A Study of Sotatercept for the Treatment of Pulmonary Arterial Hypertension (PAH)

This is a Phase 2, double-blind, randomized, placebo-controlled, parallel-group study of sotatercept plus standard of care (SOC) versus placebo plus SOC in participants with PAH of World Health Organization (WHO) Group 1, functional class II-III. Participants will be randomly assigned in a 3:3:4 ratio to receive placebo, sotatercept 0.3 mg/kg, or sotatercept 0.7 mg/kg by subcutaneous (SC) injection every 21 days for a period of 24 weeks in the placebo-controlled treatment period of the study while on SOC therapy. Evaluations will include changes in pulmonary vascular resistance (PVR), 6-minute walk distance (6MWD), quality of life questionnaires, echocardiographic parameters, and safety. Participants who have not discontinued early from the placebo-controlled treatment period and have had their post-treatment period PVR assessment will be able to continue into the 30-month extension period in which sotatercept-treated participants will receive their latest dose level of sotatercept SC every 21 days and placebo-treated participants will be re-randomized 1:1 to receive sotatercept 0.3 mg/kg SC or sotatercept 0.7 mg/kg SC every 21 days while on SOC therapy.