Rigel Pharmaceuticals, Inc., a clinical-stage drug development company, engages in the discovery and development of small molecule drugs for the treatment of inflammatory/autoimmune diseases and cancer, as well as viral and metabolic diseases. Its product candidates include R788, which is currently in three Phase II trials for rheumatoid arthritis, immune thrombocytopenic purpura, and lymphoma; and R763, which is in three Phase I trials, in collaboration with Merck Serono, for the treatment of oncology. The company has also partnered product development programs relating to asthma and cancer. Rigel Pharmaceuticals has done collaboration agreements with Merck Serono, S.A.; Pfizer, Inc.; Johnson & Johnson; Merck; Novartis Pharma AG; and Daiichi Pharmaceuticals Co., Ltd. The company was incorporated in 1996 and is based in South San Francisco, California.