In HYPERION, in patients diagnosed with PAH in the last 12 months, adding WINREVAIR on top of background therapy reduced the risk of clinical worsening events compared to placebo, informing the use of WINREVAIR earlier in the treatment journey

Newly published European Respiratory Society (ERS) clinical guidelines provide updated evidence-based recommendations for the treatment of PAH

Merck (NYSE:MRK), known as MSD outside of the United States and Canada, today announced the U.S. Food and Drug Administration (FDA) has approved an update to the U.S. product label for WINREVAIR™ (sotatercept-csrk) for injection, 45mg, 60mg, based on the Phase 3 HYPERION trial. WINREVAIR, an activin signaling inhibitor, is FDA-approved for the treatment of adults with pulmonary arterial hypertension (PAH, WHO Group 1 pulmonary hypertension) to improve exercise capacity and WHO functional class (FC), and reduce the risk of clinical worsening events, including hospitalization for PAH, lung transplantation and death. Today’s approval updates the WINREVAIR label to include efficacy and safety data from the HYPERION trial evaluating adults newly diagnosed with PAH (WHO FC II or III, diagnosed within 12 months of study screening) at intermediate to high risk of disease progression, providing insights into the role of WINREVAIR when added to background therapy within the first year of a PAH diagnosis.

In HYPERION (N=320; 160 WINREVAIR, 160 placebo), adding WINREVAIR to background therapy reduced the risk of clinical worsening events by 76% in adults with PAH WHO functional class II or III compared to placebo (hazard ratio [HR] 0.24; [95% confidence interval [CI], 0.14 to 0.41]; p<0.0001). The primary composite endpoint, time to death or first confirmed morbidity event, included all-cause death, unplanned PAH-related hospitalization lasting ≥24 hours, atrial septostomy, lung transplantation or a decrease in 6-minute walk distance (6MWD) from baseline combined with at least one of the following: worsening of WHO FC, signs or symptoms of increased right heart failure, or addition or change of a background PAH therapy. A first clinical worsening event occurred in 10.6% (17 of 160) of patients who received WINREVAIR and 36.9% of patients (59 of 160) who received placebo. The trial enrolled participants within their first year of diagnosis (mean time since PAH diagnosis was 7.2 months), with 72% of participants on double background therapy and 28% on triple background therapy; 17% of participants were on prostacyclin infusion therapy. The treatment effect was consistent across all prespecified subgroups (identified below) treated with WINREVAIR.