WP-1034 is a novel Jak-Stat inhibitor, which is active against AML blasts. WP-1034 effectively inhibited proliferation of OCIM2 cells and fresh AML samples. WP-1034 caused cell cycle arrest of OCIM2 cells in sub-Go phase. WP-1034 induced apoptosis of OCIM2 cells and that induction of apoptosis involved cleavage of caspase 3 and the DNA repair enzyme poly (adenosine diphosphate [ADP]-ribose) polymerase (PARP).