Regeneron secures FDA approval for Pasatru, second U.S. treatment for rare bone disease FOP

Regeneron received FDA approval for its antibody garetosmab, marketed as Pasatru, for treatment of fibrodysplasia ossificans progressiva (FOP) in adults.

The approval makes Pasatru the second therapy cleared in the United States for this ultrarare condition, following Ipsen’s Sohonos, which was approved in 2023 after a troubled development path.

Pasatru is indicated to reduce the formation of new heterotopic ossification lesions and clinician‑assessed flare‑ups, offering a new commercial product for Regeneron and setting up direct competition with Ipsen’s existing FOP drug.

Ipsen’s Sohonos contributed €11.4 million in sales in the first half of 2026, while the company recently faced a $728 million hit after pausing dosing in its palovarotene trials.