Inclusion Criteria

- INCLUSION CRITERIA:

MDS of RA, RARS & RAEB sub-types

Off all other treatments (except G-CSF, and transfusion support and related medications)
for at least four weeks.

G-CSF can be used before, during and after the protocol treatment for patients with
documented neutropenia (less than 500/uL) as long as they meet the criteria for anemia
and/or thrombocytopenia as stated above.

ECOG performance status of 2 or less

High or intermediate predcted probability of response

EXCLUSION CRITERIA:

MDS of FAB sub-group chronic myelomonocytic leukemia (CMML)

Transformation to acute leukemia (FAB sub-group RAEB-T, ie., greater than 20% blasts in
marrow aspirate)

Hypoplastic marrow without one major or two minor criteria

Treatment with growth factors (except for G-SCF) or cyclosporine within 4 weeks prior to
entry to protocol

ECOG performance status of greater than 2

Active uncontrolled infection

Current pregnancy, or unwilling to take oral contraceptives if of childbearing potential

Patients for whom bone marrow transplant is indicated as standard therapy (age less than
fifty-five with a fully-matched sibling donor)

Age less than18 years

Not able to give informed consent

HIV positive patients

Active malignant disease (excluding basal cell carcinoma)

Serum creatinine greater than 2mg/dl

Patients who are moribund or patients with concurrent hepatic, renal, cardiac, metabolic,
or any disease of such severity that death within 3 months is likely

Low predicted probability of response