The U.S. Food and Drug Administration has approved the use of Letairis (ambrisentan) in combination with tadalafil for the treatment of pulmonary arterial hypertension (PAH) to reduce the risks of disease progression and hospitalization for worsening PAH, and to improve exercise ability. Letairis is an endothelin receptor antagonist that was first approved in 2007 in the U.S. as monotherapy for PAH to improve exercise ability and delay clinical worsening. Tadalafil is a PDE5 inhibitor that was initially approved for PAH in the U.S. in 2009 to improve exercise ability.

“The evidence to support the use of ambrisentan and tadalafil in PAH is well-established, however an outstanding question has been whether combining these two medications up front may further delay the progression of this disease over the long term for patients who are newly starting PAH therapy,” said Ronald J. Oudiz, MD, Professor of Medicine, David Geffen School of Medicine at UCLA and Director, Liu Center for Pulmonary Hypertension, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center. “Based on the data supporting the approval approval, we now know that patients receiving ambrisentan and tadalafil up front are less likely to experience disease progression or be hospitalized, and have more improvement in exercise ability than patients receiving either effective therapy alone. As such, this combination represents a new treatment strategy for patients living with this debilitating and life-threatening disease.”

The new labeling is supported by data from the AMBITION study (a randomized, double-blind, multicenter study of first-line combination therapy with Ambrisentan and Tadalafil in patients with pulmonary arterial hypertension).

AMBITION was cosponsored by Gilead and GlaxoSmithKline (GSK). Eli Lilly and Company also provided funding and tadalafil drug supply for the trial.

Gilead commercializes ambrisentan under the trade name Letairis in the U.S. and GSK commercializes ambrisentan under the tradename Volibris in territories outside of the U.S.