Biologic Winrevair Wins FDA Approval for Treatment of PAH

The US Food and Drug Administration has approved the injectable biologic sotatercept-csrk (Winrevair) for the management of adults with pulmonary arterial hypertension (PAH), drugmaker Merck announced late Tuesday.

Winrevair belongs to a new class of therapy known as activin signaling inhibitors and is the first of this class to be approved by the FDA for PAH. The drug works by enhancing the balance between pro- and antiproliferative signaling pathways.

The approval is based on data from the STELLAR trial, which compared Winrevair to placebo in adult patients with PAH (WHO Group 1 FC II or III). Compared with placebo and background therapy alone, the addition of Winrevair to background therapy increased 6-minute walk distance over 24 weeks and was associated with lower risk of all-cause death and nonfatal clinical worsening of PAH.

STELLAR also showed that sotatercept-csrk was well tolerated, with the fewer serious adverse events than in the placebo arm. However, the drug can increase hemoglobin and lead to erythrocytosis. It also may increase the risk of thromboembolic events or hyperviscosity syndrome as well as decrease platelet count. For these reasons, healthcare providers “should monitor hemoglobin and platelets before each dose of Winrevair for the first five doses, or longer if values are unstable, and periodically thereafter to determine if dose adjustments are required,” Merck said in a press release announcing the approval.

In the STELLAR trial, the most common adverse reactions in patients on Winrevair were headache, epistaxis, rash, telangiectasia, diarrhea, dizziness, and erythema.

Winrevair is available in 45-mg and 60-mg injections and is intended to be administered once every 3 weeks by patients or caregivers under the guidance of healthcare providers with appropriate follow-up. According to Merck, it should be available on pharmacy shelves by the end of April.

The approval comes on the heels of another win for patients with PAH: last week's announcement of a single-tablet combination of macitentan, an endothelin receptor antagonist (ERA), and tadalafil, a phosphodiesterase 5 inhibitor (PDE5i). The FDA's approval of Opsynvi (Johnson & Johnson) was based on data from the phase III A DUE pivotal trial.