ARIES - Ambrisentan in Patients With Moderate to Severe Pulmonary Arterial Hypertension (PAH)

ARIES-1 in North America and Australia ARIES-2 in Western and Eastern Europe, South America and Israel Subjects in these randomized studies will receive one of two doses of ambrisentan or placebo. Inclusion is not based on a specified WHO functional classification. Rather, subjects with WHO Class I-IV symptoms are eligible if their 6-minute walk distance is 150-450 meters and they meet the study-specified hemodynamic criteria. Subjects with anorexigen or HIV infection related PAH are eligible but subjects with congenital heart disease and pediatric subjects are excluded. The study requires a historical cardiac catheterization and other diagnostic procedures.