ImClone seen set to be acquired by Eli Lilly

BOSTON (Reuters) - ImClone Systems IMCL.O has agreed to be acquired by Eli Lilly (LLY.N) for about $6.1 billion (3.5 billion pounds) after rebuffing a sweetened takeover offer from Bristol-Myers Squibb (BMY.N), sources familiar with the situation said on Monday.

The agreement, which values ImClone at $70 per share, has been approved by the boards of both ImClone and Eli Lilly, sources said.

ImClone and Eli Lilly could not be immediately reached for comment.

Last week, Eli Lilly made a formal offer to buy ImClone, which makes the cancer drug Erbitux, for $70 a share, topping Bristol-Myers's offer of $62 per share for the 83 percent of ImClone it does not already own,

After rejecting Bristol-Myers, ImClone's Chairman Carl Icahn had stoked interest about a new suitor and said a "mystery bidder" was in talks to acquire ImClone.

ImClone said last week negotiations with the "mystery bidder" were continuing but the name of the suitor was not revealed. Reuters and other media outlets reported Eli Lilly as the "mystery bidder."

The negotiations with Eli Lilly led to a formal merger agreement, which includes a so-called "no shop" provision that prevents ImClone from actively soliciting superior offers, sources said.

Cancer is one of the three main areas of research focus at Eli Lilly, along with diabetes and neuroscience. Eli Lilly's has a robust oncology business, but its largest product, Gemzar, loses patent protection in 2012.

Like other major pharmaceutical companies facing competition from generic drug rivals, Eli Lilly also faces the risk of slower growth due to the pending patent expiry of its schizophrenia drug, Zyprexa.