The US Food and Drug Administration today approved combining ambrisentan (Letairis/Gilead) with tadalafil to treat pulmonary arterial hypertension.
The US Food and Drug Administration today approved combining ambrisentan (Letairis/Gilead) with tadalafil to treat pulmonary arterial hypertension (PAH). The combination is meant to "reduce the risks of disease progression and hospitalization for worsening PAH, and to improve exercise ability," the company said.
Ambrisentan is an endothelin receptor antagonist. It was first approved in 2007 as a monotherapy for PAH.
Tadalafil is a PDE5 inhibitor that in 2009 was also approved to improve the ability of patients with PAH to engage in exercise.
The new labeling is supported by data from a study called AMBITION, a randomized double-blind multicenter study in which participants got both drugs.
Data from AMBITION were published in
The New England Journal of Medicine
and Letairis plus tadalafil was the only recommended initial combination therapy option for PAH in the “2015
European Society of Cardiology
/ European Respiratory Society Guidelines for the Diagnosis and Treatment of Pulmonary Hypertension” published in the
European Heart Journal
PAH is a debilitating disease characterized by constriction of the blood vessels in the lungs leading to high pulmonary arterial pressures. These high pressures make it difficult for the heart to pump blood through the lungs to be oxygenated. Patients with PAH suffer from shortness of breath as the heart struggles to pump against these high pressures, causing such patients to ultimately die of heart failure. PAH can occur with no known underlying cause, or it can occur secondary to diseases such as connective tissue disease, congenital heart defects, cirrhosis of the liver and HIV infection.
Ambrisentan should not be taken during pregnancy as it is toxic to fetuses.