Amgen acquires Abgenix

Amgen Inc., the world's biggest biotechnology company, said it agreed to buy Abgenix Inc. for $2.2 billion in cash, acquiring full ownership of a colon cancer drug they have been developing jointly.

Amgen will pay $22.50 for each share of Freemont, Calif.-based Abgenix, a biotechnology company that develops human therapeutic antibodies, the companies said yesterday. The amount represents a 54 percent premium over Abgenix's closing price yesterday.

The acquisition would be Amgen's biggest since it bought Immunex in 2002 for $8.8 billion, gaining the rheumatoid arthritis drug Enbrel. Last year the company bought Tularik Inc. for $1.2 billion, getting experimental treatments for cancer, obesity, and heart disease. Chief executive Kevin Sharer has been bolstering product development through acquisitions.

Last week Amgen said its board cleared a plan to buy back as much as $5 billion more of the company's stock. The buybacks would add to 48.4 million shares repurchased in the first nine months of this year for $3.2 billion, according to a quarterly report to the Securities and Exchange Commission.