Study of Add-on Ambrisentan Therapy to Background Phosphodiesterase Type-5 Inhibitor (PDE5i) Therapy in Pulmonary Arterial Hypertension (ATHENA-1)

Inclusion Criteria

• •Must be between 16 and 75 years of age;
• •Must weigh at least 40 kg;
• •Have a current diagnosis of idiopathic PAH, familial PAH, or PAH that is primarily due to connective tissue disease, congenital heart defects, drug or toxin use, or human immunodeficiency virus (HIV);
• •Have WHO functional class III symptoms;
• •Be receiving sildenafil or tadalafil monotherapy for the treatment of PAH for at least the past 12 weeks and at a stable dose for at least 8 consecutive weeks;
• •Meet all of the following hemodynamic criteria by means of a right heart catheterization: mPAP of at least 25 mmHg; PVR of at least 400 dyne\*sec/cm5; pulmonary capillary wedge pressure (PCWP) or left ventricular end diastolic pressure (LVEDP) of not more than 15 mmHg;
• •Meet all of the following pulmonary function test criteria no more than 12 weeks before the screening visit: total lung capacity at least 60% of predicted normal and forced expiratory volume in 1 second of at least 65% of predicted normal;
• •Able to walk at least 150 meters during the screening 6-minute walk test (6MWT);
• •If receiving calcium channel blockers or 5-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors (i.e., statins) must be on stable therapy for at least 4 weeks;
• •If diagnosed with HIV, must have stable disease status.