AT9283 in Treating Young Patients With Relapsed or Refractory Acute Leukemia

DISEASE CHARACTERISTICS: * Histologically confirmed acute leukemia according to the following criteria: * Acute lymphoblastic leukemia (ALL) meeting any of the following criteria: * Second relapse * Refractory to induction therapy for first relapse * Third or subsequent relapse * Acute myeloid leukemia (AML) meeting any of the following criteria: * Second or subsequent relapse * Refractory to an induction therapy for first relapse * Without a curative treatment option * Other type of acute leukemia meeting any of the following criteria: * First or subsequent relapse * Refractory to induction therapy * Not eligible for any therapy of higher curative potential * No chronic myeloid leukemia (CML) * Patients in relapse must have ≥ 5% blasts in the bone marrow * Patients with refractory disease following induction must have ≥ 20% blasts in the bone marrow * No evidence of CNS disease PATIENT CHARACTERISTICS: * Karnofsky performance status (PS) 50-100% OR Lansky PS 50-100% * Life expectancy ≥ 8 weeks * Serum bilirubin \< 1.5 times upper limit of normal (ULN) * ALT or AST \< 2.5 times ULN (5 times ULN if due to leukemic infiltration of the liver) * Creatinine clearance ≥ 60 mL/min * Not pregnant or nursing * Negative pregnancy test * Fertile female patients must use 2 of the following combined forms of contraception (oral, injected, or implanted hormonal contraception and condom OR intra-uterine device and condom OR diaphragm with spe…