The FDA approved Regeneron’s Pasatru (garetosmab) to treat fibrodysplasia ossificans progressiva (FOP), clearing a new option for patients with the rare degenerative condition that causes muscle and connective tissue to turn into bone. Regeneron said Pasatru reduces new abnormal bone formations by 90% or more versus placebo over a year, based on Phase 3 results. Pasatru enters a crowded competitive landscape against Ipsen’s Sohonos (approved in 2023). While head-to-head data are not available, regulatory concerns previously centered on potential inflammatory “flare-ups” for patients treated with Sohonos. With an estimated average annual list price of roughly $1.4 million per patient, the approval is likely to shape commercial dynamics in ultra-rare immunology/orthopedic oncology-adjacent care while placing renewed attention on payer access and safety monitoring for this population.