Astex Pharmaceuticals Inc. (NASDAQ:ASTX) ended the week up 33% on the announcement that the Otsuka Pharmaceutical Co. Ltd. subsidiary of Otsuka Holdings Co. Ltd. (Tokyo:4478) will acquire the biotech for $8.50 per share in cash, or $866 million. Astex shares are up nearly 200% since its formation from the merger between Astex Therapeutics Ltd. and SuperGen Inc. in July 2011.

Over the last two years, Astex has made good on Chairman and CEO James Manuso's goal outlined at the time of the merger of becoming a mid-tier cancer play valued between $500 million and $1 billion. Astex's market cap after the deal was $272.8 million.