Clinical Trial Finder

Inclusion Criteria:

• - Participant must sign an informed consent form (ICF) (or their legally acceptable representative must sign) indicating that participant understands the purpose of, and procedures required for, the study and is willing to participate in the study.

• - Participant treated with oral macitentan or selexipag or fixed dose combination (FDC) of macitentan 10 milligrams (mg) and tadalafil 40 mg at the end of a sponsor parent study and: a) the indication of the parent study is included in the intervention-specific appendices (ISA) (pulmonary arterial hypertension [PAH] or chronic thromboembolic pulmonary hypertension [CTEPH] for adults, PAH for pediatric participants); b) participant has completed the parent study; c) no alternative means of access to study intervention (or equivalent approved therapy) have been identified; d) participant may continue to benefit from treatment with the study intervention; e) Participant is at least 18 years old for selexipag or macitentan/tadalafil FDC, and at least 2 years old for macitentan.

• - A female participant of childbearing potential must: a) have a negative urine or serum pregnancy test prior to first intake of study intervention; b) agree to perform monthly urine pregnancy test up to the end of the safety follow-up period; c) agree to follow contraceptive methods until 30 days after the last intake of the study intervention.

Exclusion Criteria:

General:

• - Participants prematurely discontinued from the study intervention in their parent study.

• - Female participant being pregnant, or breastfeeding, or planning to become pregnant while enrolled in this study.

• - Planned or current treatment with another investigational treatment.

Macitentan-specific:

• - Known allergies, hypersensitivity, or intolerance to macitentan or its excipients.

• - Hemoglobin less than (<) 80 grams per liter (g/L) - Serum aspartate (AST) and/or alanine aminotransferases (ALT) greater than (>) 3* upper limit of normal (ULN) - Known and documented severe hepatic impairment that is, Child-Pugh Class C.

For participants with hepatic impairment, Child-Pugh Class (Child-Pugh score) should be fully assessed and documented in the source documents at screening. Selexipag-specific:

• - Known allergies, hypersensitivity, or intolerance to selexipag or its excipients.

• - Suspected or known pulmonary veno-occlusive disease (PVOD) - Uncontrolled thyroid disease.

• - Severe coronary heart disease or unstable angina, myocardial infarction within the last 6 months, decompensated cardiac failure (if not under close medical supervision), severe arrhythmia, cerebrovascular events (for example, transient ischemic attack, stroke) within the last 3 months, or congenital or acquired valvular defects with clinically relevant myocardial function disorders not related to pulmonary hypertension (PH) - Known and documented severe hepatic impairment that is, Child-Pugh Class C.

For participants with hepatic impairment, Child-Pugh Class (Child-Pugh score) should be fully assessed and documented in the source documents at screening. Macitentan/tadalafil FDC-specific:

• - Known allergies, hypersensitivity, or intolerance to macitentan or tadalafil or their excipients.

• - Hemoglobin <80 g/L.

• - Serum aspartate (AST) and/or alanine aminotransferases (ALT) >3* ULN range.

• - Known and documented severe hepatic impairment that is, Child-Pugh Class C.

For participants with hepatic impairment, Child-Pugh Class should be fully assessed and documented in the source documents at screening. - Severe renal impairment (estimated glomerular filtration rate [eGF]/creatinine clearance <30 milliliter per minute [mL/min])

Arms

Experimental: Macitentan

Participants who have completed a parent study, benefit from their study intervention maintenance and have no adequate alternative local treatment option will be enrolled in this study and will continue to receive study drug macitentan orally during the course of the study. For adult participants study visits will be scheduled every 6 months and for pediatric participants study visits will be scheduled every 3 months. The study includes on-site visits to collect efficacy and safety information until participant discontinuation/withdrawal, or the respective study intervention is made commercially available in the country/territory or an equivalent approved therapy becomes available, or the sponsor decides to terminate the study prematurely.

Experimental: Selexipag

Participants who have completed a parent study, benefit from their study intervention maintenance and have no adequate alternative local treatment option will be enrolled in this study and will continue to receive study drug selexipag orally during the course of the study. Study visits are scheduled every 6 months to collect efficacy and safety information until participant discontinuation/withdrawal, or the respective study intervention is made commercially available in the country/territory or an equivalent approved therapy becomes available, or the sponsor decides to terminate the study prematurely.

Experimental: Macitentan/Tadalafil FDC

Participants who have completed a parent study, benefit from their study intervention maintenance and have no adequate alternative local treatment option will be enrolled in this study and will continue to receive drug Macitentan and Tadalafil fixed dose combination (FDC) orally during the course of the study. Study visits are scheduled every 6 months to collect efficacy and safety information until participant discontinuation/withdrawal, or the respective study intervention is made commercially available in the country/territory or an equivalent approved therapy becomes available, or the sponsor decides to terminate the study prematurely.

Interventions

Drug: - Macitentan

Adult participants will receive oral dose of macitentan 10 milligrams (mg) tablet once daily. Children greater than or equal to (>=) 2 year to less than (<) 18 years will be given an oral macitentan dose tailored to their body weight, ensuring an equivalent level of systemic exposure as in adults.

Drug: - Selexipag

Participant will receive oral dose of selexipag tablet twice daily at the dose strength corresponding to their maintenance dose at the end of their parent study. Available strengths: 200, 400, 600, 800, 1000, 1200, 1400 and 1600 micrograms.

Drug: - Macitentan/Tadalafil FDC

Participants will receive oral FDC of macitentan 10 mg and tadalafil 40 mg once daily during the course of the study as already received in the parent studies.