RAHWAY, N.J. — September 22, 2026
Merck announced that the U.S. Food and Drug Administration (FDA) has approved an update to the WINREVAIR™ (sotatercept-csrk) label to incorporate efficacy and safety data from the Phase 3 HYPERION trial in adults recently diagnosed with pulmonary arterial hypertension (PAH), WHO Group 1 pulmonary hypertension. The updated label provides data for patients diagnosed with PAH within the previous 12 months who were receiving background therapy and had intermediate to high risk of disease progression. WINREVAIR is an activin signaling inhibitor already approved in the US to improve exercise capacity and WHO functional class and reduce the risk of clinical worsening events in adults with PAH.
HYPERION Demonstrates Reduced Risk of Clinical Worsening
In the Phase 3 HYPERION trial, 320 adults with newly diagnosed PAH were randomized to receive WINREVAIR or placebo in addition to background therapy. Adding WINREVAIR reduced the risk of the trial’s composite clinical worsening endpoint by 76% compared with placebo, with a hazard ratio of 0.24 (95% CI, 0.14-0.41; p<0.0001). A first clinical worsening event occurred in 10.6% of patients receiving WINREVAIR compared with 36.9% receiving placebo. The primary endpoint included death, unplanned PAH-related hospitalization, atrial septostomy, lung transplantation or a clinically relevant decline in six-minute walk distance accompanied by additional indicators of disease worsening. Participants had been diagnosed for a mean of 7.2 months, with 72% receiving double background therapy and 28% receiving triple therapy.
HYPERION Expands Evidence for Earlier PAH Treatment
The HYPERION findings provide clinical evidence for the use of WINREVAIR within the first year following a PAH diagnosis when added to background therapy. The treatment effect was consistent across prespecified subgroups, including patients receiving double or triple background therapy and those receiving prostacyclin infusion therapy. The most common adverse reactions in HYPERION occurring in at least 10% of WINREVAIR-treated patients and at least 5 percentage points more frequently than placebo were epistaxis, telangiectasia and increased hemoglobin. Treatment discontinuation because of adverse events occurred in 3% of WINREVAIR-treated patients and no placebo-treated patients. The updated label also includes warnings concerning serious hypersensitivity reactions, erythrocytosis, thrombocytopenia, bleeding and embryo-fetal toxicity.
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Merck Advances WINREVAIR Clinical Development in PAH
The HYPERION results add to the Phase 3 evidence base for WINREVAIR, following the STELLAR and ZENITH trials. HYPERION was a global, double-blind, placebo-controlled study of adults with WHO functional class II or III PAH diagnosed within 12 months and at intermediate to high risk of disease progression. The updated US label comes alongside newly published European Respiratory Society clinical guidelines for PAH, which incorporate evidence for WINREVAIR in treatment recommendations. Merck continues to evaluate WINREVAIR as part of its broader PAH development program, while the FDA label update provides additional information for healthcare professionals considering treatment options for adults earlier in the course of PAH.
Source :Merck press release
