Scholar Rock (NASDAQ: SRRK) has announced new preclinical data for SRK-439, a myostatin inhibitor, demonstrating significant lean mass preservation and attenuation of fat mass rebound following the withdrawal of glp-1 receptor agonist (GLP-1 RA) therapy. The company has begun dosing participants in the phase 2 Embraze proof-of-concept trial, evaluating the safety and efficacy of apitegromab, an investigational myostatin inhibitor, in preserving lean muscle mass in individuals living with obesity.
The preclinical research study involved testing SRK-439 in a diet-induced obesity (DIO) mouse model. Mice treated with SRK-439 showed a preservation of lean mass during GLP-1 RA-induced weight loss and a significant increase in lean mass after the discontinuation of GLP-1 RA therapy compared to the control group. Additionally, SRK-439 administration attenuated the fat mass rebound after GLP-1 RA withdrawal, leading to a more favorable body composition in the mice.
The results from the study showed that mice administered with SRK-439 had higher relative lean mass (65.8%) and lower relative fat mass (18.0%) at the end of the withdrawal period compared to the control group (57.1% lean mass and 28.7% fat mass). The absolute lean mass at 8 weeks was significantly higher in the SRK-439 group compared to the control group, with a p-value of less than 0.0001. Similarly, the relative lean mass at 8 weeks also showed a significant difference between the two groups, with a p-value of less than 0.001.
Dr. Mo Qatanani, Chief Scientific Officer at Scholar Rock, emphasized that the preclinical data provide compelling evidence of SRK-439's potential to contribute to healthier weight management and long-term metabolic benefits during and after GLP-1 RA treatment.
The Embraze trial, in which the first participants have been dosed, is a randomized, double-blind, placebo-controlled, phase 2 proof-of-concept trial evaluating the efficacy, safety, and pharmacokinetics of apitegromab in adults with overweight or obesity who are taking a GLP-1 RA. The primary endpoint of the trial is the change from baseline at week 24 in lean mass assessed by dual-energy X-ray absorptiometry.
As a result of these announcements, the company's shares have moved -1.2% on the market, and are now trading at a price of $8.35. For more information, read the company's full 8-K submission here.
