Otsuka Pharmaceutical acquired Astex Pharmaceuticals through an all-cash tender offer at $8.50 per share, a roughly 48% premium that valued the company at approximately $886M on a fully diluted basis. The transaction was announced on September 5, 2013; the tender offer closed October 10 and the merger completed October 11, 2013. It added Astex's fragment-based PYRAMID drug discovery platform and its oncology portfolio, including the DACOGEN (decitabine) franchise, to Otsuka's pipeline.