Merck Winrevair (Sotatercept-csrk) Pulmonary Arterial Hypertension Label Expansion PDUFA Target Date September 21, 2026
Merck (NYSE: MRK) awaits its September 21, 2026 PDUFA target action date for a further label expansion of Winrevair (sotatercept-csrk, an activin signaling inhibitor administered as subcutaneous injection every three weeks) in pulmonary arterial hypertension (PAH). Winrevair was originally FDA-approved March 26, 2024 for adults with PAH (WHO Group 1) to increase exercise capacity, improve WHO functional class, and reduce risk of clinical worsening events, based on the Phase 3 STELLAR trial. The pending label expansion is expected to cover an earlier line of therapy and/or a broader patient population based on the ZENITH and HYPERION Phase 3 trials that reported earlier in 2026 (ZENITH: PAH high-risk patients on maximal background therapy; HYPERION: newly diagnosed PAH). The Winrevair franchise reached $260 million in Q2 2026 revenue and is on track to reach $1 billion annual run rate before end of 2026. Sotatercept-csrk is a fusion protein of activin receptor type IIA and the Fc portion of human immunoglobulin.