10:35 AM EDT, 09/17/2025 (MT Newswires) -- Regeneron Pharmaceuticals ( REGN ) said Wednesday updated Phase 2 trial results suggest that combining its experimental antibodies -- trevogrumab or garetosmab -- with semaglutide may help treat obesity more effectively by limiting muscle loss during weight reduction.

The 26-week analysis confirmed earlier findings that about one-third of weight loss from semaglutide, a GLP-1 receptor agonist marketed by Novo Nordisk ( NVO ) as Ozempic and Wegovy, stems from loss of lean mass, Regeneron said. Adding trevogrumab, an anti-myostatin antibody, cut that muscle loss by half, and patients also showed improvements in waist circumference, blood pressure, cholesterol, triglycerides, and A1C levels across all treatment groups, the company said.

While the drug combinations were generally well-tolerated, common side effects included nausea, fatigue, and diarrhea, the company said. A separate regimen combining semaglutide with both trevogrumab and garetosmab showed a higher dropout rate due to adverse effects.

Trevogrumab and garetosmab remain investigational and have not yet been evaluated by any regulatory agency for safety or efficacy, the company said.

Regeneron shares rose 1.6% in recent Wednesday trading, and Novo Nordisk ( NVO ) gained 2.9%.

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