REGN Phase 2 readout: a negative outcome, -9.8%

On May 18, 2026, Garetosmab — Regeneron Pharmaceuticals, Inc. (Fibrodysplasia Ossificans Progressiva) reached its Phase 2 readout. The result was a negative outcome, and the stock moved -9.8% in the window around the event. It had already run -7.0% in the 30 days into the catalyst — the kind of pre-event run-up that often precedes binary readouts.