Gilead Sciences and Phenex Pharmaceuticals AG, a privately-held biotechnology company, have signed a definitive agreement under which Gilead will acquire Phenex's Farnesoid X Receptor (FXR) programme comprising small molecule FXR agonists for the treatment of liver diseases including nonalcoholic steatohepatitis (NASH).

Under the terms of the agreement, Gilead will pay Phenex an upfront payment plus additional payments based upon achievement of certain development milestones that may potentially be worth up to $470 million.

NASH is a common, serious chronic liver disease characterised by inflammation and excessive fat accumulation in the liver and may lead to progressive fibrosis, cirrhosis and liver failure. NASH is estimated to affect 10 to 20 percent of people in the developed world. There are currently no approved therapies to treat NASH. FXR is a nuclear hormone receptor that regulates bile acid, lipid and glucose homeostasis, which can help reduce liver steatosis and inflammation, and may help prevent liver fibrosis.

"This agreement represents a significant milestone for our company and for the field of liver disease research," said Dr. Claus Kremoser, chief executive officer, of Phenex Pharmaceuticals AG. "After 15 years of research, FXR is now one of the few clinically validated targets for NASH and we are delighted that Gilead will be continuing the research necessary to more fully realise its potential for advanced liver disease."

"The acquisition of Phenex's FXR programme represents an important opportunity to accelerate Gilead's efforts to develop new treatment options that address fibrotic liver diseases," said Norbert W. Bischofberger, Gilead's executive vice president, research and development and chief scientific officer. "We look forward to working closely with Phenex's research and development team to advance the FXR programme into clinical development as quickly as possible to explore its potential in areas of significant unmet need."

Phenex is a small private German biotechnology company founded in 2002 and located in Ludwigshafen, Germany, with a research site in Heidelberg. Phenex has a long history in nuclear receptor drug discovery and has emerged as a highly specialised leader in the field of difficult to target emerging nuclear receptor targets.