Merck Gains EU CHMP Approval for WINREVAIR™ in PAH

Merck & Co., also known as MSD outside the United States and Canada, has announced that the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMA) has recommended the approval of WINREVAIR™ (sotatercept) for the treatment of pulmonary arterial hypertension (PAH) in adult patients. If the European Commission approves it, WINREVAIR will become Europe's first activin signaling inhibitor therapy for PAH, providing a new treatment option for this rare and progressive disease.

Dr. Joerg Koglin of Merck Research Laboratories emphasized the significant need for new therapies in PAH treatment, describing the CHMP's recommendation as a pivotal step in making this groundbreaking therapy available to eligible adults across Europe. WINREVAIR, administered via a subcutaneous injection every three weeks, has demonstrated significant improvements in exercise capacity among PAH patients.

The recommendation from the CHMP is based on data from the Phase 3 STELLAR trial, which compared the efficacy of WINREVAIR combined with existing PAH therapies against background therapy alone. The trial showcased a statistically significant improvement in the primary endpoint of the six-minute walk distance. Furthermore, WINREVAIR showed a meaningful reduction in the risk of death from any cause or PAH-related clinical worsening events. These promising results were published in The New England Journal of Medicine.

Dr. Marius Hoeper from Hannover Medical School highlighted the potential impact of WINREVAIR on PAH treatment, noting its unique mechanism in modulating vascular proliferation. The clinical benefits observed in the STELLAR study suggest that WINREVAIR could play a crucial role in treating PAH and offer healthcare providers in Europe a novel treatment option targeting a new pathway in PAH therapy.

The EMA's recognition of WINREVAIR follows the U.S. Food and Drug Administration's approval in March 2024. The STELLAR study, a global, double-blind, placebo-controlled clinical trial, involved 323 PAH patients with WHO Functional Class II or III. Patients were randomized to receive either WINREVAIR or a placebo, alongside stable background therapy. The trial included various PAH etiologies, with idiopathic PAH being the most common. Most participants were already on multiple PAH treatments, with a significant portion receiving prostacyclin infusions.

WINREVAIR, the first activin signaling inhibitor therapy approved for PAH, aims to balance pro-proliferative and anti-proliferative signaling to modulate vascular proliferation. Preclinical models have shown that WINREVAIR can induce cellular changes associated with thinner vessel walls, partial reversal of right ventricular remodeling, and improved hemodynamics.

In the U.S., WINREVAIR is approved for increasing exercise capacity, improving WHO functional class, and reducing the risk of clinical worsening in adults with PAH. However, it comes with selected safety information, including potential risks like erythrocytosis, thrombocytopenia, and serious bleeding events, particularly in patients receiving prostacyclin background therapy or antithrombotic agents.

Pulmonary arterial hypertension is a rare, life-threatening disorder characterized by the constriction of small pulmonary arteries and elevated blood pressure in the pulmonary circulation. It affects approximately 40,000 people in the U.S. and 30,000 in the EU, leading to significant strain on the heart and reduced life expectancy. The five-year mortality rate for PAH is around 43%, based on data from the REVEAL registry.

Merck, a global biopharmaceutical company known for its innovative health solutions, aims to expand access to WINREVAIR and improve the lives of patients with PAH. The company's dedication to research and development is reflected in its efforts to bring new treatment options to patients worldwide.