FDA Approves Pasatru for Adults With Fibrodysplasia Ossificans Progressiva

The U.S. Food and Drug Administration has authorized Pasatru (garetosmab-grts) for use in adults diagnosed with fibrodysplasia ossificans progressiva (FOP), a rare and progressive disorder.

According to the FDA, Pasatru is intended to help decrease the formation of new heterotopic ossification (HO) lesions and reduce flare-ups as assessed by clinicians in adult patients with FOP. The approval allows Regeneron Pharmaceuticals to manufacture and distribute the drug from its facility in Rensselaer, New York.

The FDA’s decision was based on data from the Phase 3 OPTIMA clinical trial. In this study, both 3 mg/kg and 10 mg/kg doses of Pasatru demonstrated a reduction in the development of new HO lesions over a 56-week period when compared to a placebo group.

Regeneron stated that the 3 mg/kg dose of Pasatru reduced new HO lesions by approximately 94%, with patients experiencing 1 lesion compared to 19 in the placebo group. The 10 mg/kg dose led to a reduction of about 90%, with 2 lesions observed versus 19 in the placebo group.

What the numbers show

• FDA approved Pasatru for adults with FOP on August 19, 2026.
• OPTIMA trial: 3 mg/kg dose reduced new HO lesions by 94%.
• OPTIMA trial: 10 mg/kg dose reduced new HO lesions by 90%.

Regeneron’s biologics license application for Pasatru was approved by the FDA, which authorizes both interstate commerce and manufacturing of the treatment in New York. The regulatory approval process followed the submission of clinical data demonstrating the drug’s efficacy in reducing new HO lesions in adults with FOP.

In parallel developments, Mirum Pharmaceuticals and Incyte announced that the FDA accepted the New Drug Application for zilurgisertib, another treatment candidate for FOP, under Priority Review. The Prescription Drug User Fee Act (PDUFA) target action date for this application is set for September 26, 2026.

Zilurgisertib is an investigational oral ALK2 inhibitor being developed for FOP, with Mirum holding worldwide development and commercialization rights through a license from Incyte. The pivotal Phase 2 PROGRESS study for zilurgisertib showed reductions in total HO lesion volume, new HO lesions, and flare activity in both adolescents and adults with FOP, with no new HO lesions observed during the open-label extension phase.

Both Pasatru and investigational treatments like zilurgisertib represent ongoing efforts to address the needs of patients living with FOP, with regulatory agencies reviewing clinical data to determine safety and efficacy for approval and potential future use.

* This article is based on publicly available information at the time of writing.