apitegromab

In the SMA market, there are three approved SMN targeted treatments and no approved muscle-targeted treatments for SMA to date. The SMA drug development pipeline reflects a focus on addressing the significant remaining unmet needs of individuals living with SMA as well as the life cycle management of the existing approved SMN targeted treatments. To address the remaining unmet needs to further improve and sustain muscle function by contributing to the impact on the overall disease progression in SMA, we are pioneering a novel approach by developing the first muscle-targeted treatment in SMA.

We are developing apitegromab, an investigational fully human monoclonal antibody designed to inhibit myostatin activation by selectively binding the pro- and latent forms of myostatin in the skeletal muscle, for the treatment of patients with SMA. If apitegromab receives marketing approval, we may face competition from other companies conducting clinical trials to develop anti-myostatin molecules or other treatments for SMA, including Roche, Biogen, and NMD Pharma. Moreover, we may also compete with smaller or earlier-stage companies, and other research institutions that have developed, are developing or may be developing current and future anti-myostatin inhibitors or other treatments for SMA.

In addition, Novartis, Roche and Biogen are in late-stage development of alternate formulations or dosing regimen of their respective approved SMN treatments, including an additional formulation of Novartis’ onasemnogene abeparvovec, an oral tablet for Roche’s risdiplam, as well as a high dose formulation of Biogen’s antisense oligonucleotide (ASO), nusinersen. Apitegromab is being developed with the intention to be used in individuals living with SMA who are currently on an approved SMN targeted treatment.

b. Competition for SRK-181

Our competitors for SRK-181 may include other companies developing inhibitors of the TGFβ signaling pathway, such as antifibrotic therapies and cancer immunotherapies to be used in combination with CPI therapy.

For the latter, many companies, including AbbVie Inc, Roche, Bicara Therapeutics, Novartis, Bristol Myers Squibb (acquired Forbius) and Merck KGaA, Merck (acquired Tilos Therapeutics) are developing therapies for cancer immunotherapy in combination with CPI therapy, that are intended to work, at least in part, through inhibition of the TGFβ signaling pathway.

Our competitors may also include companies that are or will be developing therapies for the same therapeutic areas that we are targeting within our early pipeline, including other neuromuscular disorders, cancer, fibrosis and iron-restricted anemia.

XII.** Government Regulation**

Government authorities in the U.S. at the federal, state and local level and in other countries regulate, among other things, the research, development, testing, manufacture, quality control, approval, labeling, packaging, storage, record-keeping, promotion, advertising, distribution, post-approval monitoring and reporting, marketing and export and import of drug and biological products, such as apitegromab, SRK-181, SRK-439 and any future product candidates. Generally, before a new drug or biologic can be marketed, considerable data demonstrating its quality, safety and efficacy must be obtained, organized into a format specific for each regulatory authority, submitted for review and approved by the regulatory authority.

a. U.S. Biological Product Development

In the U.S., the FDA regulates drugs under the Federal Food, Drug, and Cosmetic Act (“FDCA”), and its implementing regulations and biologics under the FDCA, the Public Health Service Act (“PHSA”), and their implementing regulations. Both drugs and biologics also are subject to other federal, state and local statutes and regulations. The process of

obtaining regulatory approvals and the subsequent compliance with appropriate federal, state and local statutes and regulations requires the expenditure of substantial time and financial resources. Failure to comply with the applicable U.S. requirements at any time during the product development process, approval process or post-market may subject an applicant to administrative or judicial sanctions. These sanctions could include, among other actions, the FDA’s refusal to approve pending applications, withdrawal of an approval, a clinical hold, untitled or warning letters, product recalls or market withdrawals, product seizures, total or partial suspension of production or distribution, injunctions, fines, refusals of government contracts, restitution, disgorgement and civil or criminal penalties. Any agency or judicial enforcement action could have a material adverse effect on us.

Apitegromab, SRK-181, and any future product candidates regulated as biologics must be approved by the FDA through a BLA process before they may be legally marketed in the U.S. The process generally involves the following:

i. Preclinical Studies and IND

Preclinical studies include laboratory evaluation of product chemistry and formulation, as well asin vitro and animal studies to assess the potential for adverse events and in some cases to establish a rationale for therapeutic use. The conduct of preclinical studies is subject to federal regulations and requirements, including GLP regulations for safety/toxicology studies.

An IND sponsor must submit the results of the preclinical tests, together with manufacturing information, analytical data, any available clinical data or literature and plans for clinical studies, among other things, to the FDA as part of an IND. An IND is a request for authorization from the FDA to administer an investigational product to humans, and must become effective before human clinical trials may begin. Some long-term preclinical testing may continue after the IND

is submitted. An IND automatically becomes effective 30 days after receipt by the FDA, unless before that time, the FDA raises concerns or questions related to one or more proposed clinical trials and places the trial on clinical hold. In such a case, the IND sponsor and the FDA must resolve any outstanding concerns before the clinical trial can begin. As a result, submission of an IND may not result in the FDA allowing clinical trials to commence.

ii. Clinical Trials

The clinical stage of development involves the administration of the investigational product to healthy volunteers or patients under the supervision of qualified investigators, generally physicians not employed by or under the trial sponsor’s control, in accordance with GCP requirements, which include the requirement that all patients provide their informed consent for their participation in any clinical trial. Clinical trials are conducted under protocols detailing, among other things, the objectives of the clinical trial, dosing procedures, subject selection and exclusion criteria and the parameters to be used to monitor subject safety and assess efficacy. Each protocol, and any subsequent amendments to the protocol, must be submitted to the FDA as part of the IND. Furthermore, each clinical trial must be reviewed and approved by an IRB for each institution at which the clinical trial will be conducted to ensure that the risks to individuals participating in the clinical trials are minimized and are reasonable in relation to anticipated benefits. The IRB also approves the informed consent form that must be provided to each clinical trial subject or his or her legal representative, and must monitor the clinical trial until completed. There also are requirements governing the reporting of ongoing clinical trials and completed clinical trial results to public registries.

A sponsor who wishes to conduct a clinical trial outside of the U.S. may, but need not, obtain FDA authorization to conduct the clinical trial under an IND. If a foreign clinical trial is not conducted under an IND, the sponsor may submit data from the clinical trial to the FDA in support of a BLA. The FDA will accept a well-designed and well conducted foreign clinical study not conducted under an IND if the study was conducted in accordance with GCP requirements, and the FDA is able to validate the data through an onsite inspection if deemed necessary.

Clinical trials generally are conducted in three sequential phases, known as Phase 1, Phase 2 and Phase 3, and may be combined or overlap.

Post-approval trials, sometimes referred to as Phase 4 clinical trials, may be conducted after initial marketing approval. These trials are used to gain additional experience from the treatment of patients in the intended therapeutic indication. In certain instances, the FDA may mandate the performance of Phase 4 clinical trials as a condition of approval of a BLA.

Progress reports detailing the results of the clinical trials, among other information, must be submitted at least annually to the FDA and written IND safety reports must be submitted to the FDA and the investigators for suspected unexpected serious adverse reactions (“SUSARs”), findings from other studies or animal orin vitro testing that suggest a significant risk for human subjects and any clinically important increase in the rate of a serious suspected adverse reaction over that listed in the protocol or investigator brochure.

The FDA or the sponsor may suspend or terminate a clinical trial at any time on various grounds, including a finding that the patients are being exposed to an unacceptable health risk. Similarly, an IRB can suspend or terminate approval of a clinical trial at its institution if the clinical trial is not being conducted in accordance with the IRB’s requirements or if the drug or biologic has been associated with unexpected serious harm to patients. Additionally, some clinical trials are overseen by an independent group of qualified experts organized by the clinical trial sponsor, known as a data safety monitoring board (“DSMB”) or committee. The DSMB provides recommendations for whether a trial may move forward at designated check points based on access to certain data from the trial. Concurrent with clinical trials, companies usually complete additional animal studies and also must develop additional information about the chemistry and physical characteristics of the drug or biologic as well as 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 and, among other things, companies 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 candidates do not undergo unacceptable deterioration over their shelf life.

iii. FDA Review Process

Following completion of the clinical trials, data are analyzed to assess whether the investigational product is safe and effective for the proposed indicated use or uses. Chemistry, manufacturing and controls ("CMC") information, preclinical studies and clinical trials results, and proposed labeling are submitted to the FDA as part of the BLA. The BLA is a request for approval to market the biologic for one or more specified indications and must contain proof of safety, purity and potency for a biologic. The application may include both negative and ambiguous results of preclinical studies and clinical trials, as well as positive findings. Data may come from company sponsored clinical trials intended to test the safety and efficacy of a product’s use or from a number of alternative sources, including studies initiated by investigators. To support marketing approval, the data submitted must be sufficient in quality and quantity to establish the safety and efficacy of the investigational product to the satisfaction of the FDA. FDA approval of a BLA must be obtained before a biologic may be marketed in the U.S.

Under the Prescription Drug User Fee Act (“PDUFA”) as amended, each BLA must be accompanied by a user fee. The FDA adjusts the PDUFA user fees on an annual basis. Fee waivers or reductions are available in certain circumstances, including a waiver of the application fee for the first application filed by a small business. Additionally, no user fees are assessed on BLAs for products designated as orphan drugs, unless the product also includes a non-orphan indication.

The FDA reviews all submitted BLAs before it accepts them for filing, and may request additional information rather than accepting the BLA for filing. The FDA must make a decision on accepting a BLA for filing within 60 days of receipt, and such decision could include a refusal to file (“RTF”) by the FDA. Once the submission is accepted for filing, the FDA begins an in-depth review of the BLA. Under the goals and policies agreed to by the FDA under PDUFA, the FDA has 10 months, from the filing date, in which to complete its initial review of an original BLA and respond to the applicant, and six months from the filing date of an original BLA designated for priority review. The FDA does not always meet its PDUFA goal dates for standard and priority BLAs, and the review process is often extended by FDA requests for additional information or clarification.

Before approving a BLA, the FDA will conduct a preapproval inspection of the manufacturing facilities for the new product to determine whether they comply with cGMP requirements. The FDA will not approve the product unless it determines that the manufacturing processes and facilities are in compliance with cGMP requirements and adequate to assure consistent production of the product within required specifications. The FDA also may audit data from clinical trials to ensure compliance with GCP requirements. Additionally, the FDA may refer applications for novel products or products which present difficult questions of safety or efficacy to an advisory committee, typically a panel that includes clinicians and other experts, for review, evaluation and a recommendation as to whether the application should be approved and under what conditions, if any. The FDA is not bound by recommendations of an advisory committee, but it considers such recommendations when making decisions on approval. The FDA likely will reanalyze the clinical trial data, which could result in extensive discussions between the FDA and the applicant during the review process. After the FDA evaluates a BLA, it will issue an Approval Letter or a Complete Response Letter. An Approval Letter authorizes commercial marketing of the biologic with specific prescribing information for specific indications. The Approval Letter

may also include post-marketing requirements or commitments, such as the conduct of additional clinical trials or CMC studies. A Complete Response Letter indicates that the review cycle of the application is complete and the application will not be approved in its present form. A Complete Response Letter usually describes all of the specific deficiencies in the BLA identified by the FDA. The Complete Response Letter may require additional clinical data, additional pivotal Phase 3 clinical trial(s) and/or other significant and time consuming requirements related to clinical trials, preclinical studies or manufacturing. If a Complete Response Letter is issued, the applicant may either resubmit the BLA, addressing all of the deficiencies identified in the letter, or withdraw the application. Even if such data and information are submitted, the FDA may decide that the BLA does not satisfy the criteria for approval. Data obtained from clinical trials are not always conclusive and the FDA may interpret data differently than we interpret the same data.

iv. Orphan Drug Designation

Under the Orphan Drug Act, the FDA may grant orphan designation to a drug or biological product intended to treat a rare disease or condition, which is generally a disease or condition that affects fewer than 200,000 individuals in the U.S., or more than 200,000 individuals in the U.S. and for which there is no reasonable expectation that the cost of developing and making the product available in the U.S. for this type of disease or condition will be recovered from sales of the product.

After the FDA grants Orphan Drug designation, the identity of the therapeutic agent and its potential orphan use are disclosed publicly by the FDA. Orphan Drug designation does not convey any advantage in or shorten the duration of the regulatory review and approval process.

If a product that has orphan designation subsequently receives the first FDA approval 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 to market the same drug for the same indication for seven years from the date of such approval, except in limited circumstances, such as a showing of clinical superiority to the product with orphan exclusivity by means of greater effectiveness, greater safety or providing a major contribution to patient care or in instances of drug supply issues. Competitors, however, may receive approval of either a different product for the same indication or the same product for a different indication but that could be used off-label in the orphan indication. Orphan drug exclusivity also could block the approval of one of our products for seven years if a competitor obtains approval before we do for the same product, as defined by the FDA, for the same indication we are seeking approval, or if our product is determined to be contained within the scope of the competitor’s product for the same indication or disease. If a product designated as an orphan drug receives marketing approval for an indication broader than that which is designated, it may not be entitled to orphan drug exclusivity. Orphan drug status in the European Union (“EU”) has similar, but not identical, requirements and benefits.

v. Rare Pediatric Disease Designation

The FDA grants Rare Pediatric Disease designation for serious and life-threatening diseases that primarily affect children ages 18 years or younger and fewer than 200,000 individuals in the United States. Eligibility for a priority review voucher may be issued upon approval of a BLA or New Drug Application for therapies developed to treat such rare pediatric diseases. Priority review vouchers may be redeemed to obtain priority review for any subsequent marketing application or be sold or transferred. Under current statutory provisions, FDA may award a priority review voucher for an approved rare pediatric disease product application only if the sponsor has received rare pediatric disease designation for the drug by December 20, 2024, and after September 30, 2026, the FDA may not award any rare pediatric disease priority review vouchers. Congress may vote to reauthorize this program, but its future remains uncertain.

vi. Expedited Development and Review Programs

The FDA has a Fast Track program that is intended to expedite or facilitate the process for reviewing new drugs and biologics that meet certain criteria. Specifically, new drugs and biologics are eligible for Fast Track designation if they are intended to treat a serious or life-threatening condition and preclinical or clinical data demonstrate the potential to address unmet medical needs for the condition. Fast Track designation applies to both the product and the specific indication for which it is being studied. The sponsor can request the FDA to designate the product for Fast Track status

any time before receiving BLA approval, but ideally no later than the pre-BLA meeting. Any product submitted to the FDA for marketing, including under a Fast Track program, may be eligible for other types of FDA programs intended to expedite development and review, such as priority review and accelerated approval. Any product is eligible for priority review if it treats a serious or life-threatening condition and, if approved, would provide a significant improvement in safety and effectiveness compared to available therapies. The FDA will attempt to direct additional resources to the evaluation of an application for a new drug or biologic designated for priority review in an effort to facilitate the review.

A product may also be eligible for accelerated approval, if it treats a serious or life-threatening condition and generally provides a meaningful advantage over available therapies. Accelerated approval may also be granted in the case that there are no alternative treatments available. In addition, it must demonstrate 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 (“IMM”), that is reasonably likely to predict an effect on IMM or other clinical benefit. As a condition of approval, the FDA may require that a sponsor of a drug or biologic receiving accelerated approval perform adequate and well-controlled post-marketing clinical trials with due diligence and, under the Food and Drug Omnibus Reform Act of 2022 (“FDORA”), the FDA is now permitted to require that such trials be underway prior to approval or within a specific time period after, the date accelerated approval is granted. In addition, for products being considered for accelerated approval, the FDA currently requires, unless otherwise informed by the agency, that all advertising and promotional materials intended for dissemination or publication within 120 days of marketing approval be submitted to the agency for review during the pre-approval review period. If the FDA concludes that a drug or biologic shown to be effective can be safely used only if distribution or use is restricted, it will require such post-marketing restrictions, as it deems necessary to assure safe use of the product. Under FDORA, the FDA has increased authority for expedited procedures to withdraw approval of a product or indication approved under accelerated approval if, for example, the confirmatory trial fails to verify the predicted clinical benefit of the product.

Additionally, a drug or biologic may be eligible for designation as a breakthrough therapy if the product is intended, alone or in combination with one or more other drugs or biologics, to treat a serious or life-threatening condition and preliminary clinical evidence indicates that the product may demonstrate substantial improvement over currently approved therapies on one or more clinically significant endpoints. The benefits of breakthrough therapy designation include the same benefits as Fast Track designation, plus intensive guidance from the FDA to ensure an efficient drug development program.

Fast Track designation, priority review, accelerated approval and breakthrough therapy designation do not change the standards for approval, but may expedite the development or approval process.

vii. Pediatric Information

Under the Pediatric Research Equity Act (“PREA”), as amended, a BLA or supplement to a BLA must contain data to assess the safety and efficacy of the drug for the claimed indications in all relevant pediatric subpopulations and to support dosing and administration for each pediatric subpopulation for which the product is safe and effective. The FDA may grant deferrals for submission of pediatric data or full or partial waivers. Unless otherwise required by regulation, PREA does not apply to any biological product for an indication for which orphan designation has been granted. A sponsor who is planning to submit a marketing application for a drug that includes a new active ingredient, new indication, new dosage form, new dosing regimen or new route of administration submits an initial Pediatric Study Plan (“PSP”) within 60 days of an end-of-Phase 2 meeting or, if there is no such meeting, as early as practicable before the initiation of the Phase 3 or Phase 2/3 study. The initial PSP must include an outline of the pediatric study or studies that the sponsor plans to conduct, including study objectives and design, age groups, relevant endpoints and statistical approach, or a justification for not including such detailed information, and any request for a deferral of pediatric assessments or a full or partial waiver of the requirement to provide data from pediatric studies along with supporting information. The FDA and the sponsor must reach an agreement on the PSP. A sponsor can submit amendments to an agreed-upon initial PSP at any time if changes to the pediatric plan need to be considered based on data collected from preclinical studies, early phase clinical trials and/or other clinical development programs.

viii. Post-marketing Requirements

Following approval of a new product, the manufacturer and the approved product are subject to continuing regulation by the FDA, including, among other things, monitoring and record-keeping activities, reporting of adverse experiences,

complying with promotion and advertising requirements, which include restrictions on promoting products for unapproved uses or patient populations (known as “off-label use”) and limitations on industry-sponsored scientific and educational activities. Although physicians may prescribe legally available products for off-label uses, manufacturers may not market or promote such uses. Prescription drug and biologic promotional materials must be submitted to the FDA in conjunction with their first use. Further, if there are any modifications to the drug or biologic, including changes in indications, labeling or manufacturing processes or facilities, the applicant may be required to submit and obtain FDA approval of a new BLA or BLA supplement, which may require the development of additional data or preclinical studies and clinical trials.

The FDA may also place other conditions on approvals including the requirement for a Risk Evaluation and Mitigation Strategy (“REMS”) to assure the safe use of the product. If the FDA concludes a REMS is needed, the sponsor of the BLA must submit a proposed REMS. The FDA will not approve the BLA without an approved REMS, if required. A REMS 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. Any of these limitations on approval or marketing could restrict the commercial promotion, distribution, prescription or dispensing of products. Newly discovered or developed safety or effectiveness data may require changes to a drug’s approved labeling, including the addition of new warnings and contraindications, and also may require the implementation of other risk management measures, including a REMS or the conduct of post-marketing studies to assess a newly discovered safety issue. Product approvals may be withdrawn for non-compliance with regulatory standards or if problems occur following initial marketing.

FDA regulations require that products be manufactured in specific approved facilities and in accordance with cGMP regulations. These manufacturers must comply with cGMP regulations that require, among other things, quality control and quality assurance, the maintenance of records and documentation and the obligation to investigate and correct any deviations from cGMP. Manufacturers and other entities involved in the manufacture and distribution of approved drugs or biologics 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 requirements and other laws, as well as applicable tracking and tracing requirements. Accordingly, manufacturers must continue to expend time, money and effort in the area of production and quality control to maintain cGMP compliance. The discovery of violative conditions, including failure to conform to cGMP regulations, could result in enforcement actions, and the discovery of problems with a product after approval may result in restrictions on a product, manufacturer or holder of an approved BLA, including recall.

ix. Other Regulatory Matters

Manufacturing, sales, promotion and other activities following product approval are also subject to regulation by numerous regulatory authorities in the U.S. in addition to the FDA, including the Centers for Medicare & Medicaid Services (“CMS”), other divisions of the Department of Health and Human Services (“HHS”), the Department of Justice, the Consumer Product Safety Commission, the Federal Trade Commission, the Occupational Safety & Health Administration, the Environmental Protection Agency and state and local governments.

x. Other Healthcare and Privacy Laws

Healthcare providers, physicians, and third-party payors will play a primary role in the recommendation and prescription of any products for which we obtain marketing approval. Our future arrangements with third-party payors, healthcare providers and physicians may expose us to broadly applicable fraud and abuse and other healthcare laws and regulations that may constrain the business or financial arrangements and relationships through which we market, sell and distribute any drugs for which we obtain marketing approval. In particular, the research of our product candidates, as well as the promotion, sales and marketing of healthcare items and services, as well as certain business arrangements in the healthcare industry, are subject to extensive laws designed to prevent fraud, kickbacks, self-dealing and other abusive practices. These laws and regulations may restrict or prohibit a wide range of pricing, discounting, marketing and promotion, structuring and commission(s), certain customer incentive programs and other business arrangements generally. Activities subject to these laws also involve the improper use of information obtained in the course of patient recruitment for clinical trials. In the U.S., these laws include, without limitation, state and federal anti-kickback, false

claims, physician transparency, and patient data privacy and security laws and regulations, including but not limited to those described below.

Similar comprehensive privacy laws have been passed in numerous other states and other states have proposed similar new privacy laws. Such proposed legislation, if enacted, may add additional complexity, variation in requirements, restrictions and potential legal risk, require additional investment of resources in compliance programs, impact strategies and the availability of previously useful data and could result in increased compliance costs and/or changes in business practices and policies. The existence of comprehensive privacy laws in different states in the country would make our compliance obligations more complex and costly and may increase the likelihood that we may be subject to enforcement actions or otherwise incur liability for noncompliance. There are also states that are specifically regulating health information. For example, Washington state recently passed a health privacy law that will regulate the collection and sharing of health information, and the law also has a private right of action, which further increases the relevant compliance risk. Connecticut and Nevada have also passed similar laws regulating consumer health data. In addition, other states have proposed and/or passed legislation that regulates the privacy and/or security of certain specific types of information. For example, a small number of states have passed laws that regulate biometric data specifically. These various privacy and security laws may impact our business activities, including our identification of research subjects, relationships with business partners and ultimately the marketing and distribution of our products. State laws are changing rapidly and there is discussion in the U.S. Congress of a new comprehensive federal data privacy law to which we may likely become subject, if enacted.

All of these evolving compliance and operational requirements impose significant costs, such as costs related to organizational changes, implementing additional protection technologies, training employees and engaging consultants and legal advisors, which are likely to increase over time. In addition, such requirements may require us to modify our data processing practices and policies, utilize management’s time and/or divert resources from other initiatives and projects. Any failure or perceived failure by us to comply with any applicable federal, state or foreign laws and

regulations relating to data privacy and security could result in damage to our reputation, as well as proceedings or litigation by governmental agencies or other third parties, including class action privacy litigation in certain jurisdictions, which would subject us to significant fines, sanctions, awards, injunctions, penalties or judgments. Any of the foregoing could have a material adverse effect on our business, financial condition, results of operations and prospects.

The scope and enforcement of each of these laws is uncertain and subject to rapid change in the current environment of healthcare reform, especially in light of the lack of applicable precedent and regulations. Federal and state enforcement bodies have recently increased their scrutiny of interactions between healthcare companies and healthcare providers, which has led to a number of investigations, prosecutions, convictions and settlements in the healthcare industry. It is possible that governmental authorities will conclude that our business practices do not comply with current or future statutes, regulations or case law involving applicable fraud and abuse or other healthcare laws and regulations. If our operations are found to be in violation of any of these laws or any other related governmental regulations that may apply to us, we may be subject to significant civil, criminal and administrative penalties, damages, fines, individual imprisonment, disgorgement, exclusion of drugs from participation in state and federal healthcare programs, such as Medicare and Medicaid, reputational harm, additional oversight and reporting obligations if we become subject to a corporate integrity agreement or similar settlement to resolve allegations of non-compliance with these laws and the curtailment or restructuring of our operations. If any of the physicians or other healthcare providers or entities with whom we expect to do business is found to be not in compliance with applicable laws, they may be subject to similar actions, penalties and sanctions. Ensuring business arrangements comply with applicable healthcare laws, as well as responding to possible investigations by government authorities, can be time and resource consuming and can divert a company’s attention from the business.

xi. Current and Future Healthcare Reform Legislation

In the U.S. and foreign jurisdictions, there have been a number of legislative and regulatory changes and proposed changes regarding the healthcare system that could prevent or delay marketing approval of our product candidates, restrict or regulate post-approval activities and affect our ability to profitably sell any product candidates for which we obtain marketing approval. We expect that current laws, as well as other healthcare reform measures that may be adopted in the future, may result in more rigorous coverage criteria and in additional downward pressure on the price that we, or any collaborators, may receive for any approved products.

In the U.S., for example, in March 2010, the ACA was enacted. The ACA included provisions that address pharmaceutical pricing. Among other things, for example, the FDA:

Some of the provisions of the ACA have been subject to judicial challenges as well as efforts to repeal, replace or otherwise modify them or to alter their interpretation or implementation. For example:

Although a number of these and other proposed measures may require authorization through additional legislation to become effective, and the Trump administration may reverse or otherwise change these measures, both the Trump administration and Congress have indicated that they will continue to seek new legislative measures to control drug costs.

Individual states in the United States have also increasingly passed legislation and implemented regulations designed to control pharmaceutical product pricing, including by imposing price or patient assistance constraints, restrictions on certain product access, marketing cost disclosure and other transparency measures, and, in some cases, measures designed to encourage importation of pharmaceutical products from other countries and bulk purchasing.

xii. Packaging and Distribution in the U.S.

If our products are made available to authorized users of the Federal Supply Schedule of the General Services Administration, additional laws and requirements apply. Products must meet applicable child resistant packaging requirements under the U.S. Poison Prevention Packaging Act. Manufacturing, sales, promotion and other activities also are potentially subject to federal and state consumer protection and unfair competition laws.

The distribution of pharmaceutical products is subject to additional requirements and regulations, including extensive record keeping, licensing, storage and security requirements intended to prevent the unauthorized sale of pharmaceutical products.

The failure to comply with any of these laws or regulatory requirements subjects firms to possible legal or regulatory action. Depending on the circumstances, failure to meet applicable regulatory requirements can result in criminal prosecution, fines or other penalties, injunctions, exclusion from federal healthcare programs, requests for recall, seizure of products, total or partial suspension of production, denial or withdrawal of product approvals, or refusal to allow a firm to enter into supply contracts, including government contracts.

Changes in regulations, statutes or the interpretation of existing regulations could impact our business in the future by requiring, for example: (i) changes to our manufacturing arrangements; (ii) additions or modifications to product labeling; (iii) the recall or discontinuation of our products; or (iv) additional record keeping requirements.

xiii. Other U.S. Environmental, Health and Safety Laws and Regulations

We may be subject to numerous environmental, health and safety laws and regulations, including those governing laboratory procedures and the handling, use, storage, treatment and disposal of hazardous materials and wastes. From time to time and in the future, our operations may involve the use of hazardous and flammable materials, including chemicals and biological materials, and may also produce hazardous waste products. Even if we contract with third parties for the disposal of these materials and waste products, we cannot completely eliminate the risk of contamination or injury resulting from these materials. In the event of contamination or injury resulting from the use or disposal of our hazardous materials, we could be held liable for any resulting damages, and any liability could exceed our resources. We also could incur significant costs associated with civil or criminal fines and penalties for failure to comply with such laws and regulations.

We maintain workers’ compensation insurance to cover us for costs and expenses we may incur due to injuries to our employees, but this insurance may not provide adequate coverage against potential liabilities. However, we do not maintain insurance for environmental liability or toxic tort claims that may be asserted against us.

xiv. U.S. Patent Term Restoration and Marketing Exclusivity

Depending upon the timing, duration and specifics of FDA approval of our current product candidates and any future product candidates, some of our U.S. patents may be eligible for limited patent term extension under the Drug Price Competition and Patent Term Restoration Act of 1984, commonly referred to as the Hatch Waxman Amendments. The Hatch Waxman Amendments permit restoration of the patent term of up to five years as compensation for patent term lost during product development and FDA regulatory review process. Patent term restoration, however, cannot extend the remaining term of a patent beyond a total of 14 years from the product’s approval date. The patent term restoration period is generally one half the time between the effective date of an IND and the submission date of a BLA plus the time between the submission date of a BLA and the approval of that application, except that the review period is reduced by any time during which the applicant failed to exercise due diligence. Only one patent applicable to an approved drug is eligible for the extension and the application for the extension must be submitted prior to the expiration of the patent. The U.S. PTO, in consultation with the FDA, reviews and approves the application for any patent term extension or restoration. In the future, we may apply for restoration of patent term for our currently owned or licensed patents to add patent life beyond its current expiration date, depending on the expected length of the clinical trials and other factors involved in the filing of the relevant BLA.

An abbreviated approval pathway for biological products shown to be biosimilar to, or interchangeable with, an FDA licensed reference biological product was created by the Biologics Price Competition and Innovation Act of 2009 (“BPCI Act”). This amendment to the PHSA, in part, attempts to minimize duplicative testing. Biosimilarity, which requires that the biological product be highly similar to the reference product notwithstanding minor differences in clinically inactive components and that there be no clinically meaningful differences between the product and the reference product in terms of safety, purity and potency, can be shown through analytical studies, animal studies and a clinical trial or trials. Interchangeability requires that a biological product be biosimilar to the reference product and that the product can be expected to produce the same clinical results as the reference product in any given patient and, for products administered multiple times to an individual, that the product and the reference product 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 biological product without such alternation or switch.

A reference biological product is granted 12 years of data exclusivity from the time of first licensure of the product, and the FDA will not accept an application for a biosimilar or interchangeable product based on the reference biological product until four years after the date of first licensure of the reference product. “First licensure” typically means the initial date the particular product at issue was licensed in the U.S. Date of first licensure does not include the date of licensure of (and a new period of exclusivity is not available for) a biological product if the licensure is for a supplement for the biological product or for a subsequent application by the same sponsor or manufacturer of the biological product (or licensor, predecessor in interest, or other related entity) for a change (not including a modification to the structure of the biological product) that results in a new indication, route of administration, dosing schedule, dosage form, delivery system, delivery device or strength, or for a modification to the structure of the biological product that does not result in a change in safety, purity, or potency. The first biological product determined to be interchangeable with a reference product for any condition of use is also eligible for a period of exclusivity during which time the FDA may not determine that another product is interchangeable with the same reference product for any condition of use. The FDA may approve multiple “first” interchangeable products so long as they are all approved on the same first day of marketing.

Pediatric exclusivity is another type of regulatory market exclusivity in the U.S. Pediatric exclusivity, if granted, adds six months to existing regulatory exclusivity periods for all formulations, dosage forms, and indications of the biologic. This six-month exclusivity may be granted based on the voluntary completion of a pediatric trial that fairly responds to an FDA issued “Written Request” for such a trial.

b. European Union Drug Development

In the EU, our future products also may be subject to extensive regulatory requirements. As in the U.S., medicinal products can be marketed only if a marketing authorization from the competent regulatory agencies has been obtained.

Similar to the U.S., the various phases of preclinical and clinical research in the EU are subject to significant regulatory controls.

In April 2014, the EU adopted the Clinical Trials Regulation EU No 536/2014, which replaced the Clinical Trials Directive 2001/20/EC on January 31, 2022. The main characteristics of the Clinical Trials Regulation include: a streamlined application procedure via a single-entry point through the Clinical Trials Information System (“CTIS”); a single set of documents to be prepared and submitted for the application as well as simplified reporting procedures for clinical trial sponsors; and a harmonized procedure for the assessment of applications for clinical trials, which is divided into two parts (Part I contains scientific and medicinal product documentation and Part II contains the national and patient-level documentation). Part I is assessed by a coordinated review by the competent authorities of all EU Member States in which an application for authorization of a clinical trial has been submitted (Member States concerned) of a draft report prepared by a Reference Member State. Part II is assessed separately by each Member State concerned. Strict deadlines have been established for the assessment of clinical trial applications. The role of the relevant ethics committees in the assessment procedure will continue to be governed by the national law of the concerned EU Member State. However, overall related timelines will be defined by the Clinical Trials Regulation. The transitory provisions of the Clinical Trial Regulation provide that, by January 31, 2025, all ongoing clinical trials must have transitioned to the Clinical Trials Regulation.

In the EU the Paediatric Committee (“PDCO”) of the EMA must approve a pediatric investigation plan (“PIP”) prior to an applicant filing a marketing authorization application (“MAA”), unless the EMA has granted a product-specific waiver or a class waiver. The PIP outlines the pharmaceutical company’s strategy for investigation of the new medicinal product in the pediatric population. Before an MAA can be filed, or an existing marketing authorization can be amended, the EMA determines whether companies actually comply with the agreed studies and measures listed in each relevant PIP. If an applicant obtains a marketing authorization in all EU Member States, or a marketing authorization granted in the centralized procedure by the EC, and the study results for the pediatric population are included in the product information, even when negative, the medicine is then eligible for an additional six-month period of qualifying patent protection through extension of the term of any supplementary protection certificate (“SPC”), provided an application for such extension is made at the same time as filing the SPC application for the product, or at any point up to 2 years before the SPC expires. The incentive in the case of orphan medicinal products is that a two-year extension of the orphan market exclusivity may be available. This pediatric reward is subject to specific conditions and is not automatically available when data in compliance with the PIP are developed and submitted.

i. European Union Expedited Review and Development

PRIME is a scheme provided by the EMA to enhance support for the development of medicines that target an unmet medical need and provides accelerated assessment of products representing substantial innovation where the MAA will be made through the centralized procedure. To qualify for PRIME, product candidates require early clinical evidence that the therapy has the potential to offer a major therapeutic advantage over existing treatments or benefits patients without treatment options. Products from small-and medium-sized enterprises (“SMEs”) may qualify for earlier entry into the PRIME scheme than larger companies. Among the benefits of PRIME are the appointment of a rapporteur to provide continuous support and help build knowledge ahead of an MAA, early dialogue and scientific advice at key development milestones, and the potential to qualify products for accelerated review earlier in the application process. The receipt of PRIME designation does not change the standards for approval but may expedite the development or approval process. Where, during the course of development, a product no longer meets the eligibility criteria, support under the PRIME scheme may be withdrawn.

ii. European Union Drug Marketing

Much like the Anti-Kickback Statute prohibition in the U.S., the provision of benefits or advantages to physicians to induce or encourage the prescription, recommendation, endorsement, purchase, supply, order or use of medicinal products is also prohibited in the EU. The provision of benefits or advantages to physicians to induce or reward improper performance generally is typically governed by the national anti-bribery laws of EU Member States, and the Bribery Act 2010 in the UK. Infringement of these laws could result in substantial fines and imprisonment. EU Directive 2001/83/EC, which is the EU Directive governing medicinal products for human use, further provides that, where medicinal products are being promoted to persons qualified to prescribe or supply them, no gifts, pecuniary advantages or benefits in kind may be supplied, offered or promised to such persons unless they are inexpensive and relevant to the practice of medicine or pharmacy. This provision has been transposed into the Human Medicines Regulations 2012 and so remains applicable in the UK despite its departure from the EU.

Payments made to physicians in certain EU Member States must be publicly disclosed. Moreover, agreements with physicians often must be the subject of prior notification and approval by the physician’s employer, his or her competent professional organization and/or the regulatory authorities of the individual EU Member States. These requirements are provided in the national laws, industry codes or professional codes of conduct, applicable in the EU Member States. Failure to comply with these requirements could result in reputational risk, public reprimands, administrative penalties, fines or imprisonment.

iii. European Union Drug Review and Approval

In the EU, medicinal products can only be commercialized after obtaining a marketing authorization (“MA”). There are two types of MAs.

Centralized MAs, which are issued by the EC through the centralized procedure, based on the opinion of the Committee for Medicinal Products for Human Use (“CHMP”) of the EMA, are valid throughout the EU, and in the additional Member States of the European Economic Area (“EEA”) (Iceland, Liechtenstein and Norway). The centralized procedure is mandatory for certain types of products, such as medicinal products produced by certain biotechnological processes, products designated as orphan medicinal products, advanced therapy medicinal products (i.e., gene therapy, somatic cell therapy or tissue engineered medicines) and medicinal products containing a new active substance indicated for the treatment of HIV, AIDS, cancer, neurodegenerative disorders, diabetes, autoimmune and other immune dysfunctions and viral diseases. The centralized procedure is optional for products containing a new active substance not yet authorized in the EU, or for products that constitute a significant therapeutic, scientific or technical innovation or which are in the interest of public health in the EU.

National MAs, which are issued by the competent authorities of the EU Member States and only cover their respective territory, are available for products not falling within the mandatory scope of the centralized procedure. Where a product has already been authorized for marketing in an EU Member State, this national MA can be recognized in another EU Member State through the mutual recognition procedure. If the product has not received a national MA in any EU Member State at the time of application, it can be approved simultaneously in various EU Member States through the

decentralized procedure. Under the decentralized procedure an identical dossier is submitted to the competent authorities of each of the EU Member States in which the MA is sought, one of which is selected by the applicant as the reference Member State (“RMS”). The competent authority of the RMS prepares a draft assessment report, a draft summary of the product characteristics (“SmPC”), and a draft of the labeling and package leaflet, which are sent to the other Member States (referred to as the Member States Concerned) for their approval. If the Member States Concerned raise no objections, based on a potential serious risk to public health, to the assessment, SmPC, labeling, or packaging proposed by the RMS, the product is subsequently granted a national MA in all the Member States involved (i.e., in the RMS and the Member States Concerned).

Under the above described procedures, before granting the MA, the EMA or the competent authorities of the EU Member States make an assessment of the risk benefit balance of the product on the basis of scientific criteria concerning its quality, safety and efficacy.

iv. European Union Data and Market Exclusivity

In the EU, innovative products authorized for marketing (i.e., reference products) qualify for eight years of data exclusivity and an additional two years of market exclusivity upon marketing authorization. The data exclusivity, if granted, prevents applicants for authorization of generics or biosimilars of these innovative products from referencing the innovator’s preclinical and clinical trial data contained in the dossier of the reference product when applying for a generic or biosimilar MA in the EU, during a period of eight years from the date on which the reference product was first authorized in the EU. During an additional two-year period of market exclusivity, a generic or biosimilar MAA can be submitted, and the innovator’s data may be referenced, but no generic or biosimilar medicinal product can be placed on the EU market until the expiration of the market exclusivity. The overall 10-year period will be extended to a maximum of 11 years if, during the first eight years of those 10 years, the marketing authorization holder obtains an authorization for one or more new therapeutic indications which, during the scientific evaluation prior to their authorization, are determined to bring a significant clinical benefit in comparison with currently approved therapies. There is no guarantee that a product will be considered by the EMA to be an innovative medicinal product, and products may not qualify for data exclusivity. Even if a product is considered to be an innovative medicinal product so that the innovator gains the prescribed period of data exclusivity, another company nevertheless could also market another version of the product if such company obtained an MA based on an MAA with a complete and independent data package of pharmaceutical tests, preclinical tests and clinical trials.

v. European Union Orphan Designation and Exclusivity

In the EU, after a recommendation from the EMA’s Committee for Orphan Medicinal Products (“COMP”), the European Commission may grant orphan designation to a product if (1) the product is intended for the diagnosis, prevention or treatment of a life-threatening or chronically debilitating condition; (2) either (a) such condition affects no more than five in 10,000 persons in the EU when the application is made, or (b) it is unlikely that the product, without the benefits derived from orphan status, would generate sufficient return in the EU to justify the necessary investment in its development; and (3) there exists no satisfactory method of diagnosis, prevention or treatment of such condition authorized for marketing in the EU or, if a method exists, the product would be a significant benefit to those affected by that condition.

In the EU, orphan designation entitles a party to financial incentives such as reduction of fees or fee waivers and 10 years of market exclusivity is granted following medicinal product approval during which time no “similar medicinal product” may be placed on the market. A “similar medicinal product” is defined as a medicinal product containing a similar active substance or substances as contained in an authorized orphan medicinal product, and which is intended for the same therapeutic indication. This period may be reduced to six years if, at the end of the fifth year, it is determined that the orphan designation criteria are no longer met, including where it is shown that the product is sufficiently profitable so as not to justify maintenance of market exclusivity. Orphan designation must be requested before submitting an application for an MA. We will be required to apply for the maintenance of the orphan designation granted to apitegromab for the treatment of SMA at the time of applying for an MA. Orphan designation does not convey any advantage in, or shorten the duration of, the regulatory review and approval process.

The aforementioned EU rules are generally applicable in the EEA.

vi. Reform of the Regulatory Framework in the European Union

The European Commission introduced legislative proposals in April 2023 that, if implemented, will replace the current regulatory framework in the EU for all medicines (including those for rare diseases and for children). The European Commission has provided the legislative proposals to the European Parliament and the European Council for their review and approval, and in April 2024, the European Parliament proposed amendments to the legislative proposals. Once the European Commission’s legislative proposals are approved (with or without amendment), they will be adopted into EU law.

vii. European General Data Protection Regulation

Since we conduct clinical trials in the EEA, we are subject to additional European data privacy laws. The General Data Protection Regulation, (EU) 2016/679 (“GDPR”), became effective on May 25, 2018, and deals with the processing of personal data and on the free movement of such data. The GDPR imposes a broad range of strict requirements on companies subject to the GDPR, including requirements relating to having legal bases for processing personal data (such as health and other sensitive data,) relating to identifiable individuals and transferring such information outside the EEA, including to the U.S., providing details to those individuals regarding the processing of their personal information, keeping personal information secure, obtaining consent of the individuals to whom the personal data relates, having data processing agreements with third parties who process personal information, responding to individuals’ requests to exercise their rights in respect of their personal information, reporting security breaches involving personal data to the competent national data protection authority and affected individuals, appointing data protection officers, conducting data protection impact assessments, and record-keeping. The GDPR increases substantially the penalties to which we could be subject in the event of any non-compliance, including fines of up to 10,000,000 Euros or up to 2% of our total worldwide annual turnover for certain comparatively minor offenses, or up to 20,000,000 Euros or up to 4% of our total worldwide annual turnover for more serious offenses, whichever is greater. The GDPR also confers a private right of action on data subjects and consumer associations to lodge complaints with supervisory authorities, seek judicial remedies, and obtain compensation for damages resulting from violations of the GDPR. In addition, the GDPR includes restrictions on cross-border data transfers. The GDPR may increase our responsibility and liability in relation to personal data that we process where such processing is subject to the GDPR, and we may be required to put in place additional mechanisms to ensure compliance with the GDPR, including as implemented by individual countries. Given the limited enforcement of the GDPR to date, we face uncertainty as to the exact interpretation of the new requirements on our trials and we may be unsuccessful in implementing all measures required by data protection authorities or courts in interpretation of the new law. Compliance with the GDPR will be a rigorous and time-intensive process that may increase our cost of doing business or require us to change our business practices, and despite those efforts, there is a risk that we may be subject to fines and penalties, litigation, and reputational harm in connection with our European activities.

National laws of member states of the EU are in the process of being adapted to the requirements under the GDPR, thereby implementing national laws which may partially deviate from the GDPR and impose different obligations from country to country, so that we do not expect to operate in a uniform legal landscape in the EEA. Also, as it relates to processing and transfer of genetic data, the GDPR specifically allows national laws to impose additional and more specific requirements or restrictions, and European laws have historically differed quite substantially in this field, leading to additional uncertainty. In addition, further to the UK’s exit from the EU on January 31, 2020, the GDPR ceased to apply in the UK at the end of the transition period on December 31, 2020. However, as of January 1, 2021, the UK’s European Union (Withdrawal) Act 2018 incorporated the GDPR (as it existed on December 31, 2020 but subject to certain UK specific amendments) into UK law, referred to as the UK GDPR. The UK GDPR and the UK Data Protection Act 2018 set out the UK’s data protection regime, which is independent from but aligned to the EU’s data protection regime. The UK has announced plans to reform the country’s data protection legal framework in its Data Reform Bill, but these have been put on hold. Non-compliance with the UK GDPR may result in monetary penalties of up to £17.5 million or 4% of worldwide revenue, whichever is higher. Although the UK is regarded as a third country under the EU’s GDPR, the EC has now issued a decision recognizing the UK as providing adequate protection under the EU GDPR and, therefore, transfers of personal data originating in the EU to the UK remain unrestricted. Like the EU GDPR, the UK GDPR restricts personal data transfers outside the UK to countries not regarded by the UK as providing adequate protection. The UK government has confirmed that personal data transfers from the UK to the EEA remain free flowing.

In the event we continue to conduct clinical trials in the EEA, we must also ensure that we maintain adequate safeguards to enable the transfer of personal data outside of the EEA, in particular to the U.S., in compliance with European data protection laws. In the past, companies in the U.S. were able to rely upon the EU-U.S. Privacy Shield framework to

legitimize data transfers from the EU the U.S. In July 2020, the Court of Justice of the European Union (“CJEU”) in Case C-311/18 (Data Protection Commissioner v Facebook Ireland and Maximillian Schrems [“Schrems II”]) invalidated the EU-U.S. Privacy Shield on the grounds that the Privacy Shield failed to offer adequate protections to EU personal data transferred to the U.S. The CJEU, in the same decision, deemed that the Standard Contractual Clauses (“SCCs”) published by the EC are valid. However, the CJEU ruled that transfers made pursuant to the SCCs need to be assessed on a case-by-case basis to ensure the law in the recipient country provides “essentially equivalent” protections to safeguard the transferred personal data as the EU, and required businesses to adopt supplementary measures if such standard is not met. Subsequent guidance published by the European Data Protection Board in June 2021 described what such supplementary measures must be, and stated that businesses should avoid or cease transfers of personal data if, in the absence of supplementary measures, equivalent protections cannot be afforded. On June 4, 2021, the EC issued new forms of standard contractual clauses for data transfers from controllers or processors in the EU/EEA (or otherwise subject to the GDPR) to controllers or processors established outside the EU/EEA (and not subject to the GDPR). The new standard contractual clauses replace the standard contractual clauses that were adopted previously under the EU Data Protection Directive. The UK is not subject to the EC’s new standard contractual clauses but has published a draft version of a UK-specific transfer mechanism, which, once finalized, will enable transfers from the UK. We will be required to implement these new safeguards when conducting restricted data transfers under the EU and UK GDPR and doing so will require significant effort and cost. On March 25, 2022, the EC and the U.S. announced to have reached a political agreement on a new “Trans-Atlantic Data Privacy Framework”, which will replace the invalidated Privacy Shield and on December 13, 2022, the EC published a draft adequacy decision on the Trans-Atlantic Data Privacy Framework.

c. Regulation in the United Kingdom

The UK formally left the EU on January 31, 2020. The EU and the UK have concluded a trade and cooperation agreement (“TCA”), which was provisionally applicable since January 1, 2021 and has been formally applicable since May 1, 2021. The TCA includes specific provisions concerning pharmaceuticals, which include the mutual recognition of GMP, inspections of manufacturing facilities for medicinal products and GMP documents issued, but does not provide for wholesale mutual recognition of UK and EU pharmaceutical regulations. At present, the UK has implemented EU legislation on the marketing, promotion and sale of medicinal products through the Human Medicines Regulations 2012 (as amended). The regulatory regime in the UK therefore currently aligns in many respects with EU medicines regulations, however it is possible that these regimes will diverge in the future now that the UK’s regulatory system is independent from the EU and the TCA does not provide for mutual recognition of UK and EU pharmaceutical legislation. Notwithstanding that there is no wholesale recognition of EU pharmaceutical legislation under the TCA, under a new international recognition procedure which was put in place by the Medicines and Healthcare products Regulatory Agency (“MHRA”), the UK medicines regulator, on January 1, 2024, the MHRA may take into account decisions on the approval of an MA from the EMA (and certain other regulators) when considering an application for a UK MA.

On February 27, 2023, the UK government and the European Commission announced a political agreement in principle to replace the Northern Ireland Protocol with a new set of arrangements, known as the “Windsor Framework”. The Windsor Framework was approved by the EU-UK Joint Committee on March 24, 2023, and the medicines aspects of the Windsor Framework have applied since January 1, 2025. This new framework fundamentally changes the previous system under the Northern Ireland Protocol, including with respect to the regulation of medicinal products in the UK. In particular, the MHRA is now responsible for approving all medicinal products destined for the UK market (i.e., Great Britain and Northern Ireland), and the EMA no longer has any role in approving medicinal products destined for Northern Ireland under the EU centralized procedure. A single UK-wide MA will be granted by the MHRA for all novel medicinal products to be sold in the UK, enabling products to be sold in a single pack and under a single authorization throughout the UK. In addition, the new arrangements require all medicines placed on the UK market to be labelled “UK only”, indicating they are not for sale in the EU.

i. Clinical Trials

The UK has implemented the now repealed Clinical Trials Directive 2001/20/EC into national law through the Medicines for Human Use (Clinical Trials) Regulations 2004 (as amended). However, on December 12, 2024, the UK government introduced a legislative proposal—the Medicines for Human Use (Clinical Trials) (Amendment) Regulations 2024—that, if implemented, will replace the current regulatory framework for clinical trials in the UK. The legislative proposal aims to provide a more flexible regime to make it easier to conduct clinical trials in the UK and

increase the transparency of clinical trials conducted in the UK. This includes a notification scheme to enable lower-risk clinical trials to be automatically approved by the MHRA, where the risk is similar to that of standard medical care (although such trials would still require ethics committee approval). Such Regulations are expected to come into force in early 2026.

ii. Orphan Designation

A separate process for orphan designation to the EU process now applies in the UK. There is no pre-marketing authorization orphan designation (as there is in the EU) in the UK and the application for orphan designation will be reviewed by the MHRA at the time of an application for a UK MA. The criteria for orphan designation remain the same as in the EU, except that they apply to the UK only (e.g., there must be no satisfactory method of diagnosis, prevention or treatment of the condition in the UK, as opposed to the EU).

d. Rest of the World Regulation

For other countries outside of the UK, the EU and the U.S., such as countries in Eastern Europe, Latin America or Asia, the requirements governing the conduct of clinical trials, product licensing, pricing and reimbursement vary from country to country. Additionally, the clinical trials must be conducted in accordance with GCP requirements and the applicable regulatory requirements and the ethical principles that have their origin in the Declaration of Helsinki.

e. Additional Laws and Regulations Governing International Operations

If we further expand our operations outside of the U.S., we must dedicate additional resources to comply with numerous laws and regulations in each jurisdiction in which we plan to operate. The Foreign Corrupt Practices Act (“FCPA”) prohibits any U.S. individual or business from paying, offering, authorizing payment or offering of anything of value, directly or indirectly, to any foreign official, political party or candidate for the purpose of influencing any act or decision of the foreign entity in order to assist the individual or business in obtaining or retaining business. The FCPA also obligates companies whose securities are listed in the U.S. to comply with certain accounting provisions requiring the company to maintain books and records that accurately and fairly reflect all transactions of the corporation, including international subsidiaries, and to devise and maintain an adequate system of internal accounting controls for international operations.

Compliance with the FCPA is expensive and difficult, particularly in countries in which corruption is a recognized problem. In addition, the FCPA presents particular challenges in the pharmaceutical industry, because, in many countries, hospitals are operated by the government, and doctors and other hospital employees are considered foreign officials. Certain payments to hospitals in connection with clinical trials and other work have been deemed to be improper payments to government officials and have led to FCPA enforcement actions.

Various laws, regulations and executive orders also restrict the use and dissemination outside of the U.S., or the sharing with certain non-U.S. nationals, of information classified for national security purposes, as well as certain products and technical data relating to those products. If we expand our presence outside of the U.S., it will require us to dedicate additional resources to comply with these laws, and these laws may preclude us from developing, manufacturing, or selling certain products and product candidates outside of the U.S., which could limit our growth potential and increase our development costs.

The failure to comply with laws governing international business practices may result in substantial civil and criminal penalties and suspension or debarment from government contracting. The U.S. Securities and Exchange Commission (“SEC”) also may suspend or bar issuers from trading securities on U.S. exchanges for violations of the FCPA’s accounting provisions.

Government authorities and other third-party payors, such as private health insurers and health maintenance organizations, decide which drugs and treatments they will cover and the amount of reimbursement. In the United States, the principal decisions about reimbursement for new medicines are typically made by CMS, an agency within the U.S.

Department of Health and Human Services. CMS decides whether and to what extent a new medicine will be covered and reimbursed under Medicare and private payors tend to follow CMS to a substantial degree.

Coverage and reimbursement by a third-party payor may depend upon a number of factors, including the third-party payor’s determination that use of a product is (i) a covered benefit under its health plan; (ii) safe, effective and medically necessary; (iii) appropriate for the specific patient; (iv) cost-effective; and (v) neither experimental nor investigational.

In the U.S. no uniform policy of coverage and reimbursement for drugs or biological products exists, and one payor’s determination to provide coverage and adequate reimbursement for a product does not assure that other payors will make a similar determination. Accordingly, decisions regarding the extent of coverage and amount of reimbursement to be provided for any of our products candidates, if approved, will be made on a payor by payor basis. The level of coverage and reimbursement for products can differ significantly from payor to payor. One payor’s decision to cover a particular medical product or service does not ensure that other payors will also provide coverage for the medical product or service, or will provide coverage at an adequate reimbursement rate. The coverage determination process may be a time consuming and costly process that will require us to provide scientific and clinical support for the use of our products to each payor separately, with no assurance that coverage and adequate reimbursement will be obtained. In order to secure coverage and reimbursement for any product that might be approved for sale, a company may need to conduct expensive pharmacoeconomic studies in order to demonstrate the medical necessity and cost-effectiveness of the product, in addition to the costs required to obtain FDA or other comparable regulatory approvals. Additionally, companies may also need to provide discounts to purchasers, private health plans or government healthcare programs.

A third-party payor’s decision to provide coverage for a product does not imply that an adequate reimbursement rate will be approved. The containment of healthcare costs has become a priority of federal, state and foreign governments and payors, and the prices of products have been a focus in this effort. Governments have shown significant interest in implementing cost-containment programs, including price controls, restrictions on 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 a company’s revenue generated from the sale of any approved products.

Coverage policies and third-party payor reimbursement rates may change at any time. Even if favorable coverage and reimbursement status is attained for one or more products for which a company or its collaborators receive regulatory approval, less favorable coverage policies and reimbursement rates may be implemented in the future, which could affect physician usage and patient demand.

Additional federal programs apply to pharmaceutical companies that affect coverage and reimbursement for drug products. For example, the Medicaid Drug Rebate Program requires pharmaceutical manufacturers to enter into and have in effect a national rebate agreement with the Secretary of the HHS as a condition for states to receive federal matching funds for the manufacturer’s outpatient drugs furnished to Medicaid patients. The ACA also expanded the universe of Medicaid utilization subject to drug rebates by requiring pharmaceutical manufacturers to pay rebates on Medicaid managed care utilization and by enlarging the population potentially eligible for Medicaid drug benefits. Pricing and rebate programs must also comply with the Medicaid rebate requirements of the U.S. Omnibus Budget Reconciliation Act of 1990.

The Medicare Prescription Drug, Improvement, and Modernization Act of 2003 (the “MMA”) established the Medicare Part D program to provide a voluntary prescription drug benefit to Medicare beneficiaries. Under Part D, Medicare beneficiaries may enroll in prescription drug plans offered by private entities that prescription drug coverage. Part D prescription drug plan sponsors are not required to pay for all covered Part D drugs, and each drug plan can develop its own drug formulary that identifies which drugs it will cover and at what tier or level. Although Part D prescription drug formularies must include drugs within each therapeutic category and class of covered Part D drugs, not necessarily all the drugs in each category or class must be included. Any formulary used by a Part D prescription drug plan must be developed and reviewed by a pharmacy and therapeutic committee. Government payment for some of the costs of prescription drugs may increase demand for products for which we receive marketing approval. However, any negotiated prices for our products covered by a Part D prescription drug plan likely will be lower than the prices we might otherwise obtain. Moreover, while the MMA applies only to drug benefits for Medicare beneficiaries, private payors

often follow Medicare coverage policy and payment limitations in setting their own payment rates. Any reduction in payment that results from the MMA may result in a similar reduction in payments from non-governmental payors.

For a drug product to receive federal reimbursement under the Medicaid or Medicare Part B programs or to be sold directly to U.S. government agencies, the manufacturer must extend discounts to entities eligible to participate in the 340B drug pricing program. The required 340B discount on a given product is calculated based on the AMP and Medicaid rebate amounts reported by the manufacturer. As of 2010, the ACA expanded the types of entities eligible to receive discounted 340B pricing, although, under the current state of the law, with the exception of children’s hospitals, these newly eligible entities will not be eligible to receive discounted 340B pricing on orphan drugs. In addition, as 340B drug pricing is determined based on AMP and Medicaid rebate data, the revisions to the Medicaid rebate formula and AMP definition described above could cause the required 340B discount to increase.

These laws, and future state and federal healthcare reform measures may be adopted in the future, any of which may result in additional reductions in Medicare and other healthcare funding and otherwise affect the prices we may obtain for any of our product candidates for which we may obtain regulatory approval or the frequency with which any such product candidate is prescribed or used.

In addition, in most foreign countries, the proposed pricing for a drug must be approved before it may be lawfully marketed. The requirements governing drug pricing and reimbursement vary widely from country to country. For example, the EU provides options for its member states to restrict the range of medicinal products for which their national health insurance systems provide reimbursement and to control the prices of medicinal products for human use. Reference pricing used by various EU Member States and parallel distribution, or arbitrage between low priced and high priced member states, can further reduce prices. A member state may approve a specific price for the medicinal product or it may instead adopt a system of direct or indirect controls on the profitability of the company placing the medicinal product on the market. In some countries, we may be required to conduct a clinical study or other studies that compare the cost effectiveness of any of our product candidates to other available therapies in order to obtain or maintain reimbursement or pricing approval. Historically, products launched in the EU do not follow price structures of the U.S. and generally prices tend to be significantly lower. Publication of discounts by third-party payors or authorities may lead to further pressure on the prices or reimbursement levels within the country of publication and other countries.

Our employees are relentlessly focused on the discovery and development of innovative medicines in which signaling by protein growth factors plays a fundamental role. We believe that passion for science is what guides us to excellence. Our commitment to changing the lives of people with serious disease is what motivates us to show up each and every day. Our people are our most important asset who help us achieve extraordinary results and create new possibilities for patients. They embody our values and bring them to life in everything we do. We are inspired and guided by these values of focusing on the patient, cultivating curiosity, collaborating with purpose, upholding high standards and accelerating breakthroughs in making a difference in the lives of patients, families and communities.

a. Employees

As of February 21, 2025, we had 196 full-time employees, of which 128 employees are engaged in research and development activities and 68 are engaged in general and administrative activities. All of our employees are based in the U.S. and a majority are based in Massachusetts. During 2024, we continued to make targeted hires to enhance our capabilities. The new employees were hired to support a variety of functions and key initiatives, including strengthening our clinical development and starting to build our commercial function, with hires in various areas of clinical development, operations and commercial leadership. We anticipate continuing to add depth and new capabilities in key areas of our business in 2025, as well as hiring to support our infrastructure and overall anticipated growth. None of our employees is represented by a labor union or covered by a collective bargaining agreement, and we believe our relationship with our employees is good.

b. Career Development and Growth

We emphasize employee development and training. To empower employees to unleash their potential individually and as a team, we invest in our employees by providing development opportunities, and the necessary resources to support their success, including mentorship guidelines, professional coaching, management and leadership training, online learning subscriptions and access to industry events and conferences. The diversity of our employees and their skillsets also offers a unique opportunity for us to learn from each other’s experiences.

c. Compensation and Benefits

Our competitive compensation programs are designed to align the compensation of our employees with our performance and to provide the proper incentives to attract, retain and motivate employees to achieve superior results. The structure of our compensation programs balances earnings for both short-term and long-term performance. We provide employee salaries that are competitive within our industry based on position, skill level, experience and knowledge. Additionally, we offer both new hire equity and annual equity grants to our employees to align the interests of our employees with the company’s mission.

We are committed to providing comprehensive benefit options and it is our intention to offer benefits that will allow our employees and their families to live healthier and more secure lives. Some examples of the benefits we offer are: medical insurance including prescription drug benefits, dental insurance, vision insurance, accident insurance, life insurance, disability insurance, health savings accounts, flexible spending accounts, wellness programs, access to mental health support and benefits, identity theft insurance and pet insurance.

In addition to ensuring our compensation programs are equitable, we also strive to provide employees with valuable recognition for their contributions to our success. We have a multi-tier reward & recognition program that aligns with our company values at all levels. Our rewards & recognition program begins with peer-to-peer recognition via an internal community board, followed by quarterly awards for outstanding achievements, and ends with an annual award for each one of our values.

d. Employee Engagement

We routinely conduct confidential employee engagement surveys to obtain feedback on a variety of topics, including culture, values, diversity, equity and inclusion, career development, employee satisfaction and tenure, and execution of our company strategy. These survey results are reviewed by our people managers so that we can continue to increase employee satisfaction and improve the well-being of our employees. We value and encourage fostering mechanisms and opportunities for two-way dialogue. We actively strive to operationalize feedback provided by employees in ways that align with our business and culture. We are also committed to communication and transparency, using multiple forums and channels to allow for the sharing of appropriate, timely information to all employees.

e. Health & Safety

Ensuring the safety and wellbeing of our employees and communities is of the utmost importance to us, particularly following the COVID-19 pandemic. What we have seen as a result of the pandemic is that flexibility is top of mind and a key consideration. We continue to offer access to COVID tests and masks at no cost to our employees and visitors.

The need to provide the flexibility to work from home has refocused our work model. We’ve helped employees set up home offices, provided them access to tools to perform their jobs remotely, provided ergonomic assessments of their working environments, and helped them address IT connectivity. We’ve also found ways to continue to foster collaboration and community through events like virtual trivia nights, scavenger hunts, coffee chats, charitable giving and lunch-n-learns, that we would normally do in person.

f. Diversity, Equity & Inclusion (“DE&I”)

We believe that fostering diversity, equity and inclusion is a business imperative which supports and encourages individuals to show up as their whole selves. Investing in meaningful DE&I work enhances culture and employee experience. We are committed to creating and maintaining a diverse, equitable, inclusive, and safe work environment. As we grow and mature, we will continue to infuse DE&I within the business including: identifying barriers that impact recruitment, development, and retention of underrepresented employees, identifying educational content, communicating the value and impact of DE&I on goals and objectives, all while continuing to focus on hiring diverse talent at all levels of the company. Our ability to innovate and meet people’s needs is strongest when all voices are heard and valued.

Our corporate headquarters and operations are located in Cambridge, Massachusetts.

In November 2019, we entered into a lease of laboratory and office space at 301 Binney Street in Cambridge, Massachusetts and in 2021 we relocated our corporate headquarters to this location. The expiration date was originally in August 2025 and included an option to extend the term by two years. In May 2024, we entered into the First Amendment to the Lease to extend the term for approximately two years, commencing on August 19, 2025 with an option to extend the term by five years.

We believe that our facility at 301 Binney Street is adequate to meet our current needs, and that suitable additional space will be available as and when needed.

XVL. Legal Proceedings

From time to time, we may be involved in various claims and legal proceedings relating to claims arising out of our operations. We are not currently a party to any material legal proceedings.

XVIL. Website Access to Reports

We are subject to the informational requirements of the Exchange Act and are required to file annual, quarterly and current reports, proxy statements and other information with the SEC. You can read our SEC filings, including the registration statement, at the SEC’s website at www.sec.gov. We also maintain a website at http://www.scholarrock.com. You may access, free of charge, our annual reports on Form 10-K, quarterly reports on Form 10-Q, current reports on Form 8-K and any amendments to those reports, as soon as reasonably practicable after such material is electronically filed with, or furnished to, the SEC. The information that is posted on or is accessible through our website is not incorporated by reference into this Annual Report on Form 10-K and should not be considered part of this or any other report that we file with or furnish to the SEC.