Inclusion Criteria

DISEASE CHARACTERISTICS:

- Histologically confirmed myelodysplastic syndrome (MDS)

- Refractory anemia (RA)

- RA with excess blasts (RAEB)

- RAEB in transformation

- RA with ringed sideroblasts

- Non-proliferative chronic myelomonocytic leukemia (WBC less than 12,000/mm^3)

- At least 1 of the following cytopenias:

- Untransfused hemoglobin no greater than 10.0 g/dL and/or red cell transfusion
dependent

- Absolute neutrophil count no greater than 1,800/mm^3 (neutropenia)

- Platelet count no greater than 100,000/mm^3 (thrombocytopenia)

- No secondary MDS

- No known brain metastases

PATIENT CHARACTERISTICS:

Age:

- 18 and over

Performance status:

- ECOG 0-2

- Karnofsky 60-100%

Life expectancy:

- More than 4 months

Hematopoietic:

- See Disease Characteristics

- Platelet count at least 20,000/mm^3

- No hemorrhagic illness within the past 3 weeks

- No hemolysis

- No iron deficiency

- No active blood loss

Hepatic:

- AST and ALT no greater than 2.5 times upper limit of normal (ULN)

- Bilirubin no greater than 2.0 mg/dL

- INR less than 2.0

- PTT less than 1.5 times ULN

Renal:

- Creatinine no greater than 2.0 mg/dL

- No renal dysfunction requiring dialysis within the past 6 months

- No nephrotic syndrome within the past 6 months

Cardiovascular:

- No myocardial infraction within the past 6 months

- No severe or unstable angina within the past 6 months

- No severe peripheral vascular disease (ischemic rest pain, non-healing wound or
ulcer, or tissue loss) within the past 6 months

- No uncontrolled hypertension within the past 6 months

- No transient ischemic attack within the past 6 months

- No cerebrovascular accident within the past 6 months

- No deep venous or arterial thrombosis

- No coronary artery disease

- No symptomatic congestive heart failure (New York Heart Association class II-IV heart
disease)

- No cardiac arrhythmia

- No vascular illness within the past 3 weeks

Pulmonary:

- No pulmonary embolism

Other:

- Not pregnant or nursing

- Negative pregnancy test

- Fertile patients must use effective contraception

- No other active malignancy except localized squamous cell or basal cell skin cancer

- Prior cured malignancy allowed

- No trauma within the past 3 weeks

- No significant inflammatory disease within the past 3 weeks

- No serious non-healing wound, ulcer, or bone fracture

- No hypersensitivity to Chinese hamster ovary cell products or other recombinant human
or humanized antibodies

- No other active severe disease

- No infection

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

- HIV negative

PRIOR CONCURRENT THERAPY:

Biologic therapy:

- No prior allogeneic bone marrow transplantation

- At least 30 days since prior biologic response modifiers

- At least 30 days since prior hematopoietic growth factors

- At least 30 days since prior thalidomide

- No concurrent thalidomide

- No other concurrent biologic response modifiers

- No concurrent hematopoietic growth factors (including epoetin alfa)

- Concurrent filgrastim (G-CSF) for febrile neutropenia allowed

- Concurrent transfusions allowed

Chemotherapy:

- At least 30 days since prior chemotherapy

- No concurrent chemotherapy

Endocrine therapy:

- No concurrent corticosteroid therapy (more than 10 mg/day of prednisone or equivalent
steroid dose) except for pre-medication for transfusions

Radiotherapy:

- At least 30 days since prior radiotherapy

- No concurrent radiotherapy

Surgery:

- At least 3 weeks since prior surgery (including biopsy of visceral organ)

Other:

- At least 10 days since prior anticoagulants

- No concurrent cytotoxic agents

- No other concurrent investigational agents