Sotatercept Takes Step Forward with European Regulators

Merck and Co.’s sotatercept (Winrevair) has made a significant step toward approval in Europe, as the European Medicines Agency’s (EMA) Committee for Medicinal Products for Human Use (CHMP) last month recommended approval of the pulmonary arterial hypertension (PAH) drug.

The recommendation calls for the drug to be approved for adult patients with World Health Organization (WHO) Functional Class II to III disease, in combination with other PAH therapies.

“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,” said Joerg Koglin, M.D., Ph.D., Merck’s senior vice president for global clinical development, in a press release.

The development in Europe is part of a strategy by Merck to quickly expand access to the potential blockbuster drug around the globe.

Merck’s sotatercept application will now go before the European Commission for a final decision on whether to authorize the marketing of the drug in Europe.

Sotatercept gained approval from the FDA in March 2024 on the strength of the phase 3 STELLAR trial. In that study, 163 patients with WHO class II or III who were randomized to receive sotatercept achieved a median improvement of 34.4 meters in their six-minute walking distance (6MWD) tests after 24 weeks. Patients in the placebo group had a median improvement of just one meter. Adverse events that were seen more commonly in the sotatercept group were epistaxis, dizziness, telangiectasia, increased hemoglobin levels, thrombocytopenia, and increased blood pressure, the study found.

Marius Hoeper, M.D.

Study co-author Marius Hoeper, M.D., of Hannover Medical School, in Germany, praised the CHMP’s decision in the press release.

“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,” Hoeper said. “It is very encouraging that physicians in Europe may soon have a novel treatment option available that targets a new PAH treatment pathway.”

The exact population of people with PAH in Europe is not known. However, a 2021 review of existing country-level literature suggested a prevalence as high as 47.6 patients per million people in Sweden and 45.7 patients per million people in Latvia and as low as 15 patients per million in France and 16 patients per million in Spain. However, the studies generating those data in France and Spain are both more than 15 years old.

Sotatercept is the first FDA-approved activin signaling inhibitor therapy for PAH. According to the company, it works by improving “the balance between pro-proliferative and anti-proliferative signaling to modulate vascular proliferation.” It is administered subcutaneously every three weeks.

Merck attained the drug in 2021 as part of its acquisition of Acceleron Pharma, Inc.

The EMA committee had already granted sotatercept priority medicine and orphan drug status for sotatercept. The priority designation provides “early and enhanced” reviews to therapies that have the potential to fill unmet medical needs.

Merck said it expects the European Commission to rule on the company’s marketing application soon—in the third quarter of this year. The decision will impact the drug’s availability in the European Union, as well as in Iceland, Liechtenstein, and Norway.

If the European Commission eventually grants its approval, the approval will stand market-wide, according to the EMA. However, decisions about pricing and reimbursement will be made on a country-by-country basis, the agency said.