Study of combination therapy versus monotherapy for pulmonary arterial hypertension

Gilead Sciences, Inc. (Nasdaq:GILD), in collaboration with GlaxoSmithKline (GSK), today announced plans for an international, event-driven (morbidity and mortality) clinical trial to study combination therapy versus monotherapy in a first-line treatment setting for pulmonary arterial hypertension (PAH). The study, AMBITION (a randomized, double-blind, multicenter study of first-line combination therapy with AMBrIsentan and Tadalafil in subjects with pulmonary arterial hypertensION), will evaluate first-line combination use with ambrisentan, an endothelin receptor antagonist (ERA) and tadalafil, a PDE5 inhibitor, in patients with PAH. Ambrisentan is approved under the tradename Letairis^® (ambrisentan 5 mg and 10 mg tablets) 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.

“The question of first-line combination therapy versus monotherapy is one of the most important outstanding clinical questions in PAH,” said Lewis J. Rubin, MD, Professor of Medicine, University of California, San Diego. “As the first large, randomized clinical trial to address the efficacy of initial combination therapy in PAH, AMBITION has the potential to be a landmark study.”

AMBITION will be a double-blind, multicenter study, in which more than 300 treatment-naive PAH patients will be randomized to receive either the combination of ambrisentan and tadalafil or monotherapy (ambrisentan or tadalafil). Gilead and GSK are working with regulatory agencies and the PAH research community to finalize details of the study and plan to begin enrollment in 2010.