Winrevair Gets Nod From UK Regulators

The United Kingdom’s Medicines and Healthcare Products Regulatory Agency (MHRA) has given Merck the go-ahead to market its pulmonary arterial hypertension (PAH) drug Winrevair (sotatercept) within the United Kingdom. The approval marks the latest expansion of Winrevair’s footprint since its initial approval in the United States March 2024.

“Keeping patients safe and enabling their access to high quality, safe and effective medical products are key priorities for us,” Julian Beach, MBA, MHRA’s interim executive director of healthcare quality and access, said in a press release. “We’re assured that the appropriate regulatory standards for the approval of this medicine have been met.”

The authorization allows the therapy to be used in combination with other PAH therapies to improve exercise capacity in adults with PAH and “moderate or marked” physical activity limitations.

The UK approval follows the European Medicines Agency’s approval of the activin signaling inhibitor therapy in late August of last year. Merck is also in the process of seeking authorization in Japan, having submitted an application to Japanese regulators in November, according to a company press release.

Caroline Litchfield

In an October earnings call reviewing the company’s third-quarter earnings, Merck executives expressed optimism about Winrevair’s early performance. Chief financial officer Caroline Litchfield said the company had global sales of Winrevair of $149 million as of the third quarter. She said approximately 1,700 new patients in the United States received a prescription for Winrevair in the third quarter, bringing total new patient prescriptions to 3,700 since the drug was approved.

Litchfield said about 800 physicians had written a prescription for the therapy, with most of those prescribers coming from large academic centers or private practices.

“Physicians are continuing to prioritize the sickest patients, who have already been receiving multiple PAH therapies,” she noted.

Litchfield added that the company has also continued to make progress with payers, with the percentage of patients covered nearly doubling in the third quarter. She said the company was also in the process of securing reimbursement in more European countries.

Winrevair was approved on the strength of the phase 3 STELLAR trial, in which adults with functional class II or III PAH saw meaningful improvement in six-minute walking distance (6MWD) after taking Winrevair in combination with background therapy for 24 weeks. Patients in the trial who received Winrevair saw an improvement of 40.8 meters in the 6MWD test compared with patients in the placebo group. The company said Winrevair also reduced the risk of death or clinical worsening compared with placebo.

In addition, the company last month announced that it had halted its phase 3 ZENITH trial because of overwhelming efficacy. That trial was focused on high-risk patients with functional class III or IV disease and its primary outcome was time to first confirmed morbidity or mortality event, such as lung transplantation, death, or PAH-related hospitalization of at least 24 hours.

At an interim analysis, the improvement seen by patients in the Winrevair cohort was so significant that an independent monitoring committee made the recommendation to stop the trial and allow all participants to receive Winrevair as part of an open-label extension trial.

Merck acquired Winrevair as part of its 2021 acquisition of Acceleron Pharma. Sotatercept was Acceleron’s lead product and was in phase 3 trials at the time.