Merck & Co – known as MSD outside of the US and Canada – has shared positive top-line results from a late-stage trial of its pulmonary arterial hypertension (PAH) therapy Winrevair (sotatercept-csrk).
The phase 3 ZENITH study has been evaluating the drug against placebo, both on top of background PAH therapy, in adults with World Health Organization (WHO) functional classes three or four at high risk of mortality.
The study met its primary endpoint, with Winrevair demonstrating a statistically significant and clinically meaningful reduction in the risk of morbidity or mortality events compared to placebo.
Adverse events and serious adverse events were also found in the preliminary assessment to be balanced between the treatment groups.
An independent data monitoring committee has now recommended that the trial be stopped early and all patients be offered the opportunity to receive Winrevair in an open-label extension study.
Affecting approximately 40,000 people in the US, PAH is a progressive disorder in which the blood vessels in the lungs thicken and narrow. This blocks the blood flow through the lungs, which raises blood pressure and results in a significant strain on the heart.
The disease progresses rapidly for many patients and leads to limited physical activity, heart failure and reduced life expectancy.
Administered as an injection, Merck’s Winrevair is designed to improve the balance between pro-proliferative and anti-proliferative signalling to modulate vascular proliferation.
The activin signalling inhibitor was approved by the European Commission in August for use in combination with other PAH therapies to improve exercise capacity in adults with WHO functional classes two to three, and is already approved in the US and other countries for PAH.
Commenting on the latest results for the therapy, Eliav Barr, senior vice president and head of global clinical development, chief medical officer, Merck Research Laboratories, said: “PAH is a serious, progressive disease with a high incidence of morbidity and mortality… These findings are impressive, set a high evidentiary bar for studies of future candidates developed for the treatment of PAH and support the potential of Winrevair to be practice-changing in the management of PAH.”