Daiichi Sankyo Co. has agreed to buy U.S.-based Ambit Biosciences Corp. for as much as $410 million to bolster its pipeline of cancer treatments.

The Tokyo-based drugmaker will pay $15 in cash per share, it said in a statement Monday to the Tokyo Stock Exchange.

Ambit stockholders will have the right to receive an additional payment of as much as $4.50 for each share they own if certain milestones are achieved.

Ambit's lead drug candidate, called quizartinib, is currently in late-stage trials in patients with acute myeloid leukemia (AML).

Global drug companies have announced a string of deals this year, pruning underperforming businesses and making acquisitions in areas where demand for medicines is growing.

AML is the most common type of acute leukemia in adults and is projected to account for about 36 percent of all new leukemia cases in 2014, the companies said. The condition results in uncontrolled growth of malignant white blood cells.

"The acquisition of Ambit Biosciences further builds our presence in oncology to ensure we are delivering on our goal of providing world-class, innovative pharmaceuticals in core areas of unmet medical need," Daiichi Sankyo President and Chief Executive Officer Joji Nakayama said in the statement.

The Japanese drugmaker agreed earlier this year to sell its Indian unit, Ranbaxy Laboratories Ltd., to Sun Pharmaceutical Industries Ltd.

Daiichi Sankyo had struggled to improve manufacturing conditions at Ranbaxy and saw its own share price fall as U.S. regulators imposed restrictions on imports from several Ranbaxy factories.