Inclusion Criteria

DISEASE CHARACTERISTICS:

- Diagnosis of 1 of the following:

- All chronic myelomonocytic leukemia (CMML)-2 patients

- CMML-1 patients meeting any of the following criteria:

- Symptomatic bone marrow failure/myeloproliferation defined as any of the
following:

- Red cell transfusion dependence and pre-transfusion hemoglobin < 9.0
g/dL

- Symptomatic anemia (hemoglobin < 11.5 g/dL)

- Thrombocytopenia (platelet count < 50 x 10^9/L)

- Symptomatic bleeding due to platelet functional defect or disseminated
intravascular coagulation (DIC)/fibrinolysis

- White cell count (WCC) > 50 x 10^9/L

- Düsseldorf Score of intermediate or high risk for proliferative CMML-1
(i.e., WCC > 12 x 10^9/L)

- International Prognostic Scoring System (IPSS) score of intermediate-2 or
high risk for non-proliferative CMML-1 (i.e., WCC < 12 x 10^9/L)

- Systemic symptoms including weight loss with no alternative explanation
(10% of baseline weight within the past 6 months)

- Symptomatic splenomegaly

- Symptomatic extramedullary involvement (e.g. skin infiltration or serous
effusions)

- No CMML with eosinophilia and 5q33 abnormality

PATIENT CHARACTERISTICS:

- WHO performance status 0-2

- Creatinine ≤ 2 times upper limit of normal

- Not pregnant or nursing

- Negative urine pregnancy test

- Fertile patients must use at least 2 forms of effective contraception during study
and for 3 months after completion of study therapy

- No other active malignant disease including basal cell or squamous cell carcinoma of
the skin

- No known HIV or infectious hepatitis B or hepatitis C

- No active infection

- No known hypersensitivity to azacitidine or mannitol

PRIOR CONCURRENT THERAPY:

- At least 28 days since other prior experimental drug or therapy

- No prior chemotherapy for this disease except hydroxycarbamide

- No other concurrent anticancer or investigational agents