Astex Pharmaceuticals to Present a Novel Targeted Approach to the Treatment of HCV at the AASLD Meeting

Astex Pharmaceuticals, Inc. (NASDAQ:ASTX), a pharmaceutical company dedicated to the discovery, development and commercialization of novel therapeutics, announced that it will present data on its novel, first-in-class direct acting antiviral agents (DAA) against Hepatitis C Virus (HCV) at the 62^nd Annual Meeting of the American Association for the Study of Liver Diseases (AASLD) in San Francisco, November 4-8, 2011.

The following presentations are scheduled for Saturday, November 5, 2011 at 2:00 pm PT during poster session R06: HCV Therapy: Preclinical and Early Clinical Development.

• Abstract #371: Cell based replicon validation of novel HCV NS3 allosteric inhibitors result in a new therapeutic approach
• Abstract #352: Discovery of a novel allosteric binding site on the full length HCV NS3/4a enzyme by fragment-based X-ray screening

Astex Pharmaceuticals has used its proprietary fragment-based drug discovery approach, Pyramid™, to target a previously unknown allosteric binding site on the full length HCV NS3 protease - helicase complex. Agents acting at this site have a novel mode of action and a different resistance profile compared to NS3 protease inhibitors. The NS3 protein is essential for viral replication and represents a validated HCV therapeutic target. These data represent a new approach to development of targeted agents to treat HCV infection. As part of its presentations, Astex Pharmaceuticals scientists will present on the discovery of the allosteric site using their Pyramid approach and on initial work aimed at validating the anti-viral activity of these first-in-class fragment-derived allosteric inhibitors.

Astex Pharmaceuticals is currently selecting a clinical candidate with a view to filing an IND in 2012. This research program, which has been supported with £2 million of funding from the Wellcome Trust Seeding Drug Discovery initiative, is wholly owned by Astex Pharmaceuticals.

About Astex Pharmaceuticals

Astex Pharmaceuticals is dedicated to the discovery, development, and commercialization of novel therapeutics with a focus on cancer. The Company is developing a proprietary pipeline of novel cancer therapies, will selectively in-license assets possessing a strategic fit with an attractive cost – value ratio, and is creating de-risked products for partnership with leading pharmaceutical companies. Astex Pharmaceuticals, formerly SuperGen, developed Dacogen® (decitabine) for Injection and receives significant royalties on global sales.

For more information about Astex Pharmaceuticals, Inc., please visit http://www.astx.com.