The 6MWT was conducted according to the American Thoracic Society guidelines (ATS statement: guidelines for the six-minute walk test. Am J Respir Crit Care Med 2002; 166(1):111-117.) Primary efficacy analyses were performed for the AMB-220-E analysis set (all subjects who received at least 1 dose of study drug during the AMB-220-E study).

The 6MWT was conducted according to the American Thoracic Society guidelines (ATS statement: guidelines for the six-minute walk test. Am J Respir Crit Care Med 2002; 166(1):111-117.) Primary efficacy analyses were performed for the AMB-220-E analysis set (all subjects who received at least 1 dose of study drug during the AMB-220-E study).

The 6MWT was conducted according to the American Thoracic Society guidelines (ATS statement: guidelines for the six-minute walk test. Am J Respir Crit Care Med 2002; 166(1):111-117.) Primary efficacy analyses were performed for the AMB-220-E analysis set (all subjects who received at least 1 dose of study drug during the AMB-220-E study).

The 6MWT was conducted according to the American Thoracic Society guidelines (ATS statement: guidelines for the six-minute walk test. Am J Respir Crit Care Med 2002; 166(1):111-117.) Primary efficacy analyses were performed for the AMB-220-E analysis set (all subjects who received at least 1 dose of study drug during the AMB-220-E study).

Change from baseline evaluated after 24 (baseline), 48, 108, 156, and 204 weeks of ambrisentan therapy in BDI (measured as units on a scale) immediately following exercise. Borg Dyspnea Index, a measure of perceived shortness of breath: 0 units on a scale (none) to 10 units on a scale (maximum breathlessness).

Change from baseline evaluated after 24 (baseline), 48, 108, 156, and 204 weeks of ambrisentan therapy in BDI (measured as units on a scale) immediately following exercise. Borg Dyspnea Index, a measure of perceived shortness of breath: 0 units on a scale (none) to 10 units on a scale (maximum breathlessness).

Change from baseline evaluated after 24 (baseline), 48, 108, 156, and 204 weeks of ambrisentan therapy in BDI (measured as units on a scale) immediately following exercise. Borg Dyspnea Index, a measure of perceived shortness of breath: 0 units on a scale (none) to 10 units on a scale (maximum breathlessness).

Change from baseline evaluated after 24 (baseline), 48, 108, 156, and 204 weeks of ambrisentan therapy in BDI (measured as units on a scale) immediately following exercise. Borg Dyspnea Index, a measure of perceived shortness of breath: 0 units on a scale (none) to 10 units on a scale (maximum breathlessness).

Change from baseline evaluated after 24 (baseline), 48, 108, 156, and 204 weeks of ambrisentan therapy in BDI (measured as units on a scale) immediately following exercise. Borg Dyspnea Index, a measure of perceived shortness of breath: 0 units on a scale (none) to 10 units on a scale (maximum breathlessness).

Classes: I) pulmonary hypertension (PH); ordinary physical activity not limited or causes increased dyspnea, fatigue, chest pain, or presyncope. II) PH; ordinary physical activity mildly limited and causes increased dyspnea, fatigue, chest pain, or presyncope; comfortable at rest. III) PH; physical activity markedly limited and less than ordinary physical activity causes increased dyspnea, fatigue, chest pain, or presyncope; comfortable at rest. IV) PH; physical activity causes symptoms; signs of right heart failure; dyspnea/fatigue possibly at rest.

Classes: I) PH; ordinary physical activity not limited or causes increased dyspnea, fatigue, chest pain, or presyncope. II) PH; ordinary physical activity mildly limited and causes increased dyspnea, fatigue, chest pain, or presyncope; comfortable at rest. III) PH; physical activity markedly limited and less than ordinary physical activity causes increased dyspnea, fatigue, chest pain, or presyncope; comfortable at rest. IV) PH; physical activity causes symptoms; signs of right heart failure; dyspnea/fatigue possibly at rest.

Classes: I) PH; ordinary physical activity not limited or causes increased dyspnea, fatigue, chest pain, or presyncope. II) PH; ordinary physical activity mildly limited and causes increased dyspnea, fatigue, chest pain, or presyncope; comfortable at rest. III) PH; physical activity markedly limited and less than ordinary physical activity causes increased dyspnea, fatigue, chest pain, or presyncope; comfortable at rest. IV) PH; physical activity causes symptoms; signs of right heart failure; dyspnea/fatigue possibly at rest.

Classes: I) PH; ordinary physical activity not limited or causes increased dyspnea, fatigue, chest pain, or presyncope. II) PH; ordinary physical activity mildly limited and causes increased dyspnea, fatigue, chest pain, or presyncope; comfortable at rest. III) PH; physical activity markedly limited and less than ordinary physical activity causes increased dyspnea, fatigue, chest pain, or presyncope; comfortable at rest. IV) PH; physical activity causes symptoms; signs of right heart failure; dyspnea/fatigue possibly at rest.

Classes: I) PH; ordinary physical activity not limited or causes increased dyspnea, fatigue, chest pain, or presyncope. II) PH; ordinary physical activity mildly limited and causes increased dyspnea, fatigue, chest pain, or presyncope; comfortable at rest. III) PH; physical activity markedly limited and less than ordinary physical activity causes increased dyspnea, fatigue, chest pain, or presyncope; comfortable at rest. IV) PH; physical activity causes symptoms; signs of right heart failure; dyspnea/fatigue possibly at rest.

The SGA was determined using a visual-analog scale. Subjects were asked the question, "How are you feeling today?" and were asked to draw a vertical mark on a 100-mm horizontal line in which zero represented "very poor" and 100 represented "excellent."

The SGA was determined using a visual-analog scale. Subjects were asked the question, "How are you feeling today?" and were asked to draw a vertical mark on a 100-mm horizontal line in which zero represented "very poor" and 100 represented "excellent."

The SGA was determined using a visual-analog scale. Subjects were asked the question, "How are you feeling today?" and were asked to draw a vertical mark on a 100-mm horizontal line in which zero represented "very poor" and 100 represented "excellent."

The SGA was determined using a visual-analog scale. Subjects were asked the question, "How are you feeling today?" and were asked to draw a vertical mark on a 100-mm horizontal line in which zero represented "very poor" and 100 represented "excellent."

The SGA was determined using a visual-analog scale. Subjects were asked the question, "How are you feeling today?" and were asked to draw a vertical mark on a 100-mm horizontal line in which zero represented "very poor" and 100 represented "excellent."

Clinical worsening of PAH was defined as death, lung transplantation, hospitalization for PAH, atrial septostomy, the addition of approved prostanoid therapy, or study withdrawal due to the addition of other clinically approved PAH therapeutic agents. Sildenafil, a type 5 phosphodiesterase (PDE-5) inhibitor, had not received regulatory approval for the treatment of PAH until late in the conduct of AMB 220 and AMB 220-E, and did not count toward clinical worsening. Results are presented as the Kaplan-Meier estimate (% probability) of not having clinical worsening after a given time.

Failure-free treatment status was defined as the time from initiation of active treatment to the first occurrence of death, lung transplantation, the addition of approved prostanoid therapy, or study withdrawal due to the addition of other clinically approved PAH therapeutic agents. Results are presented as the Kaplan-Meier estimate (% probability) of not having treatment failure after a given time.

Long-term survival was defined as the time from initiation of active treatment to death. Results are presented as the Kaplan-Meier estimate (% probability) of survival after a given time.

The optimized final dose from the open-label period of NCT00046319 (given QD by oral administration) was used in this study, with further dose refinement at the investigator's discretion. Subjects who completed an optional down-titration period at the end of AMB 220 were re-titrated if their final dose was 5 or 10 mg.

The optimized final dose from the open-label period of NCT00046319 (given QD by oral administration) was used in this study, with further dose refinement at the investigator's discretion. Subjects who completed an optional down-titration period at the end of AMB 220 were re-titrated if their final dose was 5 or 10 mg.

Total of all reporting groups

Baseline represents the beginning of the current extension study (ie, Week 24 of the parent study, NCT00046319).

Baseline represents the beginning of the current extension study (ie, Week 24 of the parent study, NCT00046319).

Baseline represents the beginning of the current extension study (ie, Week 24 of the parent study, NCT00046319). N=24 for the 10-mg group and N=52 for the combined ambrisentan group.

Baseline represents the beginning of the current extension study (ie, Week 24 of the parent study, NCT00046319). Borg Dyspnea Index, a measure of perceived shortness of breath: 0 units on a scale (none) to 10 units on a scale (maximum breathlessness). N=24 for the 10-mg group and N=52 for the combined ambrisentan group.

Classes: I) pulmonary hypertension (PH); ordinary physical activity not limited or causes increased dyspnea, fatigue, chest pain, or presyncope. II) PH; ordinary physical activity mildly limited and causes increased dyspnea, fatigue, chest pain, or presyncope; comfortable at rest. III) PH; physical activity markedly limited and less than ordinary physical activity causes increased dyspnea, fatigue, chest pain, or presyncope; comfortable at rest. IV) PH; physical activity causes symptoms; signs of right heart failure; dyspnea/fatigue possibly at rest.

Baseline represents the beginning of the current extension study (ie, Week 24 of the parent study, NCT00046319).

Baseline represents the beginning of the current extension study (ie, Week 24 of the parent study, NCT00046319).

Baseline represents the beginning of the current extension study (ie, Week 24 of the parent study, NCT00046319).

The optimized final dose from the open-label period of NCT00046319 (given QD by oral administration) was used in this study, with further dose refinement at the investigator's discretion.

The optimized final dose from the open-label period of NCT00046319 (given QD by oral administration) was used in this study, with further dose refinement at the investigator's discretion. Subjects who completed an optional down-titration period at the end of AMB 220 were re-titrated if their final dose was 5 or 10 mg.

The optimized final dose from the open-label period of NCT00046319 (given QD by oral administration) was used in this study, with further dose refinement at the investigator's discretion. Subjects who completed an optional down-titration period at the end of AMB 220 were re-titrated if their final dose was 5 or 10 mg.

The 6MWT was conducted according to the American Thoracic Society guidelines (ATS statement: guidelines for the six-minute walk test. Am J Respir Crit Care Med 2002; 166(1):111-117.) Primary efficacy analyses were performed for the AMB-220-E analysis set (all subjects who received at least 1 dose of study drug during the AMB-220-E study).

Primary efficacy analyses were performed for the AMB-220-E analysis set (all subjects who received at least 1 dose of study drug during the AMB-220-E study). Results are presented using the last-observation-carried-forward (LOCF) imputation.

The 6MWT was conducted according to the American Thoracic Society guidelines (ATS statement: guidelines for the six-minute walk test. Am J Respir Crit Care Med 2002; 166(1):111-117.) Primary efficacy analyses were performed for the AMB-220-E analysis set (all subjects who received at least 1 dose of study drug during the AMB-220-E study).

Primary efficacy analyses were performed for the AMB-220-E analysis set (all subjects who received at least 1 dose of study drug during the AMB-220-E study). Results are presented using the last-observation-carried-forward (LOCF) imputation.

The 6MWT was conducted according to the American Thoracic Society guidelines (ATS statement: guidelines for the six-minute walk test. Am J Respir Crit Care Med 2002; 166(1):111-117.) Primary efficacy analyses were performed for the AMB-220-E analysis set (all subjects who received at least 1 dose of study drug during the AMB-220-E study).

Primary efficacy analyses were performed for the AMB-220-E analysis set (all subjects who received at least 1 dose of study drug during the AMB-220-E study). Results are presented using the last-observation-carried-forward (LOCF) imputation.

The 6MWT was conducted according to the American Thoracic Society guidelines (ATS statement: guidelines for the six-minute walk test. Am J Respir Crit Care Med 2002; 166(1):111-117.) Primary efficacy analyses were performed for the AMB-220-E analysis set (all subjects who received at least 1 dose of study drug during the AMB-220-E study).

Primary efficacy analyses were performed for the AMB-220-E analysis set (all subjects who received at least 1 dose of study drug during the AMB-220-E study). Results are presented using the last-observation-carried-forward (LOCF) imputation.

The 6MWT was conducted according to the American Thoracic Society guidelines (ATS statement: guidelines for the six-minute walk test. Am J Respir Crit Care Med 2002; 166(1):111-117.) Primary efficacy analyses were performed for the AMB-220-E analysis set (all subjects who received at least 1 dose of study drug during the AMB-220-E study).

Primary efficacy analyses were performed for the AMB-220-E analysis set (all subjects who received at least 1 dose of study drug during the AMB-220-E study). Results are presented using the last-observation-carried-forward (LOCF) imputation.

Change from baseline evaluated after 24 (baseline), 48, 108, 156, and 204 weeks of ambrisentan therapy in BDI (measured as units on a scale) immediately following exercise. Borg Dyspnea Index, a measure of perceived shortness of breath: 0 units on a scale (none) to 10 units on a scale (maximum breathlessness).

Primary efficacy analyses were performed for the AMB-220-E analysis set (all subjects who received at least 1 dose of study drug during the AMB-220-E study). Results are presented using the last-observation-carried-forward (LOCF) imputation.

Change from baseline evaluated after 24 (baseline), 48, 108, 156, and 204 weeks of ambrisentan therapy in BDI (measured as units on a scale) immediately following exercise. Borg Dyspnea Index, a measure of perceived shortness of breath: 0 units on a scale (none) to 10 units on a scale (maximum breathlessness).

Primary efficacy analyses were performed for the AMB-220-E analysis set (all subjects who received at least 1 dose of study drug during the AMB-220-E study). Results are presented using the last-observation-carried-forward (LOCF) imputation.

Change from baseline evaluated after 24 (baseline), 48, 108, 156, and 204 weeks of ambrisentan therapy in BDI (measured as units on a scale) immediately following exercise. Borg Dyspnea Index, a measure of perceived shortness of breath: 0 units on a scale (none) to 10 units on a scale (maximum breathlessness).

Primary efficacy analyses were performed for the AMB-220-E analysis set (all subjects who received at least 1 dose of study drug during the AMB-220-E study). Results are presented using the last-observation-carried-forward (LOCF) imputation.

Change from baseline evaluated after 24 (baseline), 48, 108, 156, and 204 weeks of ambrisentan therapy in BDI (measured as units on a scale) immediately following exercise. Borg Dyspnea Index, a measure of perceived shortness of breath: 0 units on a scale (none) to 10 units on a scale (maximum breathlessness).

Primary efficacy analyses were performed for the AMB-220-E analysis set (all subjects who received at least 1 dose of study drug during the AMB-220-E study). Results are presented using the last-observation-carried-forward (LOCF) imputation.

Change from baseline evaluated after 24 (baseline), 48, 108, 156, and 204 weeks of ambrisentan therapy in BDI (measured as units on a scale) immediately following exercise. Borg Dyspnea Index, a measure of perceived shortness of breath: 0 units on a scale (none) to 10 units on a scale (maximum breathlessness).

Primary efficacy analyses were performed for the AMB-220-E analysis set (all subjects who received at least 1 dose of study drug during the AMB-220-E study). Results are presented using the last-observation-carried-forward (LOCF) imputation.

Classes: I) pulmonary hypertension (PH); ordinary physical activity not limited or causes increased dyspnea, fatigue, chest pain, or presyncope. II) PH; ordinary physical activity mildly limited and causes increased dyspnea, fatigue, chest pain, or presyncope; comfortable at rest. III) PH; physical activity markedly limited and less than ordinary physical activity causes increased dyspnea, fatigue, chest pain, or presyncope; comfortable at rest. IV) PH; physical activity causes symptoms; signs of right heart failure; dyspnea/fatigue possibly at rest.

Primary efficacy analyses were performed for the AMB-220-E analysis set (all subjects who received at least 1 dose of study drug during the AMB-220-E study). Results are presented using the last-observation-carried-forward (LOCF) imputation.

Classes: I) PH; ordinary physical activity not limited or causes increased dyspnea, fatigue, chest pain, or presyncope. II) PH; ordinary physical activity mildly limited and causes increased dyspnea, fatigue, chest pain, or presyncope; comfortable at rest. III) PH; physical activity markedly limited and less than ordinary physical activity causes increased dyspnea, fatigue, chest pain, or presyncope; comfortable at rest. IV) PH; physical activity causes symptoms; signs of right heart failure; dyspnea/fatigue possibly at rest.

Classes: I) PH; ordinary physical activity not limited or causes increased dyspnea, fatigue, chest pain, or presyncope. II) PH; ordinary physical activity mildly limited and causes increased dyspnea, fatigue, chest pain, or presyncope; comfortable at rest. III) PH; physical activity markedly limited and less than ordinary physical activity causes increased dyspnea, fatigue, chest pain, or presyncope; comfortable at rest. IV) PH; physical activity causes symptoms; signs of right heart failure; dyspnea/fatigue possibly at rest.

Primary efficacy analyses were performed for the AMB-220-E analysis set (all subjects who received at least 1 dose of study drug during the AMB-220-E study). Results are presented using the last-observation-carried-forward (LOCF) imputation.

Classes: I) PH; ordinary physical activity not limited or causes increased dyspnea, fatigue, chest pain, or presyncope. II) PH; ordinary physical activity mildly limited and causes increased dyspnea, fatigue, chest pain, or presyncope; comfortable at rest. III) PH; physical activity markedly limited and less than ordinary physical activity causes increased dyspnea, fatigue, chest pain, or presyncope; comfortable at rest. IV) PH; physical activity causes symptoms; signs of right heart failure; dyspnea/fatigue possibly at rest.

Primary efficacy analyses were performed for the AMB-220-E analysis set (all subjects who received at least 1 dose of study drug during the AMB-220-E study). Results are presented using the last-observation-carried-forward (LOCF) imputation.

Classes: I) PH; ordinary physical activity not limited or causes increased dyspnea, fatigue, chest pain, or presyncope. II) PH; ordinary physical activity mildly limited and causes increased dyspnea, fatigue, chest pain, or presyncope; comfortable at rest. III) PH; physical activity markedly limited and less than ordinary physical activity causes increased dyspnea, fatigue, chest pain, or presyncope; comfortable at rest. IV) PH; physical activity causes symptoms; signs of right heart failure; dyspnea/fatigue possibly at rest.

Primary efficacy analyses were performed for the AMB-220-E analysis set (all subjects who received at least 1 dose of study drug during the AMB-220-E study). Results are presented using the last-observation-carried-forward (LOCF) imputation.

The SGA was determined using a visual-analog scale. Subjects were asked the question, "How are you feeling today?" and were asked to draw a vertical mark on a 100-mm horizontal line in which zero represented "very poor" and 100 represented "excellent."

Primary efficacy analyses were performed for the AMB-220-E analysis set (all subjects who received at least 1 dose of study drug during the AMB-220-E study).

The SGA was determined using a visual-analog scale. Subjects were asked the question, "How are you feeling today?" and were asked to draw a vertical mark on a 100-mm horizontal line in which zero represented "very poor" and 100 represented "excellent."

Primary efficacy analyses were performed for the AMB-220-E analysis set (all subjects who received at least 1 dose of study drug during the AMB-220-E study). Results are presented using the last-observation-carried-forward (LOCF) imputation.

The SGA was determined using a visual-analog scale. Subjects were asked the question, "How are you feeling today?" and were asked to draw a vertical mark on a 100-mm horizontal line in which zero represented "very poor" and 100 represented "excellent."

Primary efficacy analyses were performed for the AMB-220-E analysis set (all subjects who received at least 1 dose of study drug during the AMB-220-E study). Results are presented using the last-observation-carried-forward (LOCF) imputation.

The SGA was determined using a visual-analog scale. Subjects were asked the question, "How are you feeling today?" and were asked to draw a vertical mark on a 100-mm horizontal line in which zero represented "very poor" and 100 represented "excellent."

Primary efficacy analyses were performed for the AMB-220-E analysis set (all subjects who received at least 1 dose of study drug during the AMB-220-E study). Results are presented using the last-observation-carried-forward (LOCF) imputation.

The SGA was determined using a visual-analog scale. Subjects were asked the question, "How are you feeling today?" and were asked to draw a vertical mark on a 100-mm horizontal line in which zero represented "very poor" and 100 represented "excellent."

Primary efficacy analyses were performed for the AMB-220-E analysis set (all subjects who received at least 1 dose of study drug during the AMB-220-E study). Results are presented using the last-observation-carried-forward (LOCF) imputation.

Clinical worsening of PAH was defined as death, lung transplantation, hospitalization for PAH, atrial septostomy, the addition of approved prostanoid therapy, or study withdrawal due to the addition of other clinically approved PAH therapeutic agents. Sildenafil, a type 5 phosphodiesterase (PDE-5) inhibitor, had not received regulatory approval for the treatment of PAH until late in the conduct of AMB 220 and AMB 220-E, and did not count toward clinical worsening. Results are presented as the Kaplan-Meier estimate (% probability) of not having clinical worsening after a given time.

The NCT00046319 analysis set (all subjects who received at least 1 dose of study drug during the AMB-220 study) was evaluated during the NCT00046319 and AMB-220-E study periods.

Failure-free treatment status was defined as the time from initiation of active treatment to the first occurrence of death, lung transplantation, the addition of approved prostanoid therapy, or study withdrawal due to the addition of other clinically approved PAH therapeutic agents. Results are presented as the Kaplan-Meier estimate (% probability) of not having treatment failure after a given time.

The NCT00046319 analysis set (all subjects who received at least 1 dose of study drug during the NCT00046319 study) was evaluated during the NCT00046319 and AMB-220-E study periods.

Long-term survival was defined as the time from initiation of active treatment to death. Results are presented as the Kaplan-Meier estimate (% probability) of survival after a given time.

The AMB-220-E analysis set (all subjects who received at least 1 dose of study drug during the AMB-220-E study) was evaluated during the AMB-220-E study period.

The number of participants in the AMB-220-E analysis set who experienced AEs (including serious AEs) of moderate severity (ie, interfered with routine activities and subject may have experienced significant discomfort) that began after entering AMB-220-E (treatment-emergent AEs) and that occurred in more than 1 participant are summarized by dose group. The AMB-220-E analysis set consisted of all participants who received at least 1 dose of study drug during the AMB-220-E study.

The AMB-220-E population consisted of all subjects who received at least 1 dose of study drug during the AMB-220-E study.

The number of participants in the AMB-220-E analysis set who experienced AEs (including serious AEs) of mild severity (ie, did not interfere with routine activities and the subject may have experienced slight discomfort) that began after entering AMB-220-E (treatment-emergent AEs) and that occurred in more than 1 participant are summarized by dose group. The AMB-220-E analysis set consisted of all participants who received at least 1 dose of study drug during the AMB-220-E study.

The AMB-220-E population consisted of all subjects who received at least 1 dose of study drug during the AMB-220-E study.

The optimized final dose from the open-label period of NCT00046319 (given QD by oral administration) was used in this study, with further dose refinement at the investigator's discretion.

The optimized final dose from the open-label period of NCT00046319 (given QD by oral administration) was used in this study, with further dose refinement at the investigator's discretion. Subjects who completed an optional down-titration period at the end of AMB 220 were re-titrated if their final dose was 5 or 10 mg.

The optimized final dose from the open-label period of NCT00046319 (given QD by oral administration) was used in this study, with further dose refinement at the investigator's discretion. Subjects who completed an optional down-titration period at the end of AMB 220 were re-titrated if their final dose was 5 or 10 mg.