Change from baseline to Week 24 in hemodynamic variable: mPAP was reported. mPAP is calculated as: 2*diastolic pulmonary arterial pressure (dPAP) + systolic pulmonary arterial pressure (sPAP)/3.

Change from baseline to Week 24 in hemodynamic variable: CI was reported. CI was calculated as: CO/Body surface area (BSA).

Change from baseline to Week 24 in hemodynamic variable: CO was reported.

Change from baseline to Week 24 in hemodynamic variable: TPR was reported. TPR was calculated as: (mPAP/CO)*80.

Percent change from baseline to Week 24 in hemodynamic variable: SvO(2) was reported.

WHO-FC for participants with pulmonary arterial hypertension (PAH) ranges: Class I (no limitation in physical activity, ordinary physical activity did not cause undue dyspnea or fatigue, chest pain or near syncope), Class II (slight limitation of physical activity, comfortable at rest, ordinary physical activity caused undue dyspnea or fatigue, chest pain, or near syncope), Class III (marked limitation of physical activity, comfortable at rest, less than ordinary activity causes undue dyspnea or fatigue, chest pain, or near syncope) and Class IV (cannot perform a physical activity without any symptoms, signs of right heart failure, dyspnea and/or fatigue may be present even at rest, discomfort is increased by any physical activity). Participants who improve in WHO FC are reported below. Improvement was defined as reduction in FC.

Panama FC for PAH ranges: Class I (asymptomatic, growing normally, attending nursery/school regularly, no limitation of physical activity, playing sports with his/her classmates), Class II (slight limitation of physical activity, unduly dyspnoeic and fatigued when playing with his/her classmates, comfortable at rest, grow along own centiles, nursery/school attendance 75% normal, no chest pain), Class IIIa (marked limitation of physical activity, no attempt at sports, comfortable at rest, less than ordinary activity (example: dressing) causes undue dyspnea, fatigue, syncope and/or presyncope or chest pain, nursery/schooling compromised <50% normal attendance), Class IIIb (growth compromised, poor appetite, supplemental feeding, same as class IIIa) and Class IV (cannot perform a physical activity without any symptoms, dyspnea at rest). Participants who improve in Panama FC are reported below. Improvement was defined as reduction in Panama FC.

Change from baseline to Weeks 24 and 52 in 6MWD as measured by 6MWT was reported. 6MWD was the distance that a participant could walk in 6 minutes. Rest periods were allowed if the participant could no longer continue. If the participant need to rest, he/she may pause, lean against the wall and continue walking whenever he/she feels able. The timer continued to run even if the participant stopped to rest.

Change from baseline to Weeks 12, 24, 28, 40, and 52 in NT-proBNP was reported.

Change from baseline to Weeks 12, 24, and 52 in TAPSE was reported. It was calculated as: original TAPSE value/body surface area (BSA). TAPSE was a dimension used to evaluate Right Ventricle (RV) longitudinal systolic function; it measured the extent of systolic motion of the lateral portion of the tricuspid ring towards the apex.

Change from baseline to Weeks 12, 24, and 52 in LVEI was reported. It included diastolic (D) LVEI and systolic (S) LVEI. Left ventricular (LV) internal diameters were measured using the parasternal short axis view at the level of the papillary muscles: D1: LV internal diameter perpendicular to interventricular septum at end-diastole; D2: LV internal diameter parallel to interventricular septum, and at right angle from D1, at end-diastole; S1: LV internal diameter perpendicular to interventricular septum at end-systole; S2: LV internal diameter parallel to interventricular septum, and at a right angle from S1, at end-systole. The LVEI was a ratio that was calculated by sponsor as: LVEI diastole = D2/D1; LVEI systole = S2/S1.

Change from baseline to Weeks 12, 24, and 52 in QoL as assessed by PedsQL 4.0 generic core scales SF-15 was reported. The PedsQL 4.0 questionnaire generic core scales score SF-15 assessed general physical, emotional, social and school functioning on a 5-point Likert scale from 0 to 4 with 0= if it is never a problem, 1= if it is almost never a problem, 2= if it is sometime a problem, 3= if it is often a problem, 4 if it is almost always a problem. Scores were transformed on a scale from 0 to 100. Higher scores indicated better health related QoL. The QoL questionnaire was completed by parent(s)/caregiver(s) and by participants.

Change from baseline to Weeks 12, 24, and 52 in physical activity as measured by accelerometry: number of hours of daytime activity was reported.

Change from baseline to Weeks 12, 24, and 52 in physical activity as measured by accelerometry: mean count per minute of daily activity was reported.

Change from baseline to Weeks 12, 24, and 52 in physical activity as measured by accelerometry: mean daily time spent in light physical activity was reported.

Change from baseline to Weeks 12, 24, and 52 in physical activity as measured by accelerometry: mean daily time spent in moderate to vigorous physical activity was reported.

Change from baseline to Weeks 24 and 52 in BDI was reported. BDI was a 10-point scale rating the maximum level of dyspnea experienced during the 6MWT. Scores ranged from 0 (no shortness of breath) to 10 (worst shortness of breath you have ever had). Higher score indicated worse outcome.

Number of participants with TEAEs was reported. An adverse event (AE) was any untoward medical occurrence in a clinical study participant administered a medicinal (investigational or non-investigational) product. An AE does not necessarily have a causal relationship with the intervention. TEAEs are defined as any AE occurring at or after the initial administration of study intervention through the day of last dose plus 30 days.

Number of participants with TESAEs was reported. An AE is any untoward medical occurrence in a clinical study participant administered a medicinal (investigational or non-investigational) product. An AE does not necessarily have a causal relationship with the intervention. A SAE is an AE resulting in any of the following outcomes or deemed significant for any other reason: death; initial or prolonged inpatient hospitalization; life-threatening experience (immediate risk of dying); persistent or significant disability/incapacity; congenital anomaly. TESAEs are defined as any SAE occurring at or after the initial administration of study intervention through the day of last dose plus 30 days.

Number of participants with AEs leading to premature discontinuation of study drug was reported. An AE is any untoward medical occurrence in a clinical study participant administered a medicinal (investigational or non-investigational) product. An AE does not necessarily have a causal relationship with the intervention.

Number of participants with TEAEs of special interest was reported. It included anemia/decreased hemoglobin level, oedema/fluid retention, hepatic impairment and hypotension. TEAEs are defined as any AE occurring at or after the initial administration of study intervention through the day of last dose plus 30 days.

Number of participants with postbaseline markedly abnormal hematology laboratory values was reported. It included Hematocrit:<0.28% of blood cells (<0.32M[%]), Hemoglobin: < 100 grams per liter (g/L), Leukocytes: <3.0 10^9 cells per Liter (L), and Leukocytes: <3.0 10^9 cells/L. Abnormality was judged at the discretion of investigator. Data is reported for categories where at least one participant had abnormality.

Number of participants with postbaseline markedly abnormal clinical chemistry laboratory values was reported. It included Potassium: >6.0 millimoles per liter (mmol/L) and Calcium: <1.75 mmol/L. Abnormality was judged at the discretion of investigator. Data is reported for categories where at least one participant had abnormality.

Number of participants with postbaseline markedly abnormal clinical chemistry laboratory values (ALP) was reported. It included Alkaline Phosphatase (ALP): > 2.5 * Upper Limit of Normal (ULN). Abnormality was judged at the discretion of investigator. Participants were assessed at Weeks 4, 8, 12, 16, 20, 24, 28, 40, 52. Data is reported for categories where at least one participant had abnormality at any time point: Weeks 20, 40, and 52 reported.

Change from baseline in hematology parameters: platelets, leukocytes, lymphocytes, monocytes, eosinophils, and basophils was reported. Data for each parameters was planned to be reported at specified timepoints only.

Change from baseline in hematology parameter: hematocrit was reported.

Change from baseline in hematology parameter: hemoglobin was reported.

Change from baseline in hematology parameter: erythrocytes was reported.

Change from baseline in chemistry parameters: sodium, potassium, urea nitrogen, glucose, and calcium was reported.

Change from baseline in chemistry parameters: Creatinine, bilirubin, and direct bilirubin was reported.

Change from baseline in chemistry parameter: creatinine clearance was reported.

Change from baseline in chemistry parameter: GFR from Cystatin C Adjusted for BSA was reported.

Change from baseline in chemistry parameters: AST, ALT, and ALP was reported.

Change from baseline in vital signs: blood pressure was reported. It included systolic blood pressure (SBP) and diastolic blood pressure (DBP).

Change from baseline in vital signs: pulse rate was reported.

Change from baseline in ECG: heart rate was reported.

Change from baseline in ECG: PR, QRS, QT, QTcB, and QTcF intervals was reported.

Plasma concentration of macitentan was reported.

Plasma concentration of aprocitentan was reported.

Plasma concentration of macitentan was reported.

Plasma concentration of aprocitentan was reported.

Change from baseline to Week 24 in hemodynamic variable: PVR was reported. PVR is calculated as: PVR= (Mean pulmonary artery pressure [mPAP]-Pulmonary artery wedge pressure [PAWP)/ Cardiac output [CO].](streamdown:incomplete-link)

Efficacy analysis set included all participants who took at least 1 dose of study intervention.

Change from baseline to Week 24 in hemodynamic variable: mRAP was reported.

Efficacy analysis set included all participants who took at least 1 dose of study intervention.

Change from baseline to Week 24 in hemodynamic variable: mPAP was reported. mPAP is calculated as: 2*diastolic pulmonary arterial pressure (dPAP) + systolic pulmonary arterial pressure (sPAP)/3.

Efficacy analysis set included all participants who took at least 1 dose of study intervention.

Change from baseline to Week 24 in hemodynamic variable: CI was reported. CI was calculated as: CO/Body surface area (BSA).

Efficacy analysis set included all participants who took at least 1 dose of study intervention.

Change from baseline to Week 24 in hemodynamic variable: CO was reported.

Efficacy analysis set included all participants who took at least 1 dose of study intervention.

Change from baseline to Week 24 in hemodynamic variable: TPR was reported. TPR was calculated as: (mPAP/CO)*80.

Efficacy analysis set included all participants who took at least 1 dose of study intervention.

Percent change from baseline to Week 24 in hemodynamic variable: SvO(2) was reported.

Efficacy analysis set included all participants who took at least 1 dose of study intervention.

WHO-FC for participants with pulmonary arterial hypertension (PAH) ranges: Class I (no limitation in physical activity, ordinary physical activity did not cause undue dyspnea or fatigue, chest pain or near syncope), Class II (slight limitation of physical activity, comfortable at rest, ordinary physical activity caused undue dyspnea or fatigue, chest pain, or near syncope), Class III (marked limitation of physical activity, comfortable at rest, less than ordinary activity causes undue dyspnea or fatigue, chest pain, or near syncope) and Class IV (cannot perform a physical activity without any symptoms, signs of right heart failure, dyspnea and/or fatigue may be present even at rest, discomfort is increased by any physical activity). Participants who improve in WHO FC are reported below. Improvement was defined as reduction in FC.

Analysis population included all participants greater than (>) 4 years of age.

Panama FC for PAH ranges: Class I (asymptomatic, growing normally, attending nursery/school regularly, no limitation of physical activity, playing sports with his/her classmates), Class II (slight limitation of physical activity, unduly dyspnoeic and fatigued when playing with his/her classmates, comfortable at rest, grow along own centiles, nursery/school attendance 75% normal, no chest pain), Class IIIa (marked limitation of physical activity, no attempt at sports, comfortable at rest, less than ordinary activity (example: dressing) causes undue dyspnea, fatigue, syncope and/or presyncope or chest pain, nursery/schooling compromised <50% normal attendance), Class IIIb (growth compromised, poor appetite, supplemental feeding, same as class IIIa) and Class IV (cannot perform a physical activity without any symptoms, dyspnea at rest). Participants who improve in Panama FC are reported below. Improvement was defined as reduction in Panama FC.

Efficacy analysis set included all participants who took at least 1 dose of study intervention.

Change from baseline to Weeks 24 and 52 in 6MWD as measured by 6MWT was reported. 6MWD was the distance that a participant could walk in 6 minutes. Rest periods were allowed if the participant could no longer continue. If the participant need to rest, he/she may pause, lean against the wall and continue walking whenever he/she feels able. The timer continued to run even if the participant stopped to rest.

Analysis population included all participants greater than equal to (>=) 6 years of age. Here, "n" (number analyzed) refer to the number of participants evaluable at specified timepoints.

Change from baseline to Weeks 12, 24, 28, 40, and 52 in NT-proBNP was reported.

Efficacy analysis set included all participants who took at least 1 dose of study intervention. Here, "n" (number analyzed) refer to the number of participants evaluable at specified timepoints.

Change from baseline to Weeks 12, 24, and 52 in TAPSE was reported. It was calculated as: original TAPSE value/body surface area (BSA). TAPSE was a dimension used to evaluate Right Ventricle (RV) longitudinal systolic function; it measured the extent of systolic motion of the lateral portion of the tricuspid ring towards the apex.

Efficacy analysis set included all participants who took at least 1 dose of study intervention. Here, "n" (number analyzed) refer to the number of participants evaluable at specified timepoints.

Change from baseline to Weeks 12, 24, and 52 in LVEI was reported. It included diastolic (D) LVEI and systolic (S) LVEI. Left ventricular (LV) internal diameters were measured using the parasternal short axis view at the level of the papillary muscles: D1: LV internal diameter perpendicular to interventricular septum at end-diastole; D2: LV internal diameter parallel to interventricular septum, and at right angle from D1, at end-diastole; S1: LV internal diameter perpendicular to interventricular septum at end-systole; S2: LV internal diameter parallel to interventricular septum, and at a right angle from S1, at end-systole. The LVEI was a ratio that was calculated by sponsor as: LVEI diastole = D2/D1; LVEI systole = S2/S1.

Efficacy analysis set included all participants who took at least 1 dose of study intervention.

Change from baseline to Weeks 12, 24, and 52 in QoL as assessed by PedsQL 4.0 generic core scales SF-15 was reported. The PedsQL 4.0 questionnaire generic core scales score SF-15 assessed general physical, emotional, social and school functioning on a 5-point Likert scale from 0 to 4 with 0= if it is never a problem, 1= if it is almost never a problem, 2= if it is sometime a problem, 3= if it is often a problem, 4 if it is almost always a problem. Scores were transformed on a scale from 0 to 100. Higher scores indicated better health related QoL. The QoL questionnaire was completed by parent(s)/caregiver(s) and by participants.

Analysis population included all participants >=2 years of age. Here, "n" (number analyzed) refer to the number of participants evaluable at specified timepoints.

Change from baseline to Weeks 12, 24, and 52 in physical activity as measured by accelerometry: number of hours of daytime activity was reported.

Analysis population included all participants >=2 years of age.

Change from baseline to Weeks 12, 24, and 52 in physical activity as measured by accelerometry: mean count per minute of daily activity was reported.

Analysis population included all participants >=2 years of age.

Change from baseline to Weeks 12, 24, and 52 in physical activity as measured by accelerometry: mean daily time spent in light physical activity was reported.

Analysis population included all participants >=2 years of age.

Change from baseline to Weeks 12, 24, and 52 in physical activity as measured by accelerometry: mean daily time spent in moderate to vigorous physical activity was reported.

Analysis population included all participants >=2 years of age.

Change from baseline to Weeks 24 and 52 in BDI was reported. BDI was a 10-point scale rating the maximum level of dyspnea experienced during the 6MWT. Scores ranged from 0 (no shortness of breath) to 10 (worst shortness of breath you have ever had). Higher score indicated worse outcome.

Analysis population included all participants greater than equal to (>=) 6 years of age.

Number of participants with TEAEs was reported. An adverse event (AE) was any untoward medical occurrence in a clinical study participant administered a medicinal (investigational or non-investigational) product. An AE does not necessarily have a causal relationship with the intervention. TEAEs are defined as any AE occurring at or after the initial administration of study intervention through the day of last dose plus 30 days.

Safety analysis set included all participants who took at least 1 dose of study intervention.

Number of participants with TESAEs was reported. An AE is any untoward medical occurrence in a clinical study participant administered a medicinal (investigational or non-investigational) product. An AE does not necessarily have a causal relationship with the intervention. A SAE is an AE resulting in any of the following outcomes or deemed significant for any other reason: death; initial or prolonged inpatient hospitalization; life-threatening experience (immediate risk of dying); persistent or significant disability/incapacity; congenital anomaly. TESAEs are defined as any SAE occurring at or after the initial administration of study intervention through the day of last dose plus 30 days.

Safety analysis set included all participants who took at least 1 dose of study intervention.

Number of participants with AEs leading to premature discontinuation of study drug was reported. An AE is any untoward medical occurrence in a clinical study participant administered a medicinal (investigational or non-investigational) product. An AE does not necessarily have a causal relationship with the intervention.

Safety analysis set included all participants who took at least 1 dose of study intervention

Number of participants with TEAEs of special interest was reported. It included anemia/decreased hemoglobin level, oedema/fluid retention, hepatic impairment and hypotension. TEAEs are defined as any AE occurring at or after the initial administration of study intervention through the day of last dose plus 30 days.

Safety analysis set included all participants who took at least 1 dose of study intervention.

Number of participants with postbaseline markedly abnormal hematology laboratory values was reported. It included Hematocrit:<0.28% of blood cells (<0.32M[%]), Hemoglobin: < 100 grams per liter (g/L), Leukocytes: <3.0 10^9 cells per Liter (L), and Leukocytes: <3.0 10^9 cells/L. Abnormality was judged at the discretion of investigator. Data is reported for categories where at least one participant had abnormality.

Safety analysis set included all participants who took at least 1 dose of study intervention.

Number of participants with postbaseline markedly abnormal clinical chemistry laboratory values was reported. It included Potassium: >6.0 millimoles per liter (mmol/L) and Calcium: <1.75 mmol/L. Abnormality was judged at the discretion of investigator. Data is reported for categories where at least one participant had abnormality.

Safety analysis set included all participants who took at least 1 dose of study intervention.

Number of participants with postbaseline markedly abnormal clinical chemistry laboratory values (ALP) was reported. It included Alkaline Phosphatase (ALP): > 2.5 * Upper Limit of Normal (ULN). Abnormality was judged at the discretion of investigator. Participants were assessed at Weeks 4, 8, 12, 16, 20, 24, 28, 40, 52. Data is reported for categories where at least one participant had abnormality at any time point: Weeks 20, 40, and 52 reported.

Safety analysis set included all participants who took at least 1 dose of study intervention. Here, "N" (overall number of participants analyzed) refers to the number of participants evaluable for this outcome measure.

Change from baseline in hematology parameters: platelets, leukocytes, lymphocytes, monocytes, eosinophils, and basophils was reported. Data for each parameters was planned to be reported at specified timepoints only.

Safety analysis set included all participants who took at least 1 dose of study intervention. Here, "n" (number analyzed) refer to the number of participants evaluable at specified timepoints.

Change from baseline in hematology parameters: NBF was reported. Data for each parameters was planned to be reported at specified timepoints only.

Safety analysis set included all participants who took at least 1 dose of study intervention. Here, "n" (number analyzed) refer to the number of participants evaluable at specified timepoints.

Change from baseline in hematology parameter: hematocrit was reported.

Safety analysis set included all participants who took at least 1 dose of study intervention. Here, "n" (number analyzed) refer to the number of participants evaluable at specified timepoints.

Change from baseline in hematology parameter: hemoglobin was reported.

Safety analysis set included all participants who took at least 1 dose of study intervention. Here, "n" (number analyzed) refer to the number of participants evaluable at specified timepoints.

Change from baseline in hematology parameter: erythrocytes was reported.

Safety analysis set included all participants who took at least 1 dose of study intervention. Here, "n" (number analyzed) refer to the number of participants evaluable at specified timepoints.

Change from baseline in chemistry parameters: sodium, potassium, urea nitrogen, glucose, and calcium was reported.

Safety analysis set included all participants who took at least 1 dose of study intervention. Here, "n" (number analyzed) refer to the number of participants evaluable at specified timepoints.

Change from baseline in chemistry parameters: Creatinine, bilirubin, and direct bilirubin was reported.

Safety analysis set included all participants who took at least 1 dose of study intervention. Here, "n" (number analyzed) refer to the number of participants evaluable at specified timepoints

Change from baseline in chemistry parameter: creatinine clearance was reported.

Safety analysis set included all participants who took at least 1 dose of study intervention. Here, "n" (number analyzed) refer to the number of participants evaluable at specified timepoints

Change from baseline in chemistry parameter: GFR from Cystatin C Adjusted for BSA was reported.

Safety analysis set included all participants who took at least 1 dose of study intervention. Here, "n" (number analyzed) refer to the number of participants evaluable at specified timepoints

Change from baseline in chemistry parameters: AST, ALT, and ALP was reported.

Safety analysis set included all participants who took at least 1 dose of study intervention. Here, "n" (number analyzed) refer to the number of participants evaluable at specified timepoints

Change from baseline in vital signs: blood pressure was reported. It included systolic blood pressure (SBP) and diastolic blood pressure (DBP).

Safety analysis set included all participants who took at least 1 dose of study intervention. Here, "n" (number analyzed) refer to the number of participants evaluable at specified timepoints

Change from baseline in vital signs: pulse rate was reported.

Safety analysis set included all participants who took at least 1 dose of study intervention. Here, "n" (number analyzed) refer to the number of participants evaluable at specified timepoints

Change from baseline in ECG: heart rate was reported.

Safety analysis set included all participants who took at least 1 dose of study intervention.

Change from baseline in ECG: PR, QRS, QT, QTcB, and QTcF intervals was reported.

Safety analysis set included all participants who took at least 1 dose of study intervention.

Plasma concentration of macitentan was reported.

Analysis population included all participants >=2 years of age. Here, "n" (number analyzed) refer to the number of participants evaluable at specified timepoints.

Plasma concentration of aprocitentan was reported.

Analysis population included all participants >=2 years of age. Here, "n" (number analyzed refer to the number of participants evaluable at specified timepoints.

Plasma concentration of macitentan was reported.

Analysis population included all participants <2 years of age. Since number of participants analyzed were <3, hence data was not summarized. Only participant wise data was reported.

Plasma concentration of aprocitentan was reported.

Analysis population included all participants <2 years of age. Since number of participants analyzed were <3, hence data was not summarized. Only participant wise data was reported.