TAS05567 is a potent, highly selective, and ATP-competitive Syk inhibitor (IC50: 0.37 nM). TAS05567 only shows >70% inhibition of Syk and 4 other kinases (FLT3, JAK2, KDR, and RET with IC50s of 10 nM, 4.8 nM, 600 nM, and 29 nM, respectively) in a panel of 192 kinases.