05:45 AM EDT, 09/30/2025 (MT Newswires) -- Merck ( MRK ) said Tuesday its phase 3 trial showed its experimental drug, Winrevair, significantly reduced the risk of clinical worsening events by 76% in adults with pulmonary arterial hypertension at intermediate or high risk, compared to placebo.

The company said the benefit was observed within six weeks and sustained over time.

Only 10.6% of patients on Winrevair experienced a worsening event versus 36.9% on placebo, it added.

The drugmaker said the treatment was effective across all key subgroups and had a safety profile consistent with earlier studies.

Merck ( MRK ) said Winrevair also achieved statistically significant improvements in two key secondary measures, including multicomponent clinical improvement and maintenance or achievement of a low disease risk score.