Regeneron Pharmaceuticals Inc. (NASDAQ:REGN) reported positive results from its Phase 3 OPTIMA trial of garetosmab in adults with fibrodysplasia ossificans progressiva (FOP), meeting the study's primary endpoint.
FOP is a rare genetic disorder in which muscle, tendon, and ligament tissue progressively turn into bone, creating a "second skeleton" that limits mobility.
At 56 weeks, garetosmab at 3 mg/kg and 10 mg/kg reduced new bone lesions by 94% and 90%, respectively, compared with placebo.
Garetosmab is a monoclonal antibody that neutralizes Activin A, a key driver of HO lesions in FOP.
At 56 weeks, no patients discontinued garetosmab, while one placebo patient withdrew due to an ovarian cyst. Skin and soft tissue infections increased with dose (7, 9, and 15 cases for placebo, 3 mg/kg, and 10 mg/kg, respectively), but there was no dose-dependent rise in nosebleeds or serious bleeding events. Musculoskeletal pain decreased in both garetosmab arms (14, 6, and 4 cases for placebo, 3 mg/kg, and 10 mg/kg). No deaths occurred.
U.S. regulatory submission is planned for year-end 2025, with global submissions in 2026. A Phase 3 trial in adolescents and children (OPTIMA 2) is expected to start next year.
Price Action: REGN stock is up 1.78% at $585.28 at the last check on Wednesday.
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