Aurora B x Aurora A x FLT3 x Bcr-Abl T315I x JAK2

RATIONALE: AT9283 may stop the growth of cancer cells by blocking some of the enzymes needed for cell growth.
PURPOSE: This phase I/IIa clinical trial is studying the side effects and best dose of AT9283 in treating young patients with relapsed or refractory acute leukemia.

The purpose of this study is to find out whether the new drug AT9283 will slow the growth of multiple myeloma. Side effects of AT9283 will also be closely monitored.

The goal of this clinical research study is to find the highest tolerable dose of AT9283 that can be given to patients who have ALL, AML, CML, high-risk myelodysplastic syndromes, or myelofibrosis with myeloid metaplasia. Researchers want to perform pharmacokinetic (PK) testing on blood to find out how quickly the study drug leaves the body and how the body breaks down the drug. The safety and effectiveness of this drug will also be studied.