FDA Grants Priority Review To Merck’s WINREVAIR Label Update Based On ZENITH Trial

Merck has announced that the U.S. FDA has accepted and granted priority review to a supplemental Biologics License Application (sBLA) for WINREVAIR™ (sotatercept-csrk). The application seeks to update the U.S. label based on positive Phase 3 ZENITH trial results in adults with pulmonary arterial hypertension (PAH). A target decision date (PDUFA) has been set for October 25, 2025.

The ZENITH trial was the first Phase 3 PAH study to use a primary endpoint solely based on major morbidity and mortality outcomes and was halted early due to overwhelming efficacy. WINREVAIR showed a 76% reduction in risk for a composite outcome of all-cause death, lung transplantation, and ≥24-hour PAH hospitalization compared to placebo.

“We are pleased that the FDA has accepted our sBLA for WINREVAIR and granted a priority review to consider an update to labeling for WINREVAIR to include the impressive results of ZENITH. There remains a significant unmet medical need for patients living with PAH who, despite being on background therapy, remain at higher risk of morbidity and mortality. The FDA’s Priority Review designation acceptance of our sBLA reinforces our confidence in WINREVAIR for a broad range of patients and represents a critical step toward advancing the treatment of PAH,” said Dr. Joerg Koglin, senior vice president, global clinical development, Merck Research Laboratories. 

Already approved in over 45 countries, WINREVAIR’s expanded U.S. label would reflect its robust efficacy and safety profile demonstrated in both the ZENITH and STELLAR trials. The drug has shown meaningful improvements in exercise capacity and disease progression among PAH patients.