T-Cell Depleted Double UCB for Refractory AML

This single center study will determine the feasibility and safety of using a myeloablative
conditioning regimen followed (on day 0) by transplantation with double T-cell depleted (TCD)
umbilical cord blood (UCB) units where the unit with fewer mononuclear cells (MNCs)/kg will
be selected for overnight IL-2 activation prior to infusion. Beginning on day +3, post
transplant IL-2 will be administered thrice weekly, not on consecutive days, for a total of 6
doses to expand UCB derived progenitor cells. Post transplant immune suppression prophylaxis
will not be administered with the intent to lessen toxicity and allow allogeneic NK cells to
function longer providing better anti-leukemic therapy. However if either UCB unit has more
than 5% T-cells, the patient will not receive either course of IL-2. Beginning on day +60
after transplantation, a second course of IL-2 will be administered thrice weekly, not on
consecutive days, for a total of 6 doses with the purpose of enhancing the in vivo expansion
and education of NK cells derived from engrafting UCB cells.

Inclusion Criteria:

- Aged 2 to 45 years with acute myeloid leukemia (AML) who meet one of the following
criteria:

- Primary induction failure defined as no complete remission (CR) after two or
three induction cycles (no blast limit).

- Relapsed AML with low disease burden: For patients >21 through 45 years of age:
must have <30% marrow blasts within 14 days of enrollment and be at least 28 days
from the start of last therapy. For patients 2 through ≤ 21 years of age: must
have >5% marrow blasts after no more than 3 induction attempts.

Patients with prior central nervous system (CNS) involvement are eligible provided that it
has been treated and is in remission. CNS therapy (chemotherapy or radiation) should
continue as medically indicated during the protocol.

- Have acceptable organ function within 14 days of study registration defined as:

- Renal: creatinine ≤ 2.0 mg/dL (adult patients) or calculated creatinine clearance
> 40 ml/min (pediatric patients)

- Hepatic: bilirubin, aspartate aminotransferase (AST), alanine aminotransferase
(ALT), alkaline phosphatase (ALP) ≤ 5 times upper limit of normal

- Pulmonary function: diffusing lung capacity for carbon monoxide corrected for
hemoglobin (DLCOcorr) > 50% of normal, (oxygen saturation [>92%] can be used in
child where pulmonary function tests (PFT's) cannot be obtained)

- Cardiac: left ventricular ejection fraction ≥ 45%

- Karnofsky Performance Status ≥ 70% (≥ 16 years) or Lansky Play Score ≥ 50 (pediatrics
< 16 years)

- Women of childbearing potential must agree to use adequate contraception (diaphragm,
birth control pills, injections, intrauterine device [IUD], surgical sterilization,
subcutaneous implants, or abstinence, etc.) for the duration of treatment.

- All patients will be questioned about prior exposure to antibody therapy (including
OKT3, rituximab, trastuzumab, and gemtuzumab) without affect to eligibility. Patients
with prior exposure will have a blood sample collected for human antimouse antibody
(HAMA). For patients with no prior antibody therapy exposure, no further action will
be taken.

- Voluntary written consent

Exclusion Criteria:

- Active infection at time of enrollment or documented fungal infection within 3 months
unless clearance from Infectious Disease

- Evidence of HIV infection or known HIV positive serology

- Pregnant or breast feeding.

- If < or = 21 years old, prior myeloablative transplant within the last 6 months. If >
21 years old prior myeloablative allotransplant or autologous transplant - if prior
conditioning regimen included total body irradiation (TBI), then
busulfan/cyclophosphamide(BU/CY) prep should be used

- If > 21 years old - extensive prior therapy including > 12 months of any alkylator
chemotherapy (etoposide >100 mg/m^2 x 5 days, cyclophosphamide >1 gm/m^2 or
mitoxantrone >8 gm/m^2) delivered at 3-4 week intervals or > 6 months alkylator
therapy (as above) with extensive radiation (determined by Radiation Oncology, e.g.
mantle irradiation for Hodgkin's) and/or prior radiation therapy that makes a patient
ineligible for TBI.

- Known hypersensitivity to any of the study agents