Merck announced that the European Commission (EC) has approved Winrevair (sotatercept) for use in combination with other therapies to treat pulmonary arterial hypertension (PAH) in adult patients with World Health Organization (WHO) Functional Class II-III.
This approval is aimed at improving exercise capacity in patients and marks the first time an activin signaling inhibitor therapy has been approved for PAH across the 27 EU member states, as well as Iceland, Liechtenstein, and Norway.
Winrevair works by balancing pro-proliferative and anti-proliferative signals to regulate the abnormal cell growth in blood vessels that characterizes PAH. The approval from the EC is based on the successful results from the Phase 3 STELLAR trial.
STELLAR Trial Results
The Phase 3 STELLAR trial provided the foundation for the EC's approval, comparing the effectiveness of Winrevair (n=163) against a placebo (n=160), both used in conjunction with standard PAH therapies. The primary focus of the study was the change in the six-minute walk distance after 24 weeks of treatment. Patients receiving Winrevair demonstrated a significant improvement, walking an average of 40.8 meters more than those on placebo. Additionally, Winrevair significantly reduced the risk of death or clinical worsening, with an 82% reduction observed in the study.
Administration and Usage
Winrevair is administered as a single subcutaneous injection once every three weeks. Patients or caregivers can administer the injection themselves with appropriate guidance and training from healthcare professionals. The Instructions for Use provide detailed information on the proper preparation and administration of the injection.
Approval and Designations
Winrevair was previously granted Priority Medicines (PRIME) and orphan designation by the European Medicines Agency (EMA) for the treatment of PAH. On March 26, 2024, the FDA also approved Winrevair in the United States for treating adults with PAH to enhance exercise capacity, improve WHO functional class, and reduce the risk of clinical worsening events.
About the STELLAR Study
The STELLAR study was a global, double-blind, placebo-controlled trial involving 323 patients with PAH (WHO Group 1, FC II-III), who were randomly assigned to receive either Winrevair (n=163) or a placebo (n=160), in addition to their stable background therapy.
The most common forms of PAH in the study were idiopathic PAH (59%), heritable PAH (18%), and PAH associated with connective tissue diseases (15%). A significant portion of the participants were already on multiple PAH medications, with 61% receiving three drugs, 35% on two, and 40% on prostacyclin infusions. The average time since diagnosis was 8.8 years, with patients having WHO FC II (49%) or III (51%) at the start of the study.
About Winrevair (sotatercept)
Winrevair, the first approved activin signaling inhibitor for PAH, aims to rebalance the signals that regulate vascular proliferation. In preclinical studies, Winrevair was shown to induce changes in cells that led to thinner blood vessel walls, partial reversal of right ventricular remodeling, and improved blood flow dynamics, offering new hope for patients with PAH.
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