Why Regeneron (REGN) Is Up 5.4% After FDA Approves Pasatru For Ultra-Rare FOP Therapy

In August 2026, Regeneron Pharmaceuticals announced that the US FDA approved Pasatru (garetosmab-grts) to reduce new heterotopic ossification lesions and flare-ups in adults with fibrodysplasia ossificans progressiva, based on positive Phase 3 OPTIMA trial results. This approval adds a rare-disease monoclonal antibody to Regeneron’s portfolio, reinforcing the company’s focus on specialized, high-complexity immunology therapies. We’ll now examine how Pasatru’s FOP approval, as an ultra-rare...