Efficacy and safety of garetosmab, an activin A-blocking antibody, in fibrodysplasia ossificans progressiva (OPTIMA): a randomised, double-blind, placebo-controlled, phase 3 trial.

Garetosmab significantly reduces new heterotopic bone lesions in adults with fibrodysplasia ossificans progressiva, with up to 94% fewer lesions than placebo.

• Why it matters: FOP is a rare, debilitating genetic disorder with limited treatment options, making effective therapies urgently needed to prevent progressive heterotopic ossification and improve patient outcomes.
• What they did: A phase 3, randomized, double-blind trial involving 63 adults tested garetosmab at two doses versus placebo, measuring new bone lesions and adverse events over 56 weeks.
• The result: Garetosmab markedly decreased new heterotopic bone formation, with the 3 mg/kg dose reducing lesions by 94%, and was generally well tolerated, supporting its potential as a disease-modifying therapy for FOP.