The U.S. Food and Drug Administration approved Regeneron Pharmaceuticals’ garetosmab, branded as Pasatru, for adults with fibrodysplasia ossificans progressiva, a rare genetic disorder in which muscle, tendon and ligament tissue progressively turns into bone. In the 56-week Phase 3 OPTIMA trial involving 63 participants, CT scans showed that new heterotopic ossification lesions fell 94% with a 3 mg/kg dose and 90% with a 10 mg/kg dose versus placebo, while the 10 mg/kg dose reduced clinician-assessed flare-ups by 88%. Pasatru blocks Activin A and can be administered through monthly 60-minute intravenous infusions, including in home-care settings. The condition affects roughly 1 in 2 million people, with about 800 to 900 diagnosed cases worldwide; the median survival age is 56 and many patients require wheelchairs by age 30. The European Medicines Agency is reviewing the treatment, and Regeneron plans additional applications, including in Japan.