Rigel Pharmaceuticals Inc develops small-molecule drugs for autoimmune, cancer-related, and viral diseases. The firm's lead drug is an oral rheumatoid arthritis drug candidate that has been licensed to AstraZeneca. Astra has taken overall responsibility for developing and marketing the drug and will pay Rigel royalties and milestone payments. Its pipeline product includes TAVALISSE (fostamatinib disodium hexahydrate) tablets, the only oral spleen tyrosine kinase (SYK) inhibitor, Fostamatinib, R289, R552, R835, DS-3032, THF-beta Inhibitors, and AZD0449- Inhaled JAK Inhibitor.