Merck says Phase 3 HYPERION study of WINREVAIR met primary endpoint

Merck (MRK) announced topline results from the Phase 3 HYPERION study 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. HYPERION met its primary endpoint of time to clinical worsening as measured by a composite endpoint of all-cause death, the need for non-planned PAH-related hospitalization greater than 24 hours, atrial septostomy, lung transplantation, or PAH deterioration. In HYPERION, WINREVAIR added on top of background therapy within 12 months after initial diagnosis of PAH demonstrated a statistically significant and clinically meaningful reduction in the risk of clinical worsening events when compared to placebo. HYPERION is the third Phase 3 study of WINREVAIR to demonstrate significant efficacy in adults with PAH. The first was the STELLAR study previously presented at ACC.23, followed by the ZENITH study presented at ACC.25. In contrast to HYPERION, these previous studies included a patient population where a majority of participants were on triple therapy. The safety profile of WINREVAIR was generally consistent with that observed in previous studies. As announced in January, HYPERION was stopped early and moved to final analysis based on the positive results from the interim analysis of the Phase 3 ZENITH trial and a review of the totality of data from the WINREVAIR clinical program to date, and all patients were offered the opportunity to receive WINREVAIR through the SOTERIA open-label extension study. “PAH is a progressive and debilitating disease with a poor prognosis that can be difficult to diagnose and treat. Patients often struggle for years to find a treatment plan that helps manage the disease, so it’s critical to provide new options earlier in the treatment journey,” said Dr. Vallerie McLaughlin, Kim A Eagle MD Endowed Professor of Cardiovascular Medicine and Director, Pulmonary Hypertension Program, University of Michigan in Ann Arbor. “The HYPERION study demonstrated that WINREVAIR on top of background therapy met its primary outcome measure of reduction in the time to clinical worsening events in adults who have been recently diagnosed with PAH. WINREVAIR has brought significant optimism to patients, their families and investigators and we thank all study participants for being part of this important study.” Results from HYPERION will be presented at an upcoming medical meeting later this year and will be submitted to regulatory authorities. WINREVAIR is currently approved in more than 45 countries based on the results from the STELLAR study.