Merck, known as MSD outside the U.S. and Canada, announced encouraging results from the Phase 3 HYPERION trial. The study evaluated WINREVAIR™ (sotatercept-csrk) versus placebo, both combined with background therapy, in recently diagnosed adults with pulmonary arterial hypertension (PAH, WHO Group 1) functional class II or III.
Significant Reduction in Clinical Worsening Events
WINREVAIR reduced the risk of clinical worsening events by 76% (HR 0.24; 95% CI, 0.14–0.41; p<0.0001). The composite endpoint included death, non-planned PAH hospitalization, atrial septostomy, lung transplantation, or PAH deterioration. Only 10.6% of patients receiving WINREVAIR experienced at least one event compared with 36.9% in the placebo group. Importantly, treatment benefits appeared within six weeks and remained consistent across subgroups, including those with idiopathic PAH, connective tissue disease, and patients on dual or triple background therapy.
Expert Perspectives
Dr. Vallerie McLaughlin of the University of Michigan noted, “Early diagnosis and treatment are critical. These results show that initiating WINREVAIR within the first year significantly reduces clinical worsening.” Dr. Joerg Koglin of Merck Research Laboratories added, “The totality of data reinforces WINREVAIR’s practice-changing potential.”
Safety Profile and Secondary Endpoints
As per the MERCK Press release, the safety profile matched previous trials. Adverse events occurred in 89.4% of WINREVAIR patients and 90% on placebo, while serious adverse events were slightly lower in the WINREVAIR group. WINREVAIR also achieved statistically significant improvements in multicomponent improvement and maintenance of low REVEAL Lite 2 scores. At week 24, 29.4% of patients met all multicomponent criteria compared with 14.6% on placebo.
Broader Clinical Program
HYPERION, stopped early for positive efficacy, is the third Phase 3 study showing WINREVAIR’s benefits after STELLAR and ZENITH. Currently approved in over 54 countries, WINREVAIR continues to expand its evidence base. Results from HYPERION will now be submitted to global regulatory authorities.