According to Zhitong Finance APP, Merck (MRK.US) announced today that its "first-in-class" therapy Winrevair (sotatercept) achieved its primary endpoint in the interim analysis of the Phase 3 clinical trial ZENITH. Based on this positive result, the trial will be terminated early, allowing all patients with pulmonary arterial hypertension (PAH) the opportunity to receive Winrevair treatment. It is worth mentioning that this therapy has been rated by industry media Evaluate as one of the potential blockbuster therapies expected to be approved in 2024.

PAH is a rare progressive disease that occurs when the small arteries in the lungs thicken and narrow, leading to increased pressure in these arteries, putting stress on the heart. The occurrence of PAH involves three related processes, including inflammation, cell proliferation, and fibrosis, which play an important role in the thickening, narrowing, and stiffness of small pulmonary arteries, commonly referred to as "vascular remodeling." Currently approved PAH therapies mainly act as vasodilators to open the blood vessels, but these treatments cannot reverse the vascular remodeling caused by inflammation, proliferation, and fibrosis.

Winrevair is a "first-in-class" ActRIIA type activin receptor fusion protein. It fuses the extracellular domain of modified ActRIIA with the Fc end of an antibody. It can block the binding of activin to receptors on the cell membrane, thereby reducing activin-mediated signaling. In preclinical studies, it can reverse remodeling of the pulmonary arterial walls and the right ventricle. Winrevair is a key therapy obtained by Merck in 2021 through the acquisition of Acceleron Pharma for approximately $11.5 billion. It was approved for marketing by the US FDA in March of this year.