The objective of this study is to evaluate the effects of sotatercept treatment (plus maximum tolerated background pulmonary arterial hypertension (PAH) therapy) versus placebo (plus maximum tolerated background PAH therapy) on time to first event of all cause death, lung transplantation, or PAH worsening-related hospitalization of ≥24 hours, in participants with World Health Organization (WHO) functional class (FC) III or FC IV PAH at high risk of mortality who are FC II or III.
