Scholar Rock Announces Initiation of Phase 2 EMBRAZE Trial of Apitegromab in Obesity and New Preclinical Data Supporting SRK-439 in Obesity

Scholar Rock (NASDAQ: SRRK), a late-stage biopharmaceutical company focused on advancing innovative treatments for spinal muscular atrophy (SMA), cardiometabolic disorders, and other serious diseases where protein growth factors play a fundamental role, today announced the initiation of the Phase 2 EMBRAZE proof-of-concept trial, designed to assess the safety and efficacy of apitegromab, a highly selective myostatin inhibitor, to preserve lean muscle mass in individuals living with obesity and on background therapy of a GLP-1 receptor agonist (GLP-1 RA). The results from this trial will inform the development of SRK-439, a novel investigational selective myostatin inhibitor optimized for the treatment of cardiometabolic disorders, including obesity.

The Company also announced new preclinical data from a head-to-head comparison of SRK-439 and an anti-activin receptor II (anti-ActRII) antibody, which demonstrate SRK-439’s potential as best in class in preserving lean mass in patients on GLP-1 RAs. This data will be presented by Mo Qatanani, Ph.D., Chief Scientific Officer, at Scholar Rock’s Investor Event, which begins today at 8:30 a.m. ET and is being held in New York City.

“We are thrilled to have initiated the EMBRAZE clinical trial ahead of schedule and to share new data from our SRK-439 program, which we believe further support our hypothesis that selective latent myostatin inhibition has advantages over less selective approaches to safely and effectively maintain lean muscle mass,” said Jay Backstrom, M.D., MPH, President and Chief Executive Officer at Scholar Rock. “Selectivity is key in mitigating potential safety concerns for this patient population and we look forward to sharing additional preclinical data at the American Diabetes Association 84^th Scientific Sessions in June to support the best-in-class potential of SRK-439.”

New SRK-439 Data

For the head-to-head preclinical research study, the Company generated and tested an anti-ActRII antibody (a murine equivalent of bimagrumab), along with a murine equivalent of SRK-439 in a weight-stable diet induced obesity (DIO) mouse model. Mice were given either semaglutide (0.04mg/kg, daily) with an IgG control antibody (weekly, 20mg/kg) or semaglutide (0.04mg/kg, daily) in combination with weekly injections of either SRK-439 (0.3-10mg/kg) or of the anti-ActRII antibody (0.3-20mg/kg). Quantitative nuclear magnetic resonance (qNMR) was used to analyze change in lean mass after four weeks of treatment.