Allogeneic HCT Using Nonmyeloablative Host Conditioning With TLI & ATG vs SOC in AML

INCLUSION CRITERIA * ≥ 50 years of age and ≤ 75 years of age. * De novo acute myelogenous leukemia (AML), based on FAB and WHO criteria. * Intermediate or unfavorable cytogenetic abnormalities based on Southwest Oncology Group (SWOG) Cytogenetic Criteria. * First morphologic complete remission (CR), or CRp (a complete remission but with low platelets) following 1 or 2 courses of induction therapy, documented no more than 8 weeks prior to the date of enrollment and confirmed at time of enrollment. * Karnofsky Performance Score ≥ 60. * Suitable for non-myeloablative transplantation or best treatment. * Able to understand and willing to sign a written informed consent document. EXCLUSION CRITERIA * AML with favorable cytogenetic features based on SWOG Cytogenetic Criteria * AML, either treatment-related or MDS-related * Active CNS disease as identified by positive CSF cytospin at time of enrollment. * Prior or concurrent malignancies except localized non-melanoma skin malignancies or treated cervical carcinoma in situ. (EXCEPTION: Cancer treated with curative intent \> 5 years previously is allowed. EXCEPTION: Low grade lymphoma is allowed as long as active treatment is not required for control of disease) * Planned for allogeneic transplant using a full-dose conditioning * Life expectancy \< 1 year due to diseases other than malignancy * Pregnant or breastfeeding. * HIV-seropositive. * Uncontrolled infection (presumed or documented) with progression after appropriate therapy for greater than one month. * Symptomatic coronary artery disease or uncontrolled congestive heart failure. Left ventricular ejection fraction (LVEF) is not required to be measured, however if measured, exclusion if ejection fraction is \< 30%. * Requiring supplementary continuous oxygen. Diffusing capacity of the lungs for carbon monoxide (DLCO) is not required to be measured, however if it is measured, exclusion if DLCO \< 35%. * Fulminant liver failure * Cirrhosis with evidence of portal hypertension or bridging fibrosis * Alcoholic hepatitis * Esophageal varices * A history of bleeding esophageal varices * Hepatic encephalopathy * Uncorrectable hepatic synthetic dysfunction evidenced by prolongation of the prothrombin time * Ascites related to portal hypertension * Chronic viral hepatitis with total serum bilirubin \> 3 mg/dL * Symptomatic biliary disease