90Y-DOTA-anti-CD25 Basiliximab, Fludarabine, Melphalan, and Total Marrow and Lymphoid Irradiation for the Treatment of High-Risk Acute Leukemia or Myelodysplastic Syndrome

Inclusion Criteria:

• Documented informed consent of the participant and/or legally authorizedrepresentative

• Assent, when appropriate, will be obtained per institutional guidelines

• Age: >= 60 years. Note: Patients >= 18 years and < 60 years are also included ifthey are not candidates for myeloablative conditioning regimens due to comorbidities

• Karnofsky performance status >= 70

• Eligible patients will have a histopathological confirmed diagnosis of hematologicmalignancy in one of the following categories which express CD25 as determined byimmunohistochemistry:

• Acute myelogenous leukemia:

• Patients with de novo or secondary disease in unfavorable risk groupincluding poor risk cytogenetics according to National ComprehensiveCancer Network (NCCN) guidelines for acute myeloid leukemia (AML) i.e.,monosomal karyotype, -5,5q-,-7,7q-, 11q23-non t(9;11), inv (3), t(3;3),t(6;9), t(9;22) and complex karyotypes (>= 3 unrelated abnormalities), orall patient in intermediate risk groups accept patients with FLT3-NPM1+disease

• Patients with a complete morphological remission (CR) with minimalresidual disease (MRD)-positive status by flow cytometry or cytogenetic

• Patients with chemosensitive active disease

• Acute lymphocytic leukemia:

• Patients with de novo or secondary disease according to NCCN guidelinesfor acute lymphocytic leukemia (ALL) hypoploidy (< 44 chromosomes);t(v;11q23): MLL rearranged; t(9;22) (q34;q11.2); complex cytogenetics (5or more chromosomal abnormalities); high white blood cell (WBC) atdiagnosis (>= 30,000 for B lineage or >=50,000 for T lineage); iAMP21lossof 13q, and abnormal 17p

• Patients with a complete morphological remission (CR) with MRD-positivestatus by flow cytometry or cytogenetics

• Patients with chemosensitive active disease

• Myelodysplastic syndrome in high-intermediate (int-2) and high-risk categories

• A pretreatment measured creatinine clearance (absolute value) of >= 60 ml/minute (performed within 30 days prior to day 1 of protocol therapy unless otherwisestated)

• Patients must have a serum bilirubin =< 2.0 mg/dl (performed within 30 days prior today 1 of protocol therapy unless otherwise stated)

• Serum glutamic-oxaloacetic transaminase (SGOT) and serum glutamate pyruvatetransaminase (SGPT) =< 2.5 times the institutional upper limits of normal (performedwithin 30 days prior to day 1 of protocol therapy unless otherwise stated)

• Ejection fraction measured by echocardiogram or multigated acquisition scan (MUGA) >= 50% (performed within 30 days prior to day 1 of protocol therapy unless otherwisestated)

• Diffusion capacity of the lung for carbon monoxide (DLCO) and forced expiratoryvolume in 1 second (FEV1) > 50% predicted (performed within 30 days prior to day 1of protocol therapy unless otherwise stated)

• Agreement by females and males of childbearing potential to use an effective methodof birth control or abstain from heterosexual activity for the course of the studythrough at least 6 months after the last dose of protocol therapy

• Childbearing potential defined as not being surgically sterilized (men andwomen) or have not been free from menses for > 1 year (women only)

Exclusion Criteria:

• Autologous or allogeneic hematopoietic cell transplant

• Patients may not have received more than 3 prior regimens, where the regimen intentwas to induce remission

• Receiving any other investigational agents or concurrent biological, intensivechemotherapy or radiation therapy for the previous 2 weeks from conditioning. Note:Receiving any other investigational agents or concurrent biological, intensivechemotherapy or radiation therapy for the previous 2 weeks from conditioning

• Patients should have discontinued all previous intensive therapy, chemotherapy, orradiotherapy for 2 weeks prior to commencing therapy on this study. Note: Low dosechemotherapy or maintenance chemotherapy given within 7 days of planned studyenrollment is permitted. These include hydroxyurea, 6-meraptopurine, oralmethotrexate, vincristine, oral etoposide, and tyrosine kinase inhibitors (TKIs).FLT-3 inhibitors can also be given up to 3 days before conditioning regimen

• All patients with prior radiation treatment to the lung, liver, and kidney will beexcluded. For other scenarios of prior radiation treatment, up to 2000 cGy at 2 Gyper day will be allowed. Inclusion of patients with previous radiation exposure willbe determined based on the radiation oncologist medical doctor (MD) evaluation andjudgment

• History of allergic reactions attributed to compounds of similar chemical orbiologic composition to study agent

• Patients with other active malignancies are ineligible for this study, other thannon-melanoma skin cancers

• Patients should not have any uncontrolled illness including ongoing or activebacterial, viral or fungal infection

• The recipient has a medical problem or neurologic/psychiatric dysfunction whichwould impair his/her ability to be compliant with the medical regimen and totolerate transplantation or would prolong hematologic recovery which in the opinionof the principal investigator would place the recipient at unacceptable risk

• Females only: Pregnant or breastfeeding

• Any other condition that would, in the investigator's judgment, contraindicate thepatient's participation in the clinical study due to safety concerns with clinicalstudy procedures

• Prospective participants who, in the opinion of the investigator, may not be able tocomply with all study procedures (including compliance issues related tofeasibility/logistics)

• DONOR: Evidence of active infection

• DONOR: Medical or physical reason which makes the donor unlikely to tolerate orcooperate with growth factor therapy and leukapheresis

• DONOR: Factors which place the donor at increased risk for complications fromleukapheresis or granulocyte-colony stimulating factor (G-CSF) therapy could beharvested for bone marrow (BM) if safer for the donor and if approved by principalinvestigator (PI)

• DONOR: Human immunodeficiency virus (HIV) positive