ARTEMIS-PH - Study of Ambrisentan in Subjects With Pulmonary Hypertension Associated With Idiopathic Pulmonary Fibrosis

Selected Inclusion Criteria: * Weight ≥ 40 kg at screening * Diagnosis of IPF based on modified American Thoracic Society-European Respiratory Society guidelines * Diagnosis of PH based on the following hemodynamic requirements: mean pulmonary artery pressure (mPAP ≥ 25 mm Hg; pulmonary vascular resistance \> 240 dyne.sec/cm\^5; pulmonary capillary wedge pressure or left ventricular end-diastolic pressure ≤ 15 mm Hg * Forced vital capacity (FVC) ≥ 40% * Able to walk at least 50 meters during two 6-minute walk tests * If receiving calcium channel blockers, low-dose oral corticosteroids, immunosuppressive, cytoxic, or antifibrotic drugs dose must have been stable. Selected Exclusion Criteria: * Diagnosis of PH primarily due to an etiology other than IPF * Surgical lung biopsy diagnosis other than Usual Interstitial Pneumonia * Other known cause of interstitial lung disease * Evidence of significant obstructive lung disease * Recent hospitalization for an acute exacerbation of IPF * Recent active pulmonary or upper respiratory tract infection * Left ventricular ejection fraction \< 40% * Serum creatinine ≥ 2.5 mg/dL * Required hemodialysis, peritoneal dialysis, or hemofiltration * Female subject who was pregnant or breastfeeding * Recent treatment for PH with an endothelin receptor antagonist (ERA), phosphodiesterase type 5 inhibitor, or prostacyclin derivative * Recent treatment with high dose oral corticosteroids * Recent treatment (within 4 weeks prior to screening) with imatinib mesylate (Gleevec) * Alanine aminotransferase or aspartate aminotransferase lab value that was greater than 1.5 x the upper limit of the normal range * Discontinued other ERA treatment for any adverse reaction other than those associated with liver function test abnormalities