Regeneron says trevogrumab cuts muscle loss by 70%

Regeneron Pharmaceuticals announced new results on October 1, 2026, from its Phase 2 COURAGE trial evaluating trevogrumab, an anti-myostatin therapy. The study investigated the drug's ability to prevent lean mass and muscle loss during weight reduction induced by GLP-1 receptor agonists in people living with obesity.

In a predefined MRI substudy, lower-dose trevogrumab preserved almost 70% of the thigh muscle that would have otherwise been lost with semaglutide treatment alone. Findings from the trial were presented at the European Association for the Study of Diabetes Annual Meeting and are in press with The Lancet.

The 52-week trial evaluated participants with a body mass index of at least 30 kg/m2 across two portions. A higher-dose portion tested 200 mg or 400 mg of trevogrumab with 2.4 mg of semaglutide for 26 weeks, followed by 26 weeks without semaglutide. A lower-dose portion evaluated 25 mg or 75 mg alongside 2.4 mg of semaglutide for 52 weeks, demonstrating lean mass preservation at both 26 and 52 weeks compared to placebo.

Lower doses were generally well tolerated, with adverse events reported in 77% of participants on trevogrumab compared to 82% on placebo. The most common adverse events affecting at least 10% of patients were nausea, constipation, diarrhea, and vomiting. Regeneron now plans to start a Phase 2 trial combining trevogrumab with GLP-1 receptor agonists in older adults with obesity and decreased muscle mass or strength.