Ipilimumab

Overview
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. Ipilimumab is undergoing clinical trials for the treatment of melanoma.

Ipilimumab is a fully human antibody that binds to CTLA-4 (cytotoxic T lymphocyte-associated antigen 4), a molecule on T-cells that is believed to play a critical role in regulating natural immune responses. The absence or presence of CTLA-4 can augment or suppress the immune system's T-cell response in fighting disease. Ipilimumab is designed to block the activity of CTLA-4, thereby sustaining an active immune response in its attack on cancer cells.

As of October 2007 there are two fully human anti CTLA-4 monoclonal antibodies in advanced clinical trials. Ipilimumab, which is an IgG1 isotype, and Tremelimumab (from Pfizer) which is an IgG2 isotype.