Ambrisentan

Ambrisentan was first approved by the U.S. Food and Drug Administration (FDA) on Jun 15, 2007, then approved by the European Medicines Agency (EMA) on Apr 21, 2008 and approved by Pharmaceuticals and Medical Devices Agency of Japan (PMDA) on Jul 23, 2010. In 2000, Abbott, originator of ambrisentan, granted Myogen (acquired by Gilead in 2006) a license to the compound for the treatment of PAH. In 2006, GlaxoSmithKline obtained worldwide rights to market the compound for PAH worldwide, with the exception of the U.S. It is marketed as Letairis^® by Gilead in US.

Ambrisentan is an endothelin receptor antagonist, and is selective for the type A endothelin receptor (ETA). It is indicated for the treatment of pulmonary arterial hypertension (PAH) (WHO Group 1) to improve exercise ability and delay clinical worsening. Studies establishing effectiveness included predominantly patients with WHO Functional Class II-III symptoms and etiologies of idiopathic or heritable PAH (64%) or PAH associated with connective tissue diseases (32%).

Letairis^® is available as film-coated tablet for oral use, containing 5 or 10 mg of free Ambrisentan. The recommended starting dose is 5 mg once daily with or without food, and increase the dose to 10 mg once daily if 5 mg is tolerated.