A Clinical Study to Investigate the Long-term Safety of the Drug Macitentan in Patients With Pulmonary Hypertension Who Were Previously Treated With Macitentan in Clinical Studies.

Prior treatment

• Planned or current treatment with another investigational treatment up to 3 months prior to Enrollment
• Treatment with a strong CYP3A4 inhibitor (e.g., ketoconazole, itraconazole, voriconazole, clarithromycin, telithromycin, nefazodone, ritonavir, and saquinavir)

Other illness

• Known and documented history of severe hepatic impairment that is Child-Pugh Class C.
• Known hypersensitivity to macitentan, its excipients, or drugs of the same class
• Any known factor or disease that may interfere with treatment compliance, study conduct, or interpretation of the results, such as drug or alcohol dependence or psychiatric disease

Lab values

• Hemoglobin less than 80 gram per liter (g/L)
• Serum Aspartate aminotransferase (AST) and/or alanine aminotransferases (ALT) more than three times the upper limit of normal range

Other

• Pregnant, planning to become pregnant, or breastfeeding

• Signed informed consent to take part in the study before any study mandated procedure.
• Participants from one of the parent studies and: a) the sponsor has decided to terminate the parent study in that country and b) the participant has completed the end of treatment (EOT) Visit of the parent study
• Women of childbearing potential are able to take part in the study if the following applies: a) Urine pregnancy test is negative at Enrollment; b) Agreement to perform monthly urine or serum pregnancy tests during the study and up to at least 30 days after the study treatment discontinuation; and c) Agreement to adhere to the planned contraception scheme from Enrollment up to at least 30 days after study treatment discontinuation