This is the total number of subjects with at least one adverse event (serious or not serious) whether or not causally related to the study drug and presented cumulatively in the FUTURE 3 and FUTURE 3 Extension study. NOTE: FUTURE 3 extension study was exploratory and no primary efficacy and safety endpoints were defined in the protocol. So, this safety outcome measure was selected and reported as primary endpoint here.

The analysis was performed on the Safety population analysis set, including all patients who received at least one dose of study treatment and evaluated according to the study treatment that they received.

The WHO FC indicates the severity of Pulmonary Arterial Hypertension: class I (none) to class IV (most severe). Changes from baseline to month 12 and month 18 of treatment with bosentan included: improvement (change from a higher to a lower FC), worsening (change from a lower to a higher FC) or no change/stable (same FC at baseline and at the post-baseline time point). Baseline was defined as the last valid assessment performed prior to first study drug intake in the FUTURE 3 core study.

The intent to treat population was used. Where a missing visit score exists between two visits with scores, the missing score was imputed with the worse score of the non-missing scores; if the missing score was not between 2 visits with scores, it was replaced by the last non-missing score.

The WHO FC indicates the severity of Pulmonary Arterial Hypertension: class I (none) to class IV (most severe). Changes from baseline to month 12 and month 18 of treatment with bosentan included: improvement (change from a higher to a lower FC), worsening (change from a lower to a higher FC) or no change/stable (same FC at baseline and at the post-baseline time point). Baseline was defined as the last valid assessment performed prior to first study drug intake in the FUTURE 3 core study.

The intent to treat population was used. Where a missing visit score exists between two visits with scores, the missing score was imputed with the worse score of the non-missing scores; if the missing score was not between 2 visits with scores, it was replaced by the last non-missing score.

The GCIS is a scale used to rate the patient's current overall clinical condition ("Very Good", "Good", "Neither Good or Bad", "Bad", and "Very Bad"). Rating was performed independently by the physician and parents or legal representatives. Baseline was defined as the last valid assessment performed prior to first study drug intake in the FUTURE 3 core study.

The intent to treat population was used for these analyses. No imputation method was used. Only patients with available results at the corresponding time point are included in the analysis.

The GCIS is a scale used to rate the patient's current overall clinical condition ("Very Good", "Good", "Neither Good or Bad", "Bad", and "Very Bad"). Rating was performed independently by the physician and parents or legal representatives. Baseline was defined as the last valid assessment performed prior to first study drug intake in the FUTURE 3 core study.

The intent to treat population was used. No imputation method was used. Only patients with available results at the corresponding time point are including in the analysis.

Number of patients with at least one PAH-worsening component (death, lung transplant, hospitalization due to PAH progression, initiation of new therapy for PAH, new/worsening right heart failure) reported cumulatively over FUTURE 3 core and extension study.

The intent to treat population was used

PAH progression was defined by time elapsed from the first study drug administration in the FUTURE core study to the day of the first occurrence of any of the following PAH worsening events: death, lung transplant, hospitalization due to PAH progression, initiation of new therapy for PAH or new / worsening right heart failure. Subjects without a PAH worsening event were censored at EOT + 7 days. PAH progression was estimated by Kaplan-Meier methodology and expressed by the percentage of participants free of events at different time points.

These are the numbers of patients at risk at the time of study treatment initiation in the FUTURE 3 core study

Overall survival was defined as the time elapsed between the first study drug administration and death (any cause) up to end of study (Month 18 survival follow-up), regardless of whether the patient was on study treatment. Patients who died, regardless of the cause of death, were considered to have had an event. Patients last known to have been alive were censored on their date of last contact. Percentage of participants without death at different time points was estimated using Kaplan-Meier methodology.

These are the numbers of patients at risk at the time of study treatment initiation in the FUTURE 3 core study

An AE is any untoward medical occurrence in a participant participating in a clinical study that does not necessarily have a causal relationship with the pharmaceutical/biological agent under study. TEAEs are defined as AEs with onset during the treatment period or that are a consequence of a pre-existing condition that has worsened since baseline.

Exceptional-use set included all patients who entered the EUTP. Due to change in study conduct, patients treated with bosentan t.i.d. switched to b.i.d. after local Amendment B to global protocol version 2 (17 March 2015 for Belarus and Ukraine, 1 April 2015 for China) and displaying summaries in the EUTP period by dose were not significant. Therefore, the results were reported combined for bosentan b.i.d./t.i.d.

An AE is any untoward medical occurrence in a participant participating in a clinical study that does not necessarily have a causal relationship with the pharmaceutical/biological agent under study. TEAE are defined as AEs with onset during the treatment period or that are a consequence of a pre-existing condition that has worsened since baseline. 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.

Exceptional-use set included all patients who entered the EUTP. Due to change in study conduct, patients treated with bosentan t.i.d. switched to b.i.d. after local Amendment B to global protocol version 2 (17 March 2015 for Belarus and Ukraine, 1 April 2015 for China) and displaying summaries in the EUTP period by dose were not significant. Therefore, the results were reported combined for bosentan b.i.d./t.i.d.

An AE is any untoward medical occurrence in a participant participating in a clinical study that does not necessarily have a causal relationship with the pharmaceutical/biological agent under study. Percentage of participants with AEs leading to premature discontinuation of study drug were reported.

Exceptional-use set included all patients who entered the EUTP. Due to change in study conduct, patients treated with bosentan t.i.d. switched to b.i.d. after local Amendment B to global protocol version 2 (17 March 2015 for Belarus and Ukraine, 1 April 2015 for China) and displaying summaries in the EUTP period by dose were not significant. Therefore, the results were reported combined for bosentan b.i.d./t.i.d.

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.

Exceptional-use set included all patients who entered the EUTP. Due to change in study conduct, patients treated with bosentan t.i.d. switched to b.i.d. after local Amendment B to global protocol version 2 (17 March 2015 for Belarus and Ukraine, 1 April 2015 for China) and displaying summaries in the EUTP period by dose were not significant. Therefore, the results were reported combined for bosentan b.i.d./t.i.d.

Percentage of participants with deaths were reported.

Exceptional-use set included all patients who entered the EUTP. Due to change in study conduct, patients treated with bosentan t.i.d. switched to b.i.d. after local Amendment B to global protocol version 2 (17 March 2015 for Belarus and Ukraine, 1 April 2015 for China) and displaying summaries in the EUTP period by dose were not significant. Therefore, the results were reported combined for bosentan b.i.d./t.i.d.

Percentage of participants with AESI including liver abnormalities and anemia were reported.

Exceptional-use set included all patients who entered the EUTP. Due to change in study conduct, patients treated with bosentan t.i.d. switched to b.i.d. after local Amendment B to global protocol version 2 (17 March 2015 for Belarus and Ukraine, 1 April 2015 for China) and displaying summaries in the EUTP period by dose were not significant. Therefore, the results were reported combined for bosentan b.i.d./t.i.d.

Percentage of participants with treatment-emergent marked laboratory abnormalities were reported.

Exceptional-use set included all patients who entered the EUTP. Due to change in study conduct, patients treated with bosentan t.i.d. switched to b.i.d. after local Amendment B to global protocol version 2 (17 March 2015 for Belarus and Ukraine, 1 April 2015 for China) and displaying summaries in the EUTP period by dose were not significant. Therefore, the results were reported combined for bosentan b.i.d./t.i.d.

Percentage of participants with liver function abnormalities: Alanine aminotransferase (ALT) greater than (>)3*upper limit of normal (ULN), ALT/aspartate aminotransferase (AST) >3*ULN, ALT /AST >3*ULN and less than or equal to (<=) 5*ULN, ALT/AST >5*ULN and <=8*ULN, ALT/AST >8*ULN and ALT/AST >3*ULN, total bilirubin >2*ULN and alkaline phosphatase (ALP) <=2*ULN were reported.

Exceptional-use set included all patients who entered the EUTP. Due to change in study conduct, patients treated with bosentan t.i.d. switched to b.i.d. after local Amendment B to global protocol version 2 (17 March 2015 for Belarus and Ukraine, 1 April 2015 for China) and displaying summaries in the EUTP period by dose were not significant. Therefore, the results were reported combined for bosentan b.i.d./t.i.d.

Percentage of participants with any time occurrence of hemoglobin (Hgb) less than or equal to (<=) 10 g/dL and 8 g/dL between baseline and up to the last day of treatment + 7 days during EUTP were reported. Here "N" (number of subjects analyzed) signifies subjects who were evaluable for this outcome measure.

Exceptional-use set included all patients who entered the EUTP. Due to change in study conduct, patients treated with bosentan t.i.d. switched to b.i.d. after local Amendment B to global protocol version 2 (17 March 2015 for Belarus and Ukraine, 1 April 2015 for China) and displaying summaries in the EUTP period by dose were not significant. Therefore, the results were reported combined for bosentan b.i.d./t.i.d.