The U.S. Food and Drug Administration announced Wednesday that it has approved Regeneron’s new medication, garetosmab, marketed under the brand name Pasatru, for the treatment of adults with fibrodysplasia ossificans progressiva (FOP). FOP is a rare genetic disorder in which muscle, tendon and ligament tissue gradually ossify, creating a second skeleton that severely limits mobility and shortens life expectancy.
Clinical trial results
In a 56‑week, placebo‑controlled trial involving 63 participants, Pasatru demonstrated a dramatic reduction in new bone formation. Patients receiving a dose of 3 mg per kilogram experienced a 94 % decrease in abnormal bone growth, while those given 10 mg per kilogram saw a 90 % reduction compared with placebo. The drug works by blocking Activin A, a protein that triggers the pathological bone growth seen in FOP patients.
Regeneron’s next steps
Regeneron’s clinical team member Susan Rhee told Reuters that the company plans to begin a trial in children later this year, expanding the potential patient population. The company previously paused dosing in a mid‑stage trial after five patient deaths in 2020, subsequently discontinuing that study and working with regulators to redesign the late‑stage trial.
Market landscape
Pasatru will join French drugmaker Ipsen’s oral therapy Sohonos, which received FDA approval in 2023 as the only other treatment for FOP. Additional candidates are in development, including programs from Incyte with partner Mirum Pharma and privately held Ashibio.
Impact on the rare‑disease community
FOP affects roughly one in two million people worldwide, with an estimated 800 to 900 active diagnosed cases globally, according to the National Institutes of Health. The approval of Pasatru offers a new therapeutic option for a condition that has long lacked effective treatments, providing hope to patients and families confronting a progressive loss of mobility.
Regeneron’s market response
Following the FDA announcement, Regeneron’s shares rose 4 % in after‑hours trading, reflecting investor optimism about the drug’s commercial potential.
Original reporting: Appleton, WI News Feed (HLL/CB) — read the source article.
