Bristol-Myers Squibb has proposed to acquire the stake in ImClone it does not already own for $60 per share in cash, in a deal valued at about $4.5 billion.

Currently, Bristol-Myers Squibb owns about 17 percent of ImClone's outstanding shares, and the offer represents a 30-percent premium on ImClone's stock on July 30. The companies have been partnered on the development and marketing for cancer drug Erbitux in the US and Canada since 2001.

"For Bristol-Myers Squibb, the proposed acquisition of ImClone represents a strategically and financially sound add-on to our business, consolidating a relationship we have had for nearly seven years. The acquisition is expected to contribute to our financial performance in the 2012-2013 timeframe as well as drive growth beyond 2013,” commented Bristol-Myers Squibb's CEO James Cornelius.