The FDA approved Regeneron’s activin A-targeting antibody garetosmab, branded Pasatru, for adults with fibrodysplasia ossificans progressiva (FOP). The decision gives patients a second FDA-approved therapy for the ultra-rare disorder, following Ipsen’s Sohonos (palovarotene). Regeneron’s approval follows a pivotal Phase 3 program and positions Pasatru as an option for patients impacted by the progressive formation of bone in soft tissues, which can severely limit mobility early in life. The company’s commercialization plans will be closely watched because FOP is small but highly underserved, and payer coverage decisions can materially affect uptake. Industry attention is likely to focus on how Pasatru performs in real-world settings relative to existing FOP therapy, including safety management and practical dosing considerations. Regulators expect postmarket data as with other biologics in rare disease. With the approval, Regeneron also gains momentum for its broader pipeline in muscle and connective-tissue biology where neutralizing activin A-related signaling has emerged as a viable approach.