Inclusion Criteria:

- Age 18 - 75 years

- Histologically or cytologically documented relapse of acute myeloid leukemia after a
stem cell transplant

- Must have a minimum of 10% donor cells by chimerism assays (RFLP or FISH) prior to
enrollment

- Patients must be at least 2 weeks from cessation of immunosuppression.

- Donors must be no more than two HLA antigen (HLA A, B, C, DR) mismatched with the
transplant recipient by high resolution molecular HLA typing.

- ECOG performance status 0-2, Lansky performance status >70 (see Appendix 1).

- Female patients of childbearing potential must have a negative serum pregnancy test
within 7 days of enrollment.

- Male and female patients must agree to use a medically acceptable barrier and/or
chemical contraceptive method during the study and for a minimum of 3 months after
the last dose of chemotherapy on this study.

Exclusion Criteria:

- Active CNS leukemia. Prior CNS leukemia allowed provided current CSF cytology is
normal.

- Current concomitant chemotherapy, radiation therapy, or immunotherapy. Must be off
therapy for at least 2 weeks prior to enrollment with the following exceptions:

- Hydroxyurea: at least 72 hours

- Biologic agents (e.g., Imatinib, dasatinib, etc.): at least 7 days

- Hematopoietic growth factors (e.g., filgrastim, pegfilgrastim, etc.): at least 7 days

- Persistent clinically significant toxicity from prior anticancer therapy that is >
Grade 2 (NCI CTCAE v3.0).

- Bilirubin > 2 mg/dL, and SGOT/SGPT >2.5 x normal.

- Ejection fraction by echocardiogram < 50%

- Absolute neutrophil count < 500, platelet count < 25,000

- Creatinine clearance < 50ml/min as estimated by patient's serum creatinine, weight,
and age.

- Room air pulse oximetry < 94%.

- Bone marrow or stem cell transplant within 2 months prior to treatment on protocol

- Pregnant or lactating females are excluded.

- Other active systemic malignancy other than leukemia expected to require therapy
within 4 months.

- Patients with a systemic fungal, bacterial, viral, or other infection not controlled