FOSTER CITY, Calif.--(BUSINESS WIRE)--Gilead Sciences, Inc. (Nasdaq:GILD) today announced the initiation of ATHENA-1, a Phase IV, randomized, double-blind, placebo-controlled study evaluating Letairis® (ambrisentan 5 mg and 10 mg tablets) in patients with pulmonary arterial hypertension (PAH) demonstrating a sub-optimal response to sildenafil monotherapy. ATHENA-1 is the first of several Phase IV Letairis studies Gilead plans to initiate in 2008 and 2009. Letairis is currently approved as a once-daily treatment for PAH (WHO Group 1) in patients with WHO functional class II or III symptoms to improve exercise capacity and delay clinical worsening.
