Rigel Pharmaceuticals, Inc., a biotechnology company, engages in the discovery and development of small molecule drugs for the treatment of immune and hematologic disorders, cancer, and rare diseases. The company's clinical programs include Tavalisse, an oral spleen tyrosine kinase inhibitor for the treatment of adult patients with chronic immune thrombocytopenia; and Phase III clinical study for autoimmune hemolytic anemia. Its clinical programs also comprise R835, a proprietary molecule from its interleukin receptor associated kinase (IRAK) program, which is in Phase I clinical study for autoimmune and inflammatory diseases. The company has research and license agreements with Aclaris Therapeutics International Limited for the development and commercialization of janus kinase (JAK) inhibitors for the treatment of alopecia areata and other dermatological conditions; AstraZeneca AB for the development and commercialization of R256, an inhaled JAK inhibitor; BerGenBio AS for the develop