S7036

XL019 is a highly selective JAK2 inhibitor, binds to the active site of JAK2 displaying >50-fold selectivity against JAK1 and TYK2. XL019 reveals a desirable CYP (1A2, 2C9, 2D6, 3A4 ≥20 μM), hERG (16 μM), and P-glycoprotein inhibition (>20 μM) profile. ^[1] XL019 inhibits the activation of JAK2 as well as the mutated form JAK2V617F, which may result in the inhibition of the JAK-STAT signaling pathway and may induce apoptosis. XL019 showed more than 10-fold selective inhibition (IC50 = 64 nM) of STAT5 phosphorylation following EPO stimulation of erythroid cells compared with other cell systems. ^[2]