FDA Expands Merck's Winrevair Indication for Pulmonary Arterial Hypertension

Strategic Insights -

The US Food and Drug Administration (FDA) has approved an updated indication for Winrevair (sotatercept-csrk) to treat adults with pulmonary arterial hypertension (PAH, WHO Group 1), based on results from the Phase 3 ZENITH trial. The approval expands the label to include reductions in key clinical worsening events such as hospitalisation for PAH, lung transplantation, and death. The ZENITH study enrolled 172 participants and demonstrated a 76% reduction in the risk of major morbidity and mortality compared to placebo.

Key Takeaways:

  • The FDA has approved an updated indication for Winrevair to treat adults with pulmonary arterial hypertension (PAH, WHO Group 1) based on results from the Phase 3 ZENITH trial.
  • The approval expands the label to include reductions in key clinical worsening events such as hospitalisation for PAH, lung transplantation, and death.
  • In the ZENITH study, adding Winrevair to background therapy reduced the risk of major morbidity and mortality by 76% compared to placebo.
  • The composite primary endpoint of time to first occurrence of all-cause death, lung transplantation, or hospitalisation for PAH occurred in 17% of Winrevair-treated patients versus 55% of those on placebo.
  • Winrevair was first approved in March 2024 following the STELLAR study, and the ZENITH data further support the therapy's benefit-risk profile across a broad range of adult patients with PAH.
  • Healthcare providers are advised to monitor haemoglobin and platelet levels during treatment due to potential risks of erythrocytosis and thrombocytopenia.
  • The most common adverse reactions included infections, epistaxis, diarrhoea, and telangiectasia.

Statistics:

  • 172 participants enrolled in the ZENITH study
  • 76% reduction in the risk of major morbidity and mortality compared to placebo
  • 17% of Winrevair-treated patients experienced the composite primary endpoint of time to first occurrence of all-cause death, lung transplantation, or hospitalisation for PAH
  • 55% of placebo-treated patients experienced the composite primary endpoint
  • March 2024: Winrevair was first approved following the STELLAR study

Sources:

  • M2 EQUITYBITES-Oct 27, 2025
  • "FDA expands Merck's Winrevair indication for pulmonary arterial hypertension based on Phase 3 trial results"
  • http://www.m2.co.uk
  • Merck & Co Inc (NYSE:MRK)
  • US Food and Drug Administration (FDA)