Bristol-Meyers last week offered to acquire the rest of ImClone it does not already own in a deal that values the company at $5.2 billion. ImClone said its board of directors has formed a committee to study the offer and to hire financial advisers.

ImClone said its board has been discussing the possibility of separating the company into its Erbitux cancer drug and its drug-development pipeline businesses. The company said it believes the pipeline business "may be extremely valuable and significantly increase stockholder value as a separate business."

Activist investor Carl Icahn, who also is chairman of ImClone's board and a large shareholder of the biotech company, told the company's board he is opposed to Bristol-Myers' offer because he believes it "greatly undervalues the company."

(Reporting by Jessica Hall)

(For more M&A news and our DealZone blog, go to http://www.reuters.com/investing/news/mergers)