Bridging Study to Eliminate Presence of MRD for Acute Leukemia Before HCT

Inclusion Criteria:

* Diagnosis of acute lymphoblastic leukemia (ALL) or acute myeloid leukemia (AML) with \< 5% blasts in the bone marrow (M1) by morphology and that meets one of the following criteria:

Flow cytometric evidence of MRD (≥ 0.01% leukemic blasts for ALL or ≥ 0.5% leukemic blasts for AML detected in the bone marrow) OR Molecular/cytogenetic evidence of disease (FISH or PCR methodology) performed within 7 days And with the intent of going on to an allogeneic hematopoietic cell transplantation (HCT) independent of this study

* Patients must have an available donor and have intention of proceeding directly to ALL-HCT after completion of 1 cycle of Bridging therapy.
* Age 0 to 39 years
* Karnofsky Performance Status ≥ 50% for patients 16 years and older and Lansky Play Score ≥ 50 for patients under 16 years of age (see Appendix 2)
* Patients must have a life expectancy ≥ 8 weeks as determined by the enrolling investigator
* Have acceptable organ function as defined within 7 days of study registration

Renal: creatinine clearance ≥ 60 mL/min/1.73 m2 or serum creatinine based on age/gender as follows:

Hepatic: ALT \< 5 x upper limit of normal (ULN) and total bilirubin ≤ 1.5 x upper limit of normal (ULN) for age Cardiac: left ventricular ejection fraction ≥ 40% by ECHO/MUGA

* Patients must have fully recovered from the acute toxic effects of all prior chemotherapy, immunotherapy, or radiotherapy prior to entering this study. At least 7 days must have elapsed from prior chemotherapy.
* Hematopoietic Growth Factors: At least 7 days since the completion of therapy with a growth factor and at least 14 days since pegfilgrastim (Neulasta®) administration.
* Sexually active females of child bearing 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 and for 2 months after the last dose of chemotherapy. Sexually active men must agree to use barrier contraceptive for the duration of treatment and for 2 months after the last dose of chemotherapy.
* Voluntary written consent before performance of any study-related procedure not part of normal medical care, with the understanding that consent may be withdrawn by the subject at any time without prejudice to future medical care.

Exclusion Criteria:

* Acute Promyelocytic Leukemia (APL)
* Active extramedullary disease (CNS ≥ CNS2 and/or testicular leukemia) or presence of chloromatous disease
* Receiving concomitant chemotherapy, radiation therapy; immunotherapy or other anti-cancer therapy other than is specified in the protocol
* Systemic fungal, bacterial, viral, or other infection not controlled (defined as exhibiting ongoing signs/symptoms related to the infection and without improvement, despite appropriate antibiotics or other treatment)
* Pregnant or lactating. The agents used in this study are known to be teratogenic to a fetus and there is no information on the excretion of agents into breast milk. All females of childbearing potential must have a blood test or urine study within 2 weeks prior to registration to rule out pregnancy.
* Known allergy to any of the agents or their ingredients used in this study
* Participating in a concomitant Phase 1 or 2 study