Complex sentence: Ipilimumab (also known as MDX-010) is a human monoclonal antibody being developed by Bristol-Myers Squibb and Medarex which is used as a drug to activate the immune system.
Split into simpler sentences: Ipilimumab (also known as MDX-010) is a human monoclonal antibody being developed by Bristol-Myers Squibb and Medarex. It is intended to be used as a drug to activate the immune system.