FDA Approves Merck’s Drug for Pulmonary Arterial Hypertension

The FDA has approved Winrevair (sotatercept-csr), Merck’s therapy to treat adults with pulmonary arterial hypertension (PAH).

Pulmonary arterial hypertension is a rare, progressive and life-threatening disease in which blood vessels in the lungs narrow, causing strain on the heart. About 40,000 people in the United States are living with PAH. The five-year mortality rate is about 43%.

PAH is caused by the growth of cells in the arterial walls in the lung, leading to narrowing and abnormal constriction. Winrevair is a first-in-class activin signaling inhibitor. It is given once every three weeks by subcutaneous injection. Merck officials said in a press release that Winrevair will be available through select specialty pharmacies in the United States by the end of April.

The price of Winrevair is $14,000 per vial, and Merck officials said they expect patients will be mostly in Medicare and Medicaid patients. About a third or more of patients are expected in commercial plans.

Related: FDA Approves Combination Therapy for Pulmonary Arterial Hypertension

This is the second approval in two days for a treatment for patients with pulmonary arterial hypertension. The FDA just approved Johnson & Johnson’s Opsynvi, a single-tablet combination of macitentan, an endothelin receptor antagonist (ERA), and tadalafil, a phosphodiesterase 5 (PDE5) inhibitor. Macitentan is sold by J&J under the name of Opsumit. The list price of Opsynvi will be at parity to Opsumit, according to a spokesperson for J&J, and patients won’t have to pay any out-of-pocket costs related to separate PDE5 inhibitor prescription. The cost for Opsumit oral tablet 10 mg is around $6,662 for a supply of 15 tablets, according to Drugs.com.

The approval of Winrevair is based on the results of the STELLAR phase 3 trial. In the trial, Winrevair given with a background therapy demonstrated a statistically significant and clinically meaningful improvement in six-minute walk distance and eight of nine secondary outcome measure. Data were presented earlier last year at the American College of Cardiology meeting and published in the New England Journal of Medicinein April 2023. In the trial, 38.9% of patients in the Winrevair group achieved improvement at week 24 compared with 10.1% in the placebo group.

In September 2023, Merck presented an additional analysis from the STELLAR study and interim results from the open-label SOTERIA study at the European Respiratory Society International Congress 2023. An exploratory post-hoc analysis of right heart catheterization and echocardiography data from patients in the STELLAR study showed treatment with Winrevair reduced right heart size and improved right-ventricular function and hemodynamic status.