Merck’s WINREVAIR Trial Shows Promising Outcomes For Treating PAH Patients

Merck, operating as MSD outside the U.S. and Canada, announced promising Phase 3 ZENITH trial results for WINREVAIR (sotatercept-csrk), a pulmonary arterial hypertension (PAH) treatment. The trial focused on adults with functional class (FC) III or IV PAH who face a high risk of mortality. WINREVAIR met its primary goal by significantly reducing the time to the first morbidity or mortality event, such as death, lung transplantation, or PAH-related hospitalisation lasting 24 hours or more. These results, achieved alongside standard PAH therapies, showed a meaningful decrease in the risk of such events compared to placebo.

Due to the strong outcomes, an independent data monitoring committee recommended early trial termination. This will allow participants to transition to the SOTERIA open-label extension study. Initial evaluations found the balance of adverse and severe events to be similar across treatment groups.

Dr. Eliav Barr, senior vice president and head of global clinical development, chief medical officer, Merck Research Laboratories, said in a statement, “PAH is a serious, progressive disease with a high incidence of morbidity and mortality. Based on the primary endpoint demonstrating overwhelming efficacy, all ZENITH study participants will be offered the opportunity to receive WINREVAIR. These impressive findings set a high evidentiary bar for studies of future candidates developed for the treatment of PAH and support the potential of WINREVAIR to be practice-changing in the management of PAH.”

WINREVAIR has already been approved in the U.S., and Phase 3 STELLAR trial findings support 36 other countries. In November, Merck sought regulatory approval in Japan, building on data from the STELLAR trial and a Phase 3 study specific to Japanese patients. Detailed ZENITH results will be shared at an upcoming medical conference and submitted to regulatory bodies for further review.

Dr Vallerie McLaughlin, Kim A Eagle MD Endowed Professor of Cardiovascular Medicine and Director, Pulmonary Hypertension Program, University of Michigan in Ann Arbor, commented, “The ZENITH trial was designed to evaluate whether the addition of WINREVAIR, an activin signalling inhibitor, could reduce the risk of death, lung transplantation, or PAH hospitalisations for patients living with advanced PAH.”

She also said, “This is the first study in PAH in which the interim analysis led to an early conclusion of the study due to overwhelming efficacy. WINREVAIR has brought significant optimism to the field, and we thank the investigators and patients for being part of this important study.”