Scholar Rock announced that the U.S. Food and Drug Administration (FDA) has cleared the company's Investigational New Drug (IND) application for its Phase 2 proof-of-concept trial of apitegromab to treat obesity in patients taking a GLP-1 receptor agonist (GLP-1 RA). The Phase 2 trial is a randomized, double-blind, placebo-controlled, multi-center study to evaluate the effect of apitegromab, a highly selective myostatin inhibitor, to safely preserve lean muscle mass as an adjunctive therapy in overweight and obese adults who are taking a GLP-1 RA. Trial initiation is on track for mid-2024, and data from the apitegromab Phase 2 trial are expected in mid-2025.

In parallel, Scholar Rock is developing SRK-439, a novel investigational selective myostatin inhibitor, optimized for the treatment of obesity. The Company plans to file an IND for SRK-439 in 2025. SRK-439 is a novel, preclinical, investigational myostatin inhibitor that has high in vitro affinity for pro- and latent myostatin and maintains myostatin specificity (i.e., no GDF11 or Activin-A binding), and is initially being developed for the treatment of obesity.

Based on preclinical data, SRK-439 has the potential to support healthier weight management by preserving lean mass and enhancing fat mass loss. The efficacy and safety of SRK-439 have not been established and SRK-439 has not been approved for any use by the FDA or any other regulatory agency. Apitegromab is an investigational fully human monoclonal antibody inhibiting myostatin activation by selectively binding the pro- and latent forms of myostatin in the skeletal muscle.

It is the first muscle-targeted treatment candidate to demonstrate clinical proof of concept in spinal muscular atrophy (SMA). Myostatin, a member of the TGFß superfamily of growth factors, is expressed primarily by skeletal muscle cells, and the absence of its gene is associated with an increase in muscle mass and strength in multiple animal species, including humans. Scholar Rock believes that its highly selective targeting of pro- and latent forms of myostatin with apitegromab may lead to a clinically meaningful improvement in motor function in patients with SMA.

The U.S. Food and Drug Administration (FDA) has granted Fast Track, Orphan Drug and Rare Pediatric Disease designations, and the European Medicines Agency (EMA) has granted Priority Medicines (PRIME) and Orphan Medicinal Product designations, to apitegromab for the treatment of SMA. The efficacy and safety of apitegromab have not been established and apitegromab has not been approved for any use by the FDA or any other regulatory agency.