JAK3 and rheumatoid arthritis: Decernotinib (IUPAC name: (2R)-2-methyl-2-[[2-(1H-pyrrolo[2,3-b]pyridin-3-yl)pyrimidin-4-yl]amino]-N-(2,2,2-trifluoroethyl)butanamide) is an oral selective JAK3 inhibitor whose development for the treatment of RA is presumed to have been discontinued.