Sotatercept in Patients with Pulmonary Arterial Hypertension at High Risk for Death.

Sotatercept improves exercise capacity and delays the time to clinical worsening in patients with World Health Organization (WHO) functional class II or III pulmonary arterial hypertension. The effects of add-on sotatercept in patients with advanced pulmonary arterial hypertension and a high risk of death are unclear. In this phase 3 trial, we randomly assigned patients with pulmonary arterial hypertension (WHO functional class III or IV) and a high 1-year risk of death (Registry to Evaluate Early and Long-Term Pulmonary Arterial Hypertension Disease Management Lite 2 risk score, ≥9) who were receiving the maximum tolerated dose of background therapy to receive add-on sotatercept (starting dose, 0.3 mg per kilogram of body weight; escalated to target dose, 0.7 mg per kilogram) or placebo every 3 weeks. The primary end point was a composite of death from any cause, lung transplantation, or hospitalization (≥24 hours) for worsening pulmonary arterial hypertension, assessed in a time-to-first-event analysis. A total of 172 patients were included (86 each in the sotatercept and placebo groups). The trial was stopped early on the basis of the efficacy results of a prespecified interim analysis. At least one primary end-point event occurred in 15 patients (17.4%) in the sotatercept group and in 47 patients (54.7%) in the placebo group (hazard ratio, 0.24; 95% confidence interval, 0.13 to 0.43; P<0.001). Death from any cause occurred in 7 patients (8.1%) in the sotatercept group and in 13 patients (15.1%) in the placebo group; lung transplantation in 1 patient (1.2%) and 6 patients (7.0%), respectively; and hospitalization for worsening pulmonary arterial hypertension in 8 patients (9.3%) and 43 patients (50.0%). The most common adverse events with sotatercept were epistaxis and telangiectasia. Among high-risk adults with pulmonary arterial hypertension who were receiving the maximum tolerated dose of background therapy, treatment with sotatercept resulted in a lower risk of a composite of death from any cause, lung transplantation, or hospitalization (≥24 hours) for worsening pulmonary arterial hypertension than placebo. (Funded by Merck Sharp and Dohme, a subsidiary of Merck [Rahway, NJ]; ZENITH ClinicalTrials.gov number, NCT04896008.).