Cenisertib (also known as R763) is water-soluble, synthetic small molecule aurora kinase inhibitor with potential antineoplastic activity. Cenisertib is a potent adenine triphosphate-competitive inhibitor of Aurora kinase isoforms A–C, disrupting mitotic spindle activity, blocking cell separation, and leading to polyploidy and cell death. At low nanomolar concentrations, Cenisertib also inhibits other kinases involved in cell survival and proliferation including FLT3, BCR-ABL1, and BCR-ABL1 with T315I mutation. It also inhibits JAK2 kinase, but at higher concentrations. Preclinically, Cenisertib has demonstrated potent antitumor activity as a single agent and in combination treatment in leukemia cell lines, freshly isolated leukemia cells, and leukemia xenograft models. Toxicities appear to be related mainly to the gastrointestinal and hematopoietic systems. In animal models, activity and toxicity depend not only on dose but also on the schedule of administration.