Press release
Regeneron Announces Positive Phase 3 Trial in Adults with Ultra-Rare Genetic Disorder Fibrodysplasia Ossificans Progressiva (FOP), Demonstrating that Garetosmab Prevents Greater than 99% of Abnormal Bone Formation
FOP is a disease in which muscles, tendons and ligaments are progressively replaced by bone, leading to eventual incapacitation Garetosmab is the first and
About this update from Regeneron Pharmaceuticals, Inc.
[{"type":"text","content":"FOP is a disease in which muscles, tendons and ligaments are progressively replaced by bone, leading to eventual incapacitation Garetosmab is the first and only treatment to demonstrate a dramatic reduction in both number and volume of abnormal bone lesions (heterotopic ossification, or HO lesions) in adults with FOP Primary endpoint was met, showing a 90% or greater reduction in new HO lesions at 56 weeks, and garetosmab also led to a greater than 99% reduction in the total volume of new HO lesions Based on these data and the safety profile, the Independent Data Monitoring Committee (IDMC) recommended those receiving placebo be transitioned to garetosmab as soon as possible; U.S. regulatory submission of garetosmab in adults planned for year-end 2025 TARRYTOWN, N.Y., Sept. 17, 2025 (GLOBE NEWSWIRE) -- Regeneron Pharmaceuticals, Inc. (NASDAQ: REGN) today announced the primary endpoint was met in the Phase 3 OPTIMA trial investigating garetosmab in adults with fibrodysplasia ossificans progressiva (FOP). At 56 weeks, both doses of garetosmab, 3 mg/kg and 10 mg/kg, were highly efficacious in reducing the number of new bone lesions (heterotopic ossification, or HO lesions) as compared to placebo, demonstrating a 94% and 90% reduction, respectively. Garetosmab is a monoclonal antibody that neutralizes the Activin A protein, which Regeneron scientists discovered to be a critical protein in the development of HO lesions in people with FOP. “Heterotopic ossification is a hallmark of FOP, a horrific disease in which muscles, tendons and ligaments are progressively replaced by bone, gradually incapacitating patients,” said Professor Richard Keen, Director of the Metabolic Bone Disease Centre, Royal National Orthopaedic Hospital, London, and global primary investigator of the OPTIMA trial. “The OPTIMA trial results clearly illustrate the potential of garetosmab to alter the disease and reduce new lesions that define this condition. Notably, garetosmab is the first and only investigational therapy to demonstrate a dramatic reduction in both the number and volume of abnormal bone lesions.\" OPTIMA, a global, multi-center, randomized, double-blind, placebo-controlled trial, enrolled 63 people with FOP aged 18 years and older. Trial participants were randomized to intravenously receive either placebo, 3 mg/kg garetosmab, or 10 mg/kg garetosma...