1. Nature of the Business
Scholar Rock Holding Corporation (the “Company”) is 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, 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. By targeting the signaling proteins at the cellular level and acting in the disease microenvironment, the Company believes that it may avoid the historical dose-limiting safety challenges associated with inhibiting growth factors for therapeutic effect.
The Company’s 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 spinal muscular atrophy (“SMA”). The Company is conducting 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. In 2023, the Company completed enrollment for the Phase 3 SAPPHIRE trial. In 2024, the Company announced data from the Phase 2 TOPAZ trial extension period which showed patient outcomes at 48 months of treatment with apitegromab. 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 European Medicines Agency (“EMA”) granted Priority Medicine (“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, the Company announced plans to expand into cardiometabolic disorders and advance its anti-myostatin program with SRK-439, a novel, fully human anti-myostatin monoclonal antibody, for evaluation in cardiometabolic disorders, including obesity, towards a potential investigational new drug (“IND”) submission in 2025. To inform the development of SRK-439, in May 2024 the Company 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 receptor agonist (“GLP-1 RA”), with data expected in the second quarter of 2025.
The Company’s second product candidate, SRK-181, a highly selective inhibitor of the activation of latent TGFβ is being developed for the treatment of cancers that are resistant to checkpoint inhibitor 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 the Company’s 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. The Phase 1 DRAGON trial completed enrollment in December 2023 and continues to treat patients who remain on study. This two-part clinical trial consists of a dose escalation portion (Part A) and a dose expansion evaluating SRK-181 in combination with an approved anti-PD- (L)1 antibody therapy (Part B). Part B includes the following active cohorts: urothelial carcinoma, cutaneous melanoma, non-small cell lung cancer, clear cell renal cell carcinoma, and head and neck squamous cell carcinoma. Safety, efficacy and biomarker data were presented in November 2023 at the Society for Immunotherapy of Cancer 38th Annual Meeting and in June 2024 at the American Society of Clinical Oncology (“ASCO”) annual meeting.
Additionally, the Company continues to create a pipeline of product candidates 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. 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