Nature of the Business and Basis of Presentation	12 Months Ended
Dec. 31, 2025
Nature of the Business and Basis of Presentation
Nature of the Business and Basis of Presentation	1. Nature of the Business and Basis of Presentation Organization Scholar Rock Holding Corporation and its subsidiaries (collectively, the “Company”) is a global biopharmaceutical company dedicated to dramatically improving the lives of children and adults with spinal muscular atrophy (“SMA”) and additional rare, severe and debilitating neuromuscular diseases. As a leader in the biology of the transforming growth factor beta (“TGFβ”) superfamily, the Company’s novel understanding of the molecular mechanisms of growth factor activation enabled the development of a proprietary platform for the discovery and development of monoclonal antibodies that locally and selectively target the precursor, or latent, forms of growth factors. Based on the Company’s innovative, proprietary, and scalable technology platform, the Company is building a world-leading anti-myostatin pipeline. The Company’s lead pipeline product candidates include apitegromab, a subcutaneous formulation of apitegromab, and SRK-439. Apitegromab is a novel, investigational, fully human monoclonal antibody that inhibits myostatin activation by selectively binding the pro- and latent forms of myostatin in skeletal muscle. Myostatin is a catabolic agent that functions as a negative regulator of muscle mass, therefore inhibition of myostatin results in increased muscle mass and strength. Apitegromab is in development for the treatment of people with SMA and for the treatment of people with facioscapulohumeral muscular dystrophy (“FSHD”). Positive data from the successful Phase 3 SAPPHIRE study evaluating apitegromab in children and adults with SMA was reported in October 2024. The Company submitted a U.S. Biologics License Application (“BLA”) to the U.S. Food and Drug Administration (“FDA”) in January 2025 and the BLA was granted priority review designation. In September 2025, the Company received a Complete Response Letter (“CRL”) from the FDA related to observations identified during an FDA inspection of a third-party fill-finish facility. The facility was issued a Form 483 by the FDA in July 2025 and the inspection classification of this facility is official action indicated (“OAI”). The observations were related to the facility and were not specific to apitegromab. The CRL did not cite any other approvability concerns, including apitegromab’s efficacy and safety data or the third-party drug substance manufacturer. In November 2025, the Company completed an in-person Type A meeting with the FDA that included participation of representatives from the third-party fill-finish facility. Also in November 2025, the third-party fill-finish facility received a Warning Letter from the FDA and continues to work with the FDA to resolve the outstanding issues cited in the warning letter. The Company plans to resubmit the apitegromab BLA at such time after the facility resolves the cGMP deficiencies identified in the CRL. In March 2025, the Company submitted to the European Medicines Agency (“EMA”) and received validation of its marketing authorisation application (“MAA”) for apitegromab for the treatment of SMA. If apitegromab is approved by the FDA or EMA, the Company expects to initiate a commercial product launch in the applicable jurisdictions upon approval. The Company continues to develop apitegromab in SMA with its ongoing long-term extension ONYX trial and its Phase 2 OPAL trial in SMA patients under two years of age, which was initiated in the third quarter of 2025. Additionally, a Phase 2 study evaluating apitegromab in patients with FSHD is expected to initiate in mid-2026. In addition to the current intravenous (“IV”) formulation, the Company is developing a subcutaneous (“SC”) formulation of apitegromab. A Phase 1 study in healthy volunteers has been completed, demonstrating that SC apitegromab has favorable bioavailability and a comparable pharmacodynamic profile relative to IV administered apitegromab. Further development activities are ongoing, including planned FDA and EMA regulatory engagements. The Company’s clinical-stage pipeline also includes SRK-439, a novel, investigational, subcutaneously administered fully human anti-pro/latent myostatin antibody that has high inhibitory potency while maintaining selectivity towards myostatin. SRK-439 is being developed for the treatment of patients with rare, severe, and debilitating neuromuscular diseases. A Phase 1 study of SRK-439 in healthy volunteers is currently underway, with topline data anticipated in the second half of 2026. As the Company focuses its strategy on rare neuromuscular diseases, the Company is currently seeking partnerships for its additional programs. These programs include: SRK-181, a Phase 2-ready investigational inhibitor of latent TGFβ1 in development for the treatment of patients with solid tumors that are resistant to anti-PD-(L)1 antibody therapies; SRK-373, an investigational, highly selective inhibitor of the latent TGFβ1 isoform with selective activity in the fibrotic extracellular matrix, in preclinical development for the treatment of fibrotic diseases; and SRK-256, an investigational inhibitor of RGMc, or hemojuvelin, in preclinical development for the treatment of iron-restricted anemias. We are also seeking partners to further evaluate the potential for myostatin inhibition in combination with GLP-1 weight loss approaches following our positive Phase 2 EMBRAZE study, demonstrating proof-of-concept in the ability of apitegromab to drive statistically significant preservation of lean mass during tirzepatide-induced weight loss. Beyond the clinical-stage product candidates, the company’s early-stage pipeline includes additional programs for the treatment of patients with rare, severe, and debilitating neuromuscular diseases. The Company was originally formed in May 2012. Its principal offices are in Cambridge, Massachusetts. Since its inception, the Company’s operations have focused on research and development of monoclonal antibodies that selectively inhibit activation of growth factors for therapeutic effect, as well as establishing the Company’s intellectual property portfolio and performing research and development activities. The Company has primarily financed its operations through various equity financings, the exercise of stock options and warrants, as well as research and development collaboration agreements and the Company’s debt facility (Note 14). Revenue generation activities have been limited to two collaborations, both containing research services and the issuance of a license. No revenues have been recorded from the sale of any commercial product. The Company is subject to a number of risks similar to other life science companies, including, but not limited to, successful discovery and development of its drug candidates, raising additional capital, development by its competitors of new technological innovations, protection of proprietary technology and regulatory approval and market acceptance of the Company’s product candidates. The Company anticipates that it will continue to incur significant operating losses for the next several years as it continues to develop and seek regulatory approval for its product candidates. The Company believes that its existing cash, cash equivalents and marketable securities as of December 31, 2025, along with cash available to the Company (see Note 18), will be sufficient to allow the Company to fund its current operations through at least a period of one year after the date these financial statements are issued. Basis of Presentation The consolidated financial statements include the accounts of Scholar Rock Holding Corporation and its wholly owned subsidiaries. All intercompany balances have been eliminated in consolidation. These consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the U.S. (“GAAP”). Any reference in these notes to applicable guidance is meant to refer to the authoritative GAAP as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Update (“ASU”) of the Financial Accounting Standards Board (“FASB”).

Nature of the Business and Basis of Presentation

12 Months Ended

Dec. 31, 2025

Nature of the Business and Basis of Presentation

Nature of the Business and Basis of Presentation

1. Nature of the Business and Basis of Presentation

Organization

Scholar Rock Holding Corporation and its subsidiaries (collectively, the “Company”) is a global biopharmaceutical company dedicated to dramatically improving the lives of children and adults with spinal muscular atrophy (“SMA”) and additional rare, severe and debilitating neuromuscular diseases. As a leader in the biology of the transforming growth factor beta (“TGFβ”) superfamily, the Company’s novel understanding of the molecular mechanisms of growth factor activation enabled the development of a proprietary platform for the discovery and development of monoclonal antibodies that locally and selectively target the precursor, or latent, forms of growth factors. Based on the Company’s innovative, proprietary, and scalable technology platform, the Company is building a world-leading anti-myostatin pipeline.

The Company’s lead pipeline product candidates include apitegromab, a subcutaneous formulation of apitegromab, and SRK-439.

Apitegromab is a novel, investigational, fully human monoclonal antibody that inhibits myostatin activation by selectively binding the pro- and latent forms of myostatin in skeletal muscle. Myostatin is a catabolic agent that functions as a negative regulator of muscle mass, therefore inhibition of myostatin results in increased muscle mass and strength. Apitegromab is in development for the treatment of people with SMA and for the treatment of people with facioscapulohumeral muscular dystrophy (“FSHD”).

Positive data from the successful Phase 3 SAPPHIRE study evaluating apitegromab in children and adults with SMA was reported in October 2024. The Company submitted a U.S. Biologics License Application (“BLA”) to the U.S. Food and Drug Administration (“FDA”) in January 2025 and the BLA was granted priority review designation. In September 2025, the Company received a Complete Response Letter (“CRL”) from the FDA related to observations identified during an FDA inspection of a third-party fill-finish facility. The facility was issued a Form 483 by the FDA in July 2025 and the inspection classification of this facility is official action indicated (“OAI”). The observations were related to the facility and were not specific to apitegromab. The CRL did not cite any other approvability concerns, including apitegromab’s efficacy and safety data or the third-party drug substance manufacturer. In November 2025, the Company completed an in-person Type A meeting with the FDA that included participation of representatives from the third-party fill-finish facility. Also in November 2025, the third-party fill-finish facility received a Warning Letter from the FDA and continues to work with the FDA to resolve the outstanding issues cited in the warning letter. The Company plans to resubmit the apitegromab BLA at such time after the facility resolves the cGMP deficiencies identified in the CRL. In March 2025, the Company submitted to the European Medicines Agency (“EMA”) and received validation of its marketing authorisation application (“MAA”) for apitegromab for the treatment of SMA. If apitegromab is approved by the FDA or EMA, the Company expects to initiate a commercial product launch in the applicable jurisdictions upon approval.

The Company continues to develop apitegromab in SMA with its ongoing long-term extension ONYX trial and its Phase 2 OPAL trial in SMA patients under two years of age, which was initiated in the third quarter of 2025. Additionally, a Phase 2 study evaluating apitegromab in patients with FSHD is expected to initiate in mid-2026.

In addition to the current intravenous (“IV”) formulation, the Company is developing a subcutaneous (“SC”) formulation of apitegromab. A Phase 1 study in healthy volunteers has been completed, demonstrating that SC apitegromab has favorable bioavailability and a comparable pharmacodynamic profile relative to IV administered apitegromab. Further development activities are ongoing, including planned FDA and EMA regulatory engagements.

The Company’s clinical-stage pipeline also includes SRK-439, a novel, investigational, subcutaneously administered fully human anti-pro/latent myostatin antibody that has high inhibitory potency while maintaining selectivity towards myostatin. SRK-439 is being developed for the treatment of patients with rare, severe, and debilitating neuromuscular

diseases. A Phase 1 study of SRK-439 in healthy volunteers is currently underway, with topline data anticipated in the second half of 2026.

As the Company focuses its strategy on rare neuromuscular diseases, the Company is currently seeking partnerships for its additional programs. These programs include: SRK-181, a Phase 2-ready investigational inhibitor of latent TGFβ1 in development for the treatment of patients with solid tumors that are resistant to anti-PD-(L)1 antibody therapies; SRK-373, an investigational, highly selective inhibitor of the latent TGFβ1 isoform with selective activity in the fibrotic extracellular matrix, in preclinical development for the treatment of fibrotic diseases; and SRK-256, an investigational inhibitor of RGMc, or hemojuvelin, in preclinical development for the treatment of iron-restricted anemias. We are also seeking partners to further evaluate the potential for myostatin inhibition in combination with GLP-1 weight loss approaches following our positive Phase 2 EMBRAZE study, demonstrating proof-of-concept in the ability of apitegromab to drive statistically significant preservation of lean mass during tirzepatide-induced weight loss.

Beyond the clinical-stage product candidates, the company’s early-stage pipeline includes additional programs for the treatment of patients with rare, severe, and debilitating neuromuscular diseases. The Company was originally formed in May 2012. Its principal offices are in Cambridge, Massachusetts.

Since its inception, the Company’s operations have focused on research and development of monoclonal antibodies that selectively inhibit activation of growth factors for therapeutic effect, as well as establishing the Company’s intellectual property portfolio and performing research and development activities. The Company has primarily financed its operations through various equity financings, the exercise of stock options and warrants, as well as research and development collaboration agreements and the Company’s debt facility (Note 14).

Revenue generation activities have been limited to two collaborations, both containing research services and the issuance of a license. No revenues have been recorded from the sale of any commercial product.

The Company is subject to a number of risks similar to other life science companies, including, but not limited to, successful discovery and development of its drug candidates, raising additional capital, development by its competitors of new technological innovations, protection of proprietary technology and regulatory approval and market acceptance of the Company’s product candidates. The Company anticipates that it will continue to incur significant operating losses for the next several years as it continues to develop and seek regulatory approval for its product candidates.

The Company believes that its existing cash, cash equivalents and marketable securities as of December 31, 2025, along with cash available to the Company (see Note 18), will be sufficient to allow the Company to fund its current operations through at least a period of one year after the date these financial statements are issued.

Basis of Presentation

The consolidated financial statements include the accounts of Scholar Rock Holding Corporation and its wholly owned subsidiaries. All intercompany balances have been eliminated in consolidation.

These consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the U.S. (“GAAP”). Any reference in these notes to applicable guidance is meant to refer to the authoritative GAAP as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Update (“ASU”) of the Financial Accounting Standards Board (“FASB”).