Potent JAK3 inhibitor (IC50 = 8 nM). Selective for JAK3 over JAK1, JAK2 and TYK2 (IC50 values are 1017, 2550 and 8055 nM respectively). Also inhibits GSK-3β, PKCα and PKCθ (IC50 values are 3, 13 and 68 nM respectively).