Study of Sotatercept in Newly Diagnosed Intermediate- and High-Risk PAH Participants (MK-7962-005/A011-13)

Inclusion Criteria: Inclusion criteria include but are not limited to: * Documented diagnostic right heart catheterization (RHC) within 12 months of screening documenting a minimum pulmonary vascular resistance (PVR) of ≥ 4 Wood units and pulmonary capillary wedge pressure (PCWP) or left ventricular end-diastolic pressure (LVEDP) of ≤ 15 mmHg, with the diagnosis of WHO 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 * Symptomatic PAH classified as World Health Organization (WHO) Functional Class (FC) II or III * Either Registry to Evaluate Early and Long-term PAH Disease Management (REVEAL) Lite 2 Risk Score ≥ 6 or Comparative, Prospective Registry of Newly Initiated Therapies for Pulmonary Hypertension (COMPERA) 2.0 risk score ≥2 (intermediate to-low-risk or above) * Diagnosis of PAH within 12 months of screening and on stable doses of a double or triple combination of background PAH therapies and diuretics (if any) for at least 90 days prior to screening * Six-minute walk distance ≥ 150 m repeated twice at screening at least 4 hours apart, but no longer than 1 week apart, and both values are within 15% of each other (calculated from the highest value) * Females of childbearing potential must meet the following criteria: * Have 2 negative urine or serum pr…