Medarex

Medarex (former NASDAQ symbol: MEDX ) was an American biopharmaceutical company based in Princeton, New Jersey, with manufacturing facilities in Bloomsbury and Annandale, New Jersey, and research facilities in Milpitas and Sunnyvale, California. In 2009, Medarex was purchased by Bristol Myers Squibb.

Medarex developed monoclonal antibodies to CTLA-4 and PD-1, which are proteins on the surface of T cells. T cells attack cancer cells, but CTLA-4 and PD-1 act as "brakes" on the T cell's anti-cancer activities. The monoclonal antibodies bind to these proteins and block them, releasing the T cell to attack cancer cells.

Several monoclonal antibodies developed by Medarex have been approved for disease therapy. In 2009, the U.S. Food and Drug Administration approved Simponi, a human monoclonal antibody to tumor necrosis factor alpha co-developed with Johnson & Johnson's Janssen Biotech, for treatment of arthritis. In 2011, the U.S. FDA approved ipilimumab, a monoclonal antibody to CTLA-4, for treatment of metastatic melanoma. In 2014, the U.S. FDA approved nivolumab, a monoclonal antibody to PD-1, for treatment of advanced melanoma. Its use was expanded to the treatment of squamous non-small-cell lung carcinoma in 2015.

Medarex developed some of the first transgenic mice with humanized immune systems, in order to generate fully human antibodies. Many of the on-market monoclonal antibodies have been derived from this platform.