FDA approves Gilead's Letairis with tadalafil for PAH

Gilead Sciences (Nasdaq: GILD), now the world’s largest biotech firm by sales, said on Friday that US Food and Drug Administration has approved the use of its Letairis (ambrisentan) in combination with tadalafil for the treatment of pulmonary arterial hypertension (PAH) (WHO Group 1) 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 USA as monotherapy for PAH to improve exercise ability and delay clinical worsening. Tadalafil, the active ingredient of Adcirca from Eli Lilly, is a PDE5 inhibitor that was initially approved for PAH in the US 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 Oudiz, 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 today's 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."