Inclusion Criteria:

1. 1. Patients with refractory or relapsed acute myelogenous leukemia, or
myelodysplastic syndromes (RAEB or RAEB-T).

2. 2. Performance status of =< 2

3. 3. Signed informed consent indicating that patients are aware of the investigational
nature of this study in keeping with the policies of the hospital. The only
acceptable consent form is the one attached at the end of this protocol for each
participating institution.

4. 4. Patients must have been off chemotherapy for 2 weeks prior to entering this study
and recovered from the toxic effects of that therapy, unless there is evidence of
rapidly progressive disease.

5. 5. Bilirubin and creatinine (or creatinine clearance) should be within institutional
normal limits.

6. 6. Patients must have relapsed or failed to respond after high-dose ara-C-based
(>=1g/m2/day x 3 days) chemotherapy.

7. 7. Corrected DLCO >50%.

8. 8. Patients with >=3 cardiac risk factors (smoking, hypertension, family history of
coronary artery disease, diabetes mellitus, hypercholesterolemia) should have a
nuclear medicine stress test.

Exclusion Criteria:

1. 1. The anti-proliferative activity of the experimental drug may be harmful to the
developing fetus or nursing infant. Therefore, pregnant and nursing females will be
excluded. Patients of childbearing potential should practice effective methods of
contraception.

2. 2. Patients who are eligible for allogeneic marrow transplant and who have a donor
will be offered transplant.

3. 3. Patients with existing pulmonary diseases, history of coronary artery disease or
who have received radiotherapy to the mediastinum.