Overview

The purpose of this study is to demonstrate superiority of macitentan 75 milligrams (mg) in prolonging the time to the first clinical events committee (CEC)-adjudicated morbidity or mortality (M/M) event in participants with symptomatic pulmonary arterial hypertension (PAH) compared to macitentan 10 mg.

Eligibility

Inclusion Criteria:

• Target population: greater than or equal to (>=) 18 (or the legal age of consent in the jurisdiction in which the study is taking place) years of age
• Target population: Symptomatic Pulmonary Arterial Hypertension (PAH) in World Health Organization Functional Class (WHO FC) II, III, or IV
• Target population: PAH subtype falling in one of the below classifications: Idiopathic; Heritable; Drug- or toxin-induced; Related to: Connective tissue disease, HIV infection, Portal hypertension, and Congenital heart disease with simple systemic-to-pulmonary shunt (atrial septal defect, ventricular septal defect, patent ductus arteriosus) with persistent PH documented by an Right heart catheterization (RHC) >= 1 year after surgical repair
• PAH diagnosis confirmed by hemodynamic evaluation at rest at any time prior to screening: Mean pulmonary artery pressure (mPAP) > 20 millimeters of mercury (mmHg), and; Pulmonary artery wedge pressure (PAWP) or left ventricular end diastolic pressure (LVEDP) less than or equal to (<=) 15 mmHg, and PVR >= 3 Wood Units (that is, >= 240 dyn*sec/cm^5)
• Able to perform the 6-minute walking test (6MWT) with a minimum distance of 50 meters and maximum distance of 440 meters at screening

Exclusion Criteria:

• Known presence of three or more of the following risk factors for heart failure with preserved ejection fraction at screening, based on records that confirm documented medical history: Body mass index (BMI) > 30 kilograms per meter square (kg/m^2), Diabetes mellitus of any type, Essential hypertension (even if well controlled); Coronary artery disease, that is, any of the following: history of stable angina, or known more than 50 percent (%) stenosis in a coronary artery, or history of myocardial infarction, or history of or planned coronary artery bypass grafting and/or coronary artery stenting
• Known presence of moderate or severe obstructive lung disease (forced expiratory volume in 1 second [FEV1] / forced vital capacity [FVC] < 70%; and FEV1 < 60% of predicted after bronchodilator administration) at any time prior to screening
• Known moderate to severe hepatic impairment, defined as Child-Pugh Class B or C, based on records that confirm documented medical history
• Serum aspartate aminotransferase (AST) and/or alanine aminotransferase (ALT) > 1.5*upper limit of normal (ULN) at screening
• Hemoglobin < 100 gram per liter (g/L) (< 10 gram per deciliter [g/dL]) at screening