A Long-term Follow-up Study of Sotatercept for PAH Treatment (MK-7962-004/A011-12)

This study is being conducted to assess the long-term safety, tolerability, and efficacy of sotatercept (MK-7962, formerly called ACE-011) in participants with Pulmonary Arterial Hypertension (PAH). This open-label, long-term follow-up (LTFU) study is supported by data from the PULSAR study (Phase 2, NCT03496207) in which treatment with sotatercept resulted in hemodynamic and functional improvements in the study participants, including those receiving maximal PAH therapy with double/triple drug combinations and intravenous prostacyclin.

The primary objective of this open-label, LTFU study is to evaluate the long-term safety and tolerability of sotatercept when added to background PAH therapy in adult participants with PAH who have completed prior sotatercept studies. The secondary objective is to evaluate continued efficacy in adult participants with PAH who have completed prior sotatercept studies.

Participants eligible to enroll in the study will have participated in and completed the relevant study requirements of the parent PAH sotatercept clinical studies.

Eligibility Criteria:
Inclusion Criteria:

* Have completed their current respective PAH sotatercept clinical study and its requirements, and must not have discontinued early
* Must be willing to adhere to the study visit schedule and understand and comply with all protocol requirements
* Must have the ability to understand and provide documented informed consent
* Females of childbearing potential must:

  * Have a negative pregnancy test as verified by the investigator prior to starting study drug administration; she must agree to ongoing pregnancy testing during the course of the study and until 8 weeks after the last dose of the study drug
  * If sexually active, have used, and agree to continue to use highly effective contraception in combination with a barrier method without interruption, for at least 28 days prior to starting the investigational product, during the study (including dose interruptions), and for 16 weeks (112 days) after discontinuation of study drug
  * Refrain from breastfeeding a child or donating blood, eggs, or ovum for the duration of the study and for at least 16 weeks (112 days) after the last dose of study drug
* Male participants must:

  * Agree to use a condom, defined as a male latex condom or non latex condom NOT made out of natural (animal) membrane (e.g., polyurethane), during sexual contact with a pregnant female or a female of childbearing potential while participating in the study, during dose interruptions, and for at least 16 weeks (112 days) following investigational product discontinuation, even if he has undergone a successful vasectomy
  * Refrain from donating blood or sperm for the duration of the study and for 16 weeks (112 days) after the last dose of study drug
* Must agree not to participate in any other trials of investigational drugs/devices while they are enrolled in the MK-7962-004 study

Exclusion Criteria:

* Did not participate in a sotatercept PAH parent trial
* 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 (SAE) that occurred during a PAH sotatercept clinical study that is assessed to be possibly or probably related to sotatercept
* Pregnant or breastfeeding females