Astex was founded in 1999 in Cambridge, UK, to pioneer the development of fragment-based drug discovery technology.

Astex was backed by leading venture capital firms and established multiple partnerships with major pharmaceutical companies including AstraZeneca, Novartis, Janssen and GSK to use the company’s drug discovery platform, Pyramid^TM, to identify novel small molecule drugs addressing key disease targets.

In 2011 the company merged with the US company, SuperGen, Inc. which was formed in 1991 in Emeryville, California, and was the developer of the oncology drug Dacogen^® (decitabine) for injection. Shortly after the merger, SuperGen, Inc., changed its name to Astex Pharmaceuticals Inc., reflecting the strength of the ‘Astex’ brand created by the UK Company.

Astex Pharmaceuticals Inc., was acquired by Otsuka in October 2013 and operated from its two sites in the US and UK until January 2024 when the US site became a wholly owned subsidiary of Taiho Oncology Inc. This reorganisation consolidated the oncology clinical development expertise and operations within a single organisation within the Otsuka group.

Astex continues to operate its drug discovery and preclinical development business, which is headquartered in Cambridge, UK, as an independent wholly owned subsidiary of Otsuka Pharmaceutical Co. Ltd., trading as ‘Astex Pharmaceuticals’.