Azacitidine in Treating Patients With Newly Diagnosed Previously Untreated or Secondary Acute Myeloid Leukemia Who Are Unsuitable For Intensive Chemotherapy

DISEASE CHARACTERISTICS: * Diagnosis of 1 of the following: * De novo acute myeloid leukemia (AML) * AML secondary to prior hematological disease or cytotoxic treatment * Newly diagnosed or untreated disease * At least 20% blasts in the blood or bone marrow or extramedullary disease * Must be considered unsuitable for intensive chemotherapy due to ≥ 1 of the following: * High age or frail for the biologic age * Relevant comorbidities * Unwilling to undergo intensive chemotherapy * No chronic myelogenous leukemia or acute promyelocytic leukemia PATIENT CHARACTERISTICS: * WHO performance status 0-3 * Bilirubin ≤ 3 times upper limit of normal (ULN) * Alkaline phosphatase ≤ 2.5 times ULN * AST ≤ 2.5 times ULN * Serum creatinine ≤ 2.5 times ULN * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective contraception during and for 12 months after completion of study treatment * Patient compliance and geographic proximity allow proper staging and follow-up * No NYHA class III-IV heart failure or relevant cardiac arrhythmia * No active hematological/oncological disease other than AML * No psychiatric disorder precluding understanding of information on trial related topics or giving informed consent * No serious underlying medical condition in the judgment of the investigator, which could impair the ability of the patient to participate in the trial, including but not limited to, any of the following: * Active autoimmune disease * Uncontrolled diabetes * Active uncontrolled infection * HIV infection * Active chronic hepatitis B or C infection * No known allergy or hypersensitivity to azacitidine or mannitol PRIOR CONCURRENT THERAPY: * No prior treatment for AML * No prior azacitidine or decitabine * No other concurrent experimental or investigational drugs or anticancer therapy * More than 30 days since participation in another clinical trial * No concurrent growth factors for use in afebrile and asymptomatic patients except to treat neutropenic infection