Merck reports ‘positive’ results from Phase 3 HYPERION trial of winrevair

Merck (MRK) announced positive results from the Phase 3 HYPERION trial evaluating WINREVAIR versus placebo in recently diagnosed adults with pulmonary arterial hypertension functional class II or III at intermediate or high risk of disease progression. In the study, WINREVAIR reduced the risk of clinical worsening events by 76% as measured by a composite endpoint of all-cause death, the need for non-planned PAH-related hospitalization greater than or equal to24 hours, atrial septostomy, lung transplantation or PAH deterioration. HYPERION included participants who were within their first year of diagnosis, with over 70% of trial participants on double background therapy. In the pivotal Phase 3 study, STELLAR, participants were WHO Group 1, FC II or III at baseline and had an average disease duration of 8.8 years from PAH diagnosis to screening. The safety profile of WINREVAIR was generally consistent with that observed in previous trials. Results from the study were presented today at the 2025 European Respiratory Society Congress and simultaneously published in the New England Journal of Medicine.