Amgen Inc. said on Monday that will sell its Japanese unit to Takeda Pharmaceutical, Japan’s largest drugmaker, in a deal that could eventually total $902 million.

Takeda will become Amgen’s worldwide partner in commercializing motesanib diphosphate, which is in mid-stage clinical trials to treat breast, lung and thyroid cancers, the Thousand Oaks-based biotech firm said. Takeda also obtains rights to develop for the Japanese market up to 13 experimental drugs from Amgen’s pipeline.

Takeda plans to acquire all the shares of Amgen’s Japanese subsidiary, Amgen KK. Financial terms for the entire deal include an upfront cash payment to Amgen of $200 million. Takeda also will pay Amgen up to $340 million in expected worldwide development costs over the next several years, $362 million in success-based milestone payments and double-digit royalties on sales in Japan.

The deal could help Amgen cut costs as it recovers from a sales slump in its anemia drugs following safety concerns. After a brief spike after the markets opened, Amgen shares were down 2 cents to $47.37 in afternoon trading on the Nasdaq.

Shares may have been affected by news that President Bush’s proposed federal budget for fiscal 2009 includes new funds to speed regulatory review of generic pharmaceuticals that could compete with Amgen’s earliest drugs, Epogen and Neupogen.