Merck, known as MSD outside of the United States and Canada, announced that the European Medicines Agency’s Committee for Medicinal Products for Human Use (CHMP) recommended the approval of an expanded indication for WINREVAIR™ (sotatercept), in combination with other pulmonary arterial hypertension (PAH) therapies, for the treatment of PAH in adult patients with WHO Functional Class (FC) II, III, and IV based on the Phase 3 ZENITH study. The currently approved indication in the European Union (EU) is for adults with PAH with WHO FC II to III, to improve exercise capacity. The CHMP recommendation will now be reviewed by the European Commission (EC) for amending the marketing authorization in the EU, Iceland, Liechtenstein and Norway, and a final decision is expected in the first quarter of 2026.
"If approved, this broader indication would recognize the impact of WINREVAIR on morbidity and mortality in adult patients with PAH, extending the overall use of WINREVAIR to be inclusive of WHO FC II, III and now IV patients, with a treatment objective beyond the improvement of exercise capacity,” said Dr. Joerg Koglin, senior vice president and head of general medicine, global clinical development, Merck Research Laboratories. “We look forward to the EC's decision as we work to ensure broad patient access to the first and only activin signaling inhibitor therapy approved in Europe and continue to deliver meaningful evidence to support treatment decisions.”
The CHMP recommendation is based on data from the Phase 3 ZENITH trial which demonstrated that adding WINREVAIR to background therapy resulted in a statistically significant and clinically meaningful 76% reduction in the risk of major morbidity and mortality outcomes, the study’s primary endpoint, in adults with PAH WHO functional class III or IV compared to placebo (HR: 0.24; 95% CI: 0.13, 0.43; p<0.0001). The trial’s composite primary efficacy endpoint — time to first occurrence of all-cause death, lung transplantation or PAH-worsening hospitalization of ≥24 hours — occurred in 15 WINREVAIR-treated participants (17%) versus 47 placebo-treated participants (55%). Due to overwhelming efficacy based on the primary endpoint result, the ZENITH trial was stopped early at the interim analysis and patients were offered the opportunity to receive WINREVAIR through an open-label long-term follow-up study. These results were published in the New England Journal of Medicine. The CHMP also reviewed morbidity and mortality outcomes data from the secondary endpoint of the pivotal Phase 3 STELLAR trial as part of this recommendation.
WINREVAIR is the first and only activin signaling inhibitor therapy for PAH approved in all 27 member states of the EU, as well as Iceland, Liechtenstein and Norway, and is currently approved in more than 50 countries. In October 2025, the U.S. Food and Drug Administration (FDA) approved an updated indication based on the Phase 3 ZENITH trial. WINREVAIR is now approved in the U.S. for the treatment of adults with PAH (WHO Group 1 pulmonary hypertension [PH]) to improve exercise capacity and WHO FC, and reduce the risk of clinical worsening events, including hospitalization for PAH, lung transplantation and death.
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