Regeneron Prepares U.S. Submission for Garetosmab After Breakthrough Phase III Result in Ultra-Rare FOP

Regeneron’s garetosmab achieved a greater than 99% reduction in new bone lesion volume in adults with fibrodysplasia ossificans progressiva (FOP) in the Phase III OPTIMA trial, meeting its primary endpoint and demonstrating unprecedented efficacy in this ultra-rare genetic disease1 2 3 5.

Based on the robust data and favorable safety profile, the Independent Data Monitoring Committee recommended immediate transition of placebo recipients to garetosmab, underscoring the treatment’s clinical impact1 4.

Regeneron plans to submit a biologics license application for garetosmab to the FDA by the end of 2025; global regulatory submissions are anticipated in 20261 5 6 8.

No approved therapies currently exist for FOP, which affects an estimated 1 in 1.6 million people globally—making garetosmab a potential first-in-class, transformative therapy2 4.

A pivotal Phase III trial in adolescents and children with FOP (OPTIMA 2) is planned for initiation next year, aiming to expand the treatable patient population1 4.

The trial reported a 100% retention rate among patients, indicating strong satisfaction and tolerability, which supports potential high adherence if approved2.

Garetosmab is a fully human monoclonal antibody developed to inhibit Activin A, a key driver of pathological bone formation in FOP1 2.