AMBRISENTAN RESCUE THERAPY IN PATIENTS WITH PULMONARY ARTERIAL HYPERTENSION WHO DISCONTINUED BOSENTAN OR SITAXSENTAN DUE TO LIVER FUNCTION ABNORMALITIES

Abstract

PURPOSE: Ambrisentan is a high affinity, propanoic acid-class, ETA-selective endothelin receptor antagonist (ERA) with once-daily oral doses that are 10-100 times lower than sulfonamide-class ERAs for pulmonary arterial hypertension (PAH). Ambrisentan doses of 2.5 and 5 mg once-daily have been shown to improve 6-minute walk distance (6MWD) and delay clinical worsening in a placebo-controlled study of patients with PAH (ARIES-2), with no incidence of serum aminotransferases >3xULN (LFT abnormalities). To further evaluate the safety of ambrisentan, an open-label study was conducted of patients who had previously discontinued bosentan, sitaxsentan, or both therapies due to LFT abnormalities.