A Clinical Study of Sotatercept (MK-7962) in People With Pulmonary Arterial Hypertension (PAH) (MK-7962-024)

Inclusion Criteria: * Has documented diagnostic Right Heart Catheterization, with the diagnosis of World Health Organization (WHO) Pulmonary Atrial Hypertension (PAH) Group 1 in any of the following subtypes: Idiopathic PAH, Heritable PAH, Drug/toxin-induced PAH, PAH associated with connective tissue disease, PAH associated with simple, congenital systemic-to-pulmonary shunts at least 1 year following repair * Has symptomatic PAH classified as WHO Functional Class II or III Exclusion Criteria: * Has a weight of \<35 kg * Has a diagnosis of PH WHO Groups 2, 3, 4, or 5 * Has a diagnosis of the following PAH Group 1 subtypes: HIV-associated PAH, PAH associated with portal hypertension, Exclusion in PAH Group 1 should also include schistosomiasis-associated PAH, pulmonary veno occlusive disease and pulmonary capillary hemangiomatosis * Has uncontrolled systemic hypertension * Has a history of pneumonectomy * Has a history of known pericardial constriction * Has a history of restrictive cardiomyopathy * Has history of atrial septostomy (within 180 days prior to study start) * Has personal or family history of long QT syndrome * Has history of coronary artery disease (myocardial infarction, percutaneous coronary intervention, coronary artery bypass, graft surgery, or cardiac anginal chest pain) (within 6 months prior to study start) * Has a cerebrovascular accident (within 3 months prior to study start) * Has significant (\>2+ regurgitation) mitral regurgitation or aortic regurgitation valvular disease * Has untreated more than mild obstructive sleep apnea * Has known malignancy that is progressing or has required active treatment within the past 5 years * Has recently started (within 12 months prior to study start) or has plans to start weight loss medication or enter a weight loss program during the study period * Has a previous (within 3 years) or planned (during the study) obesity treatment with surgery or a weight-loss device