Cardiopulmonary Therapies
Endothelin is a small peptide hormone believed to play a critical role in the regulation of blood flow and cell division. Elevated endothelin blood levels are associated with several cardiovascular disease conditions, including pulmonary arterial hypertension (PAH) and resistant hypertension. Two endothelin receptor antagonists, ambrisentan for the treatment of PAH and darusentan for the treatment of resistant hypertension, are the foundation of Gilead’s cardiopulmonary development portfolio and resulted from the acquisition of Myogen.
Through our acquisition of Myogen, we also gained commercialization rights for Flolan in the United States. Developed by GSK, Flolan is a synthetic chemical similar to prostacyclin, a naturally occurring chemical in the body that helps regulate the size or diameter of blood vessels. It was approved in 1995 for the long-term intravenous treatment of primary pulmonary hypertension. This product has provided an important opportunity for our U.S.-based specialty sales team to gain experience selling products in the field of PAH.
Through its March 2006 agreement with Myogen, GSK holds the rights to commercialize ambrisentan in territories outside of the United States, where GSK currently markets Flolan.
Current therapeutic options for PAH are limited, and there remains an unmet need for safe and effective new treatments. In December 2006, we submitted a New Drug Application (NDA) to the U.S. FDA for ambrisentan as a treatment for PAH. In February 2007, the U.S. FDA granted priority review of the NDA, giving ambrisentan an estimated six-month review. The compound has been granted orphan drug status as a treatment for PAH in the United States and the European Union. If approved, we believe that ambrisentan has the profile to become the endothelin receptor antagonist of choice for the treatment of PAH.
Another candidate in development, darusentan, is currently being evaluated in Phase III clinical trials as a potential treatment for resistant hypertension.
