Regeneron trial preserves lean mass
- Regeneron said June 2, 2025, that interim Phase 2 COURAGE data showed semaglutide plus trevogrumab, with or without garetosmab, preserved lean mass in obesity treatment. - In the interim cohort, semaglutide alone lost 7.9 pounds of lean mass, while combination arms spared roughly 50.8% to 80.9% of that loss. - The readout targets a key concern around GLP-1 weight loss: how much comes from muscle, not fat. (regeneron.com)
Weight-loss drugs can cut fat, but they can also cut muscle. Regeneron said interim data from its Phase 2 COURAGE trial suggest it may be possible to keep more lean mass while patients lose weight on semaglutide. (regeneron.com) (patientcareonline.com) Semaglutide is the active ingredient in Wegovy and works by lowering appetite and slowing stomach emptying. In COURAGE, Regeneron paired it with trevogrumab, an antibody that blocks myostatin, a protein that helps limit muscle growth. (patientcareonline.com) (clinicaltrials.gov) The company also tested a three-drug arm that added garetosmab, an antibody against activin A, another signaling protein tied to muscle regulation. The trial on ClinicalTrials.gov is listed as NCT06299098 and was designed to compare body weight, fat mass, and lean mass against semaglutide alone. (clinicaltrials.gov) (regeneron.com) Regeneron’s interim analysis was run when 50% of participants had reached week 26. In the semaglutide-only group, 34.5% of weight loss came from lean mass, equal to 7.9 pounds, according to the company. (patientcareonline.com) (regeneron.com) The combination groups lost more fat and held on to more lean tissue than semaglutide alone. Regeneron said semaglutide plus lower-dose trevogrumab preserved 50.8% of lean mass that otherwise would have been lost, the higher-dose pair preserved 51.3%, and the triplet preserved 80.9%. (patientcareonline.com) (regeneron.com) That question has become central as GLP-1 drugs move from diabetes care into broad obesity treatment. Doctors and patients have been weighing not just how many pounds come off, but what those pounds are made of. (patientcareonline.com) (regeneron.com) Regeneron later reported complete 26-week results on September 17, 2025, and said they were consistent with the interim readout. In that update, the company said 33% of semaglutide-induced weight loss was due to lean mass loss and that adding trevogrumab prevented about half of that loss. (regeneron.com) The company also said the full 26-week data showed numeric improvements in waist circumference, blood pressure, cholesterol, triglycerides, and A1C across treatment groups. Julio Rosenstock, the trial’s lead principal investigator, said the results showed “a meaningful opportunity” to preserve muscle mass while enhancing fat loss. (regeneron.com) COURAGE was built in two 26-week periods: a weight-loss phase followed by a weight-maintenance phase. The next question is whether preserving lean mass during the first six months also holds up after the scale stops moving as quickly. (clinicaltrials.gov) (regeneron.com)
