Winrevair cuts risk of PAH progression by 76% in phase 3 Hyperion trial

Hyperion results presented at ERS 2025 and simultaneously published in the New England Journal of Medicine

Merck announced positive results from the Phase 3 Hyperion trial evaluating Winrevair in combination with background therapy compared with placebo in recently diagnosed adults with pulmonary arterial hypertension (PAH, WHO Group 1), functional class (FC) II or III at intermediate or high risk of disease progression.

In the study, Winrevairreduced the risk of clinical worsening events by 76 per cent as measured by a composite endpoint of all-cause death, non-planned PAH-related hospitalization of at least 24 hours, atrial septostomy, lung transplantation, or PAH deterioration.

Patients were enrolled within their first year of diagnosis (median seven months, as early as one month), with more than 70 per cent receiving double background therapy. By comparison, participants in the pivotal Phase 3 STELLAR study had an average disease duration of 8.8 years at baseline.

“PAH is a rare condition that can progress rapidly, making timely diagnosis and early treatment critically important,” said Dr. Vallerie McLaughlin, Kim A. Eagle MD Endowed Professor of Cardiovascular Medicine and Director of the Pulmonary Hypertension Program at the University of Michigan. “The patients enrolled in Hyperion reflect the type of individuals we see in contemporary practice—older, with co-morbidities and early in their treatment journey. These compelling results demonstrate that initiating Winrevair within the first year of diagnosis, alongside background therapy, significantly reduces the risk of clinical worsening events.”

“These results expand the body of clinical evidence for Winrevair, showing robust efficacy in patients early in their PAH journey,” said Dr. Joerg Koglin, senior vice president, head of general and specialty medicine, global clinical development, Merck Research Laboratories. “The totality of Winrevair data continues to reinforce our confidence in its practice-changing potential. We thank the study participants and investigators for their invaluable contributions to this important trial.”

The safety profile of Winrevair in Hyperion was generally consistent with previous studies. Median follow-up was 14.6 months for patients receiving Winrevair compared with 11.5 months for those on placebo. Adverse events occurred in 89.4 per cent versus 90.0 per cent and serious adverse events in 24.4 per cent versus 28.1 per cent of participants in the Winrevair and placebo groups, respectively.