A Clinical Study of Sotatercept (MK-7962) in People With Pulmonary Arterial Hypertension (MK-7962-038)

Inclusion Criteria: The main inclusion criteria include but are not limited to the following: * Has completed their current respective PAH sotatercept clinical study and its requirements, and must not have discontinued early * Is willing to adhere to the study visit schedule, and understands and will comply with all protocol requirements * Must have the ability to understand and provide documented informed consent Exclusion Criteria: The main exclusion criteria include but are not limited to the following: * Did not participate in a sotatercept PAH parent study * Missed more than the equivalent of 4 consecutive doses between the end of parent study and the start of this study. * Presence of an ongoing serious adverse event that occurred during a PAH sotatercept clinical study that is assessed to be possibly or probably related to sotatercept * Is a female who is pregnant or breastfeeding * Is or has an immediate family member who is investigational site or Sponsor staff directly involved with this study * Is currently enrolled in another investigational product study other than a sotatercept study * Is incapacitated