Regeneron Plans Trial in Older Adults After Muscle-Sparing Antibody Preserves Lean Mass

On October 1, 2026, the company reported 52-week results from its Phase 2 COURAGE trial. The trial tested trevogrumab, an antibody that blocks myostatin, alongside semaglutide 2.4 mg in people with obesity. According to Regeneron, the data were presented at the European Association for the Study of Diabetes meeting and are in press with The Lancet.

The numbers come from the lower-dose portion of the trial, with lean mass measured by DXA scan. Over 52 weeks, people on semaglutide plus placebo lost 7.3% of their lean mass. Those who also took 25 mg of trevogrumab lost 5.8%. Those who took 75 mg lost 4.2%, which Regeneron describes as 42.5% preservation relative to placebo. In an MRI substudy of participants with evaluable data, the lower doses preserved about 69% to 72% of the thigh muscle that semaglutide alone would have cost at 52 weeks.

The drug did not add to the weight loss itself. Regeneron says lower-dose trevogrumab did not meaningfully enhance the weight loss achieved with semaglutide alone. Adverse events were reported by 77% of lower-dose trevogrumab participants and 82% of those on placebo. The most common were nausea, constipation, diarrhea and vomiting.

The strategic signal is in the next step. Regeneron plans a Phase 2 trial of trevogrumab with GLP-1-based therapies in older adults with obesity and decreased muscle mass and/or strength. A prespecified subgroup analysis supports that choice. Participants with low lean mass at the start, defined using the imaging part of the sarcopenia definition from the Foundation for the National Institutes of Health, lost more lean mass on semaglutide alone. They also showed numerically more preservation with trevogrumab.

Regeneronʼs Boaz Hirshberg said the approach addresses “not the quantity, but rather the quality, of weight loss.” The company frames adiposity as the main driver of obesity-related disease, and says its aim is to raise the share of weight lost that is fat.

What this could mean for the market is analysis, not something the release states. A product aimed at older or sarcopenic patients would compete on a different measure than weight-loss totals. It might support a separate patient group, separate pricing arguments and a separate regulatory case. The release says nothing about pricing, trial endpoints or how regulators would view such a claim. It also reports lean mass and muscle volume, not strength or physical function, and it gives no numbers for the higher-dose arm. This is the weakest part of the argument: preserved lean mass has not been shown here to mean better function.

Important limits apply. The results are company-issued. Regeneron states that the safety and efficacy of trevogrumab and olatorepatide have not been evaluated by any regulatory authority. The company also holds rights outside the Chinese Mainland, Hong Kong and Macau to olatorepatide, a GLP-1/GIP receptor agonist that its partner Hansoh has tested in a Phase 3 trial in Chinese patients. Any pairing with trevogrumab would be speculation; the release does not suggest one.

Watch for the design of the older-adult trial, especially whether it measures strength and function alongside lean mass, and for the full Lancet publication.

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