WINREVAIR (sotatercept-csrk) - (HYPERION)

September 22, 2026: Merck (NYSE: MRK) said the FDA approved a U.S. label update for WINREVAIR (sotatercept-csrk) in pulmonary arterial hypertension (PAH, WHO Group 1), adding Phase 3 HYPERION efficacy and safety data in adults diagnosed within 12 months and on background therapy.

In HYPERION (N=320), WINREVAIR plus background therapy reduced the risk of clinical worsening events by 76% versus placebo (HR 0.24, 95% CI 0.14-0.41; p<0.0001). First clinical worsening events occurred in 10.6% (17/160) of WINREVAIR patients versus 36.9% (59/160) on placebo. The primary endpoint was time to death or first confirmed morbidity event, including all-cause death, PAH hospitalization, atrial septostomy, lung transplantation, or decline in 6-minute walk distance with other worsening criteria. The company said treatment effect was consistent across prespecified subgroups.

HYPERION adverse events were generally consistent with STELLAR. The most common adverse reactions were epistaxis (31.9% vs 6.9%), telangiectasia (26.3% vs 11.3%), and increased hemoglobin (11.3% vs 1.3%); discontinuation due to adverse events was 3% vs 0%.

Merck also noted newly published ERS PAH guidelines gave WINREVAIR a “strong” recommendation for adults on background therapy who have not achieved low-risk status.