ATP-competitive inhibitor of Aurora kinases A and B (IC50 values are 0.8 and 5 nM for recombinant Aurora B and Aurora A, respectively). Inhibits phosphorylation of Aurora B, histone H3 and Aurora A in cultured MDA-MB-231 cells (IC50 values are approximately 20, 50 and 150 nM respectively). Shown to block cytokinesis; inhibits cellular proliferation in several human tumor cell lines, including HCT-116, HL-60, A549 and H125, and in human xenograft mouse models. Orally available. Purity 98%. MW (observed): 474.48