Gilead, GSK Collaborate On Phase IV Clinical Trial Of PAH

Gilead Sciences (Gilead), in collaboration with GlaxoSmithKline (GSK) has 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 is expected to evaluate first-line combination use with ambrisentan, and tadalafil, a PDE5 inhibitor, in patients with PAH. Ambrisentan, an endothelin receptor antagonist (ERA) is approved under the tradename Letairis (ambrisentan 5mg and 10mg 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 company said that AMBITION will be a double-blind, multicenter study, in which more than 300 treatment-naive PAH patients will be randomised 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 finalise details of the study and plan to begin enrollment in 2010.

Lewis Rubin, professor of medicine at University of California, said: “The question of first-line combination therapy versus monotherapy is one of the most important outstanding clinical questions in PAH. As the first large, randomised clinical trial to address the efficacy of initial combination therapy in PAH, AMBITION has the potential to be a landmark study.”