Dec. 11 (Bloomberg) -- Amgen Inc., the world's biggest biotechnology company, may sell its unit in Japan as part of global cost cuts to offset a slump in sales and a lower earnings forecast, people familiar with the plan said.

Amgen asked for bids of more than 45 billion yen ($403 million) for Tokyo-based Amgen K.K. during negotiations with Japanese drugmakers, said two people involved in the talks who declined to be identified before an official announcement.

Yuji Orihara, the unit's president, declined to comment. Mary Klem, a spokeswoman for Thousand Oaks, California-based Amgen, wouldn't confirm or deny the sale.

``We are consulting with internal and external advisers as we consider the future of our operation in Japan,'' Klem said. ``All options are on the table.'' She declined to name the parties involved and said a sale was ``speculation.''

Amgen cut its 2007 earnings forecast at least three times this year after studies showed anemia drugs Epogen and Aranesp raised the risk of heart attack and death in high doses. Sales of Aranesp, the company's biggest product with $4.12 billion in sales in 2006, fell 23 percent in the third quarter. Amgen said in August it planned to cut as many as 2,600 jobs and slash capital spending by $1 billion.

Klem described Amgen K.K. as a development organization, with most staffers implementing, designing and overseeing clinical trials. It also has a licensing group, she said.

Biotech Drugs

Amgen develops products including biotechnology-based treatments for diseases including cancer, rheumatoid arthritis and asthma in Japan.

Amgen products are mostly marketed through Kirin Holdings Co., Japan's biggest brewer. Tokyo-based Kirin and Amgen established a joint venture in the U.S. in 1984 to make Epogen, or erythropoietin, together.

Daiichi Sankyo Co., Japan's third-largest drugmaker bought Japanese rights to develop and sell the experimental cancer therapy denosumab from Amgen in July. A medicine for hepatitis C is being developed for Japan with Astellas Pharma Inc., the second-largest drugmaker in Japan.

To contact the reporter on this story: Kanoko Matsuyama in Tokyo at at kmatsuyama2@bloomberg.netHideki Sagiike in Tokyo at at hsagiike@bloomberg.net

Last Updated: December 10, 2007 23:20 EST