Rigel Pharmaceuticals, Inc., a clinical-stage drug development company, discovers and develops novel and small-molecule drugs for the treatment of inflammatory and autoimmune diseases, as well as muscle disorders. Its product development programs include Fostamatinib, an oral spleen tyrosine kinase (SYK) inhibitor, which is in Phase III clinical trials for the treatment of rheumatoid arthritis; R343, an inhaled SYK inhibitor that is in Phase II clinical trials to treat asthma; R333, a topical dermatological janus kinase (JAK)/SYK inhibitor, which is in Phase II clinical trials for the treatment of discoid lupus erythematosus; and R348, a topical ophthalmic JAK/SYK inhibitor that is in Phase I clinical trials to treat keratoconjunctivitis sicca. The company also conducts preclinical studies for an oral activator of adenosine monophosphate activated protein kinase to enhance the body's energy utilization and restore muscle endurance in chronically ill subjects. Rigel Pharmaceuticals, Inc. has collaboration agreements with AstraZeneca AB to develop and commercialize oral SYK inhibitors; and Daiichi Sankyo to conduct research related to drug targets called ligases that control cancer cell proliferation through protein degradation, as well as a license agreement with BerGenBio AS for the development and commercialization of an oncology program. The company was founded in 1996 and is based in South San Francisco, California.