NEW YORK (AP) -- Bristol-Myers Squibb Co. said Thursday it completed its initial tender offer for shares of Medarex Inc., a rival it agreed to buy for $2.1 billion.

Bristol-Myers said 87.7 percent of Medarex stock, or a total of 119 million shares, were tendered. The company is preparing for an additional tender offer in which it will try to buy the remaining shares. That period is expected to close by Monday.

According to Bristol-Myers, the sale will finish faster if more than 90 percent of Medarex shares are tendered. Even if that does not happen, the deal is expected to close by the end of 2009.

Bristol-Myers offered $16 per share for the Princeton, N.J., biotechnology company on July 22.