A Study of Sotatercept for the Treatment of Pulmonary Arterial Hypertension

This is a Phase 2a, single-arm, open-label, multicenter exploratory study to determine the effects of sotatercept plus SOC in adults with WHO functional class III PAH. All eligible participants will receive SOC plus sotatercept at a starting dose level of 0.3 mg/kg by subcutaneous (SC) injection for Cycle 1 and escalating to 0.7 mg/kg at Cycle 2 for the remainder of the treatment period. Participants will be required to attend clinic visits once every three weeks for the 24-week treatment period and once every three weeks for the 18-month extension period to perform one or more protocol specified evaluations. Evaluations include hemodynamic measures collected during right heart catheterization (RHC) with invasive cardiopulmonary exercise test (iCPET), and cardiac magnetic resonance imaging (MR), 6-minute walk distance (6MWD), pharmacokinetic parameters, pharmacodynamic parameters, anti-drug antibody testing, and adverse events.