FDA approved zilurgisertib (Atebrioz) as the first ALK2 inhibitor for patients with fibrodysplasia ossificans progressiva (FOP) aged 12 and older. The approval was based on Phase 2 PROGRESS study data, with the sponsor reporting a 99.9% reduction in new heterotopic ossification lesion volume. The approval marks a regulatory turning point for a rare disease long defined by progressive, painful flare-ups and irreversible new bone formation. It also adds another ALK2 pathway option to the FOP treatment landscape, where prior medical management has focused largely on symptom control. The development history credits Novartis with the discovery and Incyte with development, licensed to Mirum Pharmaceuticals for commercialization. Clinically, the key value will now be durability across patient subsets, long-term safety, and real-world management of lesion prevention versus flare mitigation strategies.