Multi-center Study of Myeloablative Allo Stem Cell Transplant for Non-remission AML Using CloBu4 Regimen

Inclusion Criteria: Disease Criteria * AML not in remission at the time of transplant * "Not in remission" is defined as "greater than 5.0% bone marrow blasts by aspirate morphology," as determined by a bone marrow aspirate obtained within 2 weeks of study registration. * For primary induction failure patients: Patients must have failed at least 2 induction regimens. * For patients with relapsed disease: Patients who relapse more than 6 months after preceding remission must fail at least one reinduction regimen to be eligible. For patients in whom the preceding remission is equal to or shorter than 6 months duration, no re-induction regimen is required to qualify for this protocol. * If the pre-transplant bone marrow aspirate and biopsy are hypoplastic (less than 10% cellularity), and blast percentages cannot be determined, the patient is eligible if the preceding bone marrow met the above criteria. * Patients with peripheral circulating blasts or patients with extramedullary leukemia are eligible if bone marrow aspirate and biopsy meets the above criteria. Age and Organ Function Criteria * Age: 2 to 65 years in age. * Cardiac: LVEF ≥ 40% by MUGA (Multi Gated Acquisition) scan or echocardiogram. * Pulmonary: FEV1 and FVC capacity) ≥ 40% predicted, DLCO (corrected for hemoglobin) ≥ 40% of predicted. * Children who are unable to cooperate for pulmonary function tests (PFTs), must have no evidence of dyspnea at rest, no exercise intolerance, and not require supplemental oxygen therapy. * Renal: Age equal to or older than 12: The estimated creatinine clearance (CrCl) must be equal or greater than 60 mL/min/1.73 m2 as calculated by the Cockcroft-Gault Formula. Age younger than 12: Either estimated or measured CrCl should be greater than 90 ml/min/1.73m2. For estimation, Schwartz formula will be used. * Hepatic: Serum bilirubin ≤ 1.5 x upper limit of normal (ULN); (AST)/ ALT ≤ 2.5 x ULN; Alkaline phosphatase ≤ 2.5 x ULN * Performance status: Karnofsky ≥ 70%., or Lansky≥70% Consent: All patients must sign informed consent Exclusion Criteria: * Active life-threatening cancer requiring treatment other than AML * Non-compliant to medications. * No appropriate caregivers identified. * HIV1 (Human Immunodeficiency Virus-1) or HIV2 positive * Active life-threatening cancer requiring treatment other than AML * Uncontrolled medical or psychiatric disorders. * Uncontrolled infections, defined as positive blood cultures within 72 hours of study entry, or evidence of progressive infection * Active central nervous system (CNS) leukemia * Preceding allogeneic HSCT * Receiving intensive chemotherapy within 21 days of registration. * Patients with preceding primary myelofibrosis * Peripheral blasts \> 10,000/μL at the time of registration