Daiichi Sankyo, a Japan-based pharmaceutical, will acquire all outstanding common stock of Ambit Biosciences for $15 per share in cash through a tender offer, followed by a merger with a subsidiary of Daiichi Sankyo, or approximately $315 million on a fully diluted basis.

Each Ambit Biosciences stockholder will receive one Contingent Value Right (CVR), entitling the holder to receive an additional cash payment of up to $4.50 for each share he/she owns if certain commercialization-related milestones are achieved. The total transaction is valued at up to $410 million on a fully diluted basis.

Ambit Biosciences, a publicly traded San Diego-based biopharmaceutical company, is focused on the discovery and development of medicines to treat unmet medical needs in oncology, autoimmune and inflammatory diseases by inhibiting enzymes that are important drivers for those diseases.

The lead Ambit Biosciences drug candidate, quizartinib, currently is in phase III clinical trials among patients with acute myeloid leukemia (AML) who express a genetic mutation in FLT3 and who are refractory to or relapsed after first-line treatment with or without hematopoietic stem cell transplantation (HSCT) consolidation. AML patients with the FLT3 mutation tend to have a poorer prognosis than those whose cancers are FLT3 negative.

Joji Nakayama, Daiichi Sankyo president and CEO, said, "Long-term success in oncology depends upon three pillars: fostering development of our in-house molecules, exploring mutually beneficial partnerships and executing strategic purchases, such as Ambit Biosciences, which follows our acquisitions of U3 Pharma and Plexxikon."

Mahmoud Ghazzi, M.D., Ph.D., global head of development for Daiichi Sankyo, said, "With the acquisition of Ambit Biosciences, Daiichi Sankyo gains additional opportunities to develop promising treatments for cancer, including the global rights to quizartinib, currently being studied in patients with refractory AML, a very serious condition for which no new therapies have been approved for more than 30 years."