FDA updates Merck's Winrevair label with 76% risk cut

The US Food and Drug Administration approved an update to the product label for Merck's Winrevair (sotatercept-csrk) for injection, available in 45 mg and 60 mg doses. The update incorporates efficacy and safety data from the Phase 3 HYPERION trial evaluating adults newly diagnosed with pulmonary arterial hypertension (PAH) within 12 months.

In the 320-patient study, adding Winrevair to background therapy cut the risk of clinical worsening events by 76% compared to placebo (hazard ratio 0.24, p<0.0001). A first clinical worsening event occurred in 10.6% (17 of 160) of patients taking Winrevair versus 36.9% (59 of 160) of those on placebo. Participants enrolled at a mean of 7.2 months since diagnosis, with 72% on double background therapy and 28% on triple background therapy.

The label update also adds safety guidance. Winrevair is contraindicated in patients with serious hypersensitivity such as anaphylaxis or angioedema. Healthcare providers must monitor hemoglobin and platelet levels before each of the first 5 doses and periodically after that, as the drug can cause erythrocytosis or thrombocytopenia. In HYPERION, treatment discontinuation due to adverse events was 3% with Winrevair, mainly caused by epistaxis, compared to 0% with placebo.

Separately, earlier in September 2026, the European Respiratory Society issued clinical guidelines giving Winrevair a strong recommendation with high certainty of evidence as an add-on therapy for adults with PAH on background treatment who have not reached low-risk status.