RAHWAY, N.J.–(BUSINESS WIRE)–Merck (NYSE: MRK), known as MSD outside of the United States and Canada, today announced the U.S. Food and Drug Administration (FDA) has approved an update to the U.S. product label for WINREVAIR™ (sotatercept-csrk) for injection, 45mg, 60mg, based on the Phase 3 HYPERION trial. WINREVAIR, an activin signaling inhibitor, is FDA-approved for the treatment of adults with pulmonary arterial hypertension (PAH, WHO Group 1 pulmonary hypertension) to improve exercise ca