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

The merger pact includes a so-called "no shop" provision that prevents ImClone from actively soliciting superior offers, sources said.

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

(Reporting by Toni Clarke; Writing by Jessica Hall; Editing by Kim Coghill)