BMS and Medarex: Top 10 deals of 2009

Who: Bristol-Myers Squibb
With: Medarex
What: $2.4 billion buyout

Summary: Anxious to beef up its pipeline as it braces for Plavix to go off-patent, Bristol-Myers Squibb struck a deal in July to buy Medarex for $2.4 billion. The crown jewel of the deal was ipilimumab, a late-stage cancer therapy being advanced as a new treatment for metastatic melanoma. The monoclonal antibody also turned in impressive results for prostate cancer and is in testing for lung cancer as well.