If approved by the European Commission, WINREVAIR will be the first activin signaling inhibitor therapy for PAH in Europe, offering a new treatment option for certain adults with this rare, progressive disease

Milestone highlights Merck’s focus on global filings to expand access to WINREVAIR and commitment to patients living with PAH

RAHWAY, N.J.--(BUSINESS WIRE)-- Merck (NYSE: MRK), known as MSD outside of the United States and Canada, announced today that the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMA) recommended the approval of WINREVAIR™ (sotatercept), in combination with other pulmonary arterial hypertension (PAH) therapies, for the treatment of PAH in adult patients with World Health Organization (WHO) Functional Class (FC) II to III, to improve exercise capacity. WINREVAIR was previously granted Priority Medicines (PRIME) and orphan designation by the EMA for the treatment of PAH. The European Commission (EC) will now review the CHMP recommendation, and the EC’s decision on the marketing authorization application of WINREVAIR in the EU, Iceland, Liechtenstein and Norway is expected in the third quarter of 2024.

“PAH is a progressive and debilitating rare disease,” said Dr. Joerg Koglin, senior vice president and head of general medicine, global clinical development, Merck Research Laboratories. “There is still a significant need for new therapies for patients. This positive opinion marks the first step toward expanding access to our first-in-class activin signaling inhibitor therapy, WINREVAIR, for eligible adults with PAH in Europe. We are pleased with the CHMP recommendation and look forward to the European Commission’s decision.”

WINREVAIR is administered once every 3 weeks as a single injection under the skin and may be administered by patients or caregivers with guidance, training and follow-up from a healthcare provider.

The CHMP recommendation is based on data from the Phase 3 STELLAR trial of WINREVAIR on top of background PAH therapy compared to background therapy alone. WINREVAIR demonstrated a statistically significant and clinically meaningful improvement in 6-minute walk distance, the study’s primary endpoint, and on multiple important secondary outcome measures, including reducing the risk of death from any cause or PAH clinical worsening events. These results were published in The New England Journal of Medicine.

“WINREVAIR is the first activin signaling inhibitor therapy and is proposed to modulate the vascular proliferation underlying PAH,” said Dr. Marius Hoeper, Hannover Medical School, Germany. “Based on the clinical benefits demonstrated in primary and secondary outcome measures in the Phase 3 STELLAR study, WINREVAIR has the potential to play a critical role in the treatment of appropriate adults with PAH. It is very encouraging that physicians in Europe may soon have a novel treatment option available that targets a new PAH treatment pathway.”

Through the CHMP recommendation, the EMA is the second regulatory body to recognize the potential of WINREVAIR in the treatment of PAH based on a review of pivotal efficacy and safety data. In March 2024, WINREVAIR (sotatercept-csrk) was approved by the U.S. Food and Drug Administration (FDA).

About STELLAR

The STELLAR study (NCT04576988) was a global, double-blind, placebo-controlled, multicenter, parallel-group clinical trial in which 323 patients with PAH (WHO Group 1 FC II or III) were randomized 1:1 to WINREVAIR (target dose 0.7 mg/kg) (n=163) or placebo (n=160) plus stable background therapy administered subcutaneously once every 3 weeks.

The most common PAH etiologies were idiopathic PAH (59%), heritable PAH (18%), and PAH associated with connective tissue diseases (CTD) (15%). Most participants were receiving either three (61%) or two (35%) background drugs for PAH, and 40% were receiving prostacyclin infusions. The mean time from PAH diagnosis was 8.8 years. Patients had a WHO FC II (49%) or III (51%) at baseline.

About WINREVAIR™ (sotatercept-csrk) for injection, for subcutaneous use, 45 mg, 60 mg

In the U.S., WINREVAIR is FDA-approved for the treatment of adults with pulmonary arterial hypertension (PAH, WHO Group 1) to increase exercise capacity, improve WHO functional class (FC) and reduce the risk of clinical worsening events. WINREVAIR, the first activin signaling inhibitor therapy approved to treat PAH, improves the balance between pro-proliferative and anti-proliferative signaling to modulate vascular proliferation. In preclinical models, WINREVAIR induced cellular changes that were associated with thinner vessel walls, partial reversal of right ventricular remodeling, and improved hemodynamics.

WINREVAIR is the subject of a licensing agreement with Bristol Myers Squibb.

Selected Safety Information for WINREVAIR in the U.S.

WINREVAIR may increase hemoglobin and lead to erythrocytosis. Severe erythrocytosis may increase the risk of thromboembolic events or hyperviscosity syndrome. Monitor Hgb before each dose for the first 5 doses, or longer if values are unstable, and periodically thereafter, to determine if dose adjustments are required.

WINREVAIR may decrease platelet count and lead to severe thrombocytopenia, which may increase the risk of bleeding; thrombocytopenia occurred more frequently in patients also receiving prostacyclin infusion. Do not initiate treatment if platelet count is