The purpose of this study is to evaluate the safety and efficacy of Thelin™ (sitaxsentan sodium) as compared to placebo in the treatment of patients with PAH. A cohort of patients will be randomized to usual treatment with Tracleer® (bosentan) for observational comparisons of safety and efficacy.
The purpose of this study is to evaluate the safety and efficacy of Thelin™ (sitaxsentan sodium) compared to placebo (sugar pill) in the treatment of patients with pulmonary arterial hypertension (PAH).