Merck, known as MSD outside of the United States and Canada, today announced the first presentation of results from the Phase 3 ZENITH trial evaluating WINREVAIR™ (sotatercept-csrk) compared to placebo in adults with pulmonary arterial hypertension (PAH, Group 1 PH) WHO* functional class (FC) III or IV at high risk of mortality who were on maximum tolerated background PAH therapy. At a median follow-up of 10.6 months (range, 0.3-26.1), WINREVAIR reduced the relative risk of major morbidity and mortality events (the composite of all-cause death, lung transplantation and PAH worsening-related hospitalization of ≥24 hours) by 76% (HR=0.24 [95% CI, 0.13-0.43]; p<0.0001 [1-sided]) compared to placebo.