DISEASE CHARACTERISTICS:

• One of the following diagnoses:

  • High-risk myelodysplastic syndromes (MDS)

  • Acute myeloid leukemia (AML)

    • De novo, secondary, or relapsed disease
    • Any number of prior regimens for primary or relapsed disease
• Ineligible for or refuses aggressive management

• Measurable disease, defined as:

  • More than 5% blasts in bone marrow of patients with MDS
  • More than 30% blasts in bone marrow of patients with AML
• Involvement of cerebrospinal fluid allowed

PATIENT CHARACTERISTICS:

Age

• 18 and over

Performance status

• ECOG 0-2 OR
• Karnofsky 60-100%

Life expectancy

• Not specified

Hematopoietic

• See Disease Characteristics

Hepatic

• Bilirubin no greater than 1.25 times upper limit of normal (ULN)
• AST and/or ALT no greater than 1.25 times ULN

Renal

• Creatinine less than 1.7 mg/dL OR
• Creatinine clearance at least 60 mL/min

Cardiovascular

• No symptomatic congestive heart failure
• No unstable angina pectoris
• No cardiac arrhythmia

Other

• No ongoing or active infection
• No other uncontrolled illness that would preclude study participation
• No psychiatric illness or social situation that would preclude study compliance
• No prior allergic reactions to compounds of similar chemical or biological composition to decitabine
• No other active malignancy
• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception

PRIOR CONCURRENT THERAPY:

Biologic therapy

• At least 4 weeks since prior biologic therapy (e.g., interferon, filgrastim [G-CSF], sargramostim [GM-CSF], thrombopoietin, or epoetin alfa)
• No concurrent hematopoietic growth factors (GM-CSF, thrombopoietin, or epoetin alfa)
• No concurrent prophylactic G-CSF

Chemotherapy

• Prior intrathecal cytarabine allowed for patients with cerebrospinal fluid involvement
• At least 4 weeks since prior chemotherapy (except low-dose chemotherapy administered to maintain WBC counts) (6 weeks for nitrosoureas or mitomycin) and recovered
• At least 24 hours since prior hydroxyurea
• Concurrent intrathecal cytarabine allowed for patients with cerebrospinal fluid involvement

Endocrine therapy

• Not specified

Radiotherapy

• No prior radiotherapy greater than 3,000 cGy to marrow-producing areas
• At least 4 weeks since prior radiotherapy and recovered

Surgery

• Not specified

Other

• Prior investigational therapy allowed
• No other concurrent investigational agents
• No concurrent combination antiretroviral therapy for HIV-positive patients
• No other concurrent anticancer therapy