Rigel Pharmaceuticals, Inc. operates as a clinical stage biotechnology company. It discovers and develops novel, targeted drugs in the therapeutic areas of immunology, oncology and immune oncology. The firm focuses on intracellular signalling pathways and related targets that are critical to disease mechanisms. Its products include Tavalisse, Fostamatinib and R835. The company was founded by Donald G. Payan, James M. Gower, Thomas A. Raffin, Garry P. Nolan and Ronald B. Garren on June 14, 1996 and is headquartered in South San Francisco, CA.