Sitaxsentan Efficacy And Safety Trial With A Randomized Prospective Assessment Of Adding Sildenafil (SR-PAAS)

Number of Participants With Change From Baseline in World Health Organization (WHO) Functional Classification at Weeks 4, 8 and 12

WHO functional classification for PAH ranges from Class I (no limitation in physical activity, no dyspnea with normal activity) to Class IV (cannot perform a physical activity without any symptoms, dyspnea at rest). Improvement = reduction in functional class, deterioration = increase in functional class, no change = no change in functional class.

Time frame: Baseline, Weeks 4, 8 and 12 or Early Termination (ET)

Time to Clinical Worsening (TTCW)

TTCW defined as the number of days between first dose of study drug and the occurrence of a predefined clinical worsening event. Predefined clinical worsening events included: hospitalization for worsening PAH, on-study death, heart-lung or lung transplant, atrial septostomy or withdrawal due to the addition of any chronic medications for the treatment of worsening PAH.

Time frame: Baseline, Weeks 4, 8 and 12 or ET