Inclusion Criteria:

- Histologically confirmed diagnosis of 1 of the following hematologic malignancies:

- Relapsed or refractory acute myeloid leukemia (AML)

- Relapsed or refractory acute lymphoblastic leukemia

- Secondary AML, including AML arising from antecedent hematologic diseases, such
as myelodysplastic syndromes or myeloproliferative disorders OR therapy-related
AML

- Chronic myeloid leukemia in accelerated or blast phase

- Refractory to standard therapy or no standard therapy exists

- No known brain metastases

- Performance status - CALGB 0-2

- Performance status - Karnofsky 60-100%

- No G6PD deficiency

- Bilirubin < 2.0 mg/dL (unless due to Gilbert's syndrome)

- AST and ALT < 2.5 times upper limit of normal (ULN)

- Creatinine < 1.5 times ULN

- No symptomatic congestive heart failure

- No unstable angina pectoris

- No cardiac arrhythmia

- No pulmonary disease requiring oxygen

- Not pregnant or nursing

- Negative pregnancy test

- Fertile patients must use effective contraception

- No prior allergic reactions attributed to compounds of similar chemical or biological
composition to study drugs

- No neuropathy

- No ongoing or active infection

- No psychiatric illness or social situation that would preclude study compliance

- No other concurrent uncontrolled illness

- No concurrent biologic agents

- At least 72 hours since prior hydroxyurea

- At least 2 weeks since other prior chemotherapy (6 weeks for mitomycin or
nitrosoureas)

- No other concurrent chemotherapy

- At least 2 weeks since prior radiotherapy

- No concurrent radiotherapy

- Recovered from all prior therapy

- At least 4 weeks since prior investigational agents

- No other concurrent investigational therapy

- No other concurrent anticancer therapy

- No concurrent combination antiretroviral therapy for HIV-positive patients