Treosulfan, Fludarabine Phosphate, and Total-Body Irradiation Before Donor Stem Cell Transplant in Treating Patients With High-Risk Acute Myeloid Leukemia, Myelodysplastic Syndrome, Acute Lymphoblastic Leukemia

Inclusion Criteria:

* Acute myeloid leukemia (AML):

  * All AML patients beyond 1st remission;
  * Intermediate or high risk AML patients (based on South West Oncology Group \[SWOG\] cytogenetic criteria) in 1st complete remission
* Myelodysplastic syndrome (MDS)
* Other myeloid malignancies as chronic myelogenous leukemia (CML), CML accelerated phase, CML blast crisis, chronic myelomonocytic leukemia (CMML) (to be approved by patient care conference \[PCC\])
* With Karnofsky Index or Lansky Play-Performance Scale \> 70% on pre-transplant evaluation
* Able to give informed consent (if \> 18 years), or with a legal guardian capable of giving informed consent (if \< 18 years)
* Previous autologous or allogeneic HCT is allowed
* Donors must be:

  * Human leukocyte antigen (HLA)-identical related donors or
  * Unrelated donors matched for HLA-A, B, C, DRB1, and DQB1 defined by high resolution deoxyribonucleic acid (DNA) typing or mismatched for one HLA allele, except for HLA-C where no mismatch is allowed
  * Able to undergo peripheral blood stem cell collection or bone marrow harvest
  * In good general health, with a Karnofsky or Lansky Play Performance score \> 90%
  * Able to give informed consent (if \> 18 years), or with a legal guardian capable of giving informed consent (if \< 18 years)
* Acute lymphoblastic leukemia (ALL): all ALL patients not eligible for other protocols

Exclusion Criteria:

* Receiving umbilical cord blood
* With impaired cardiac function as evidenced by ejection fraction \< 35% or cardiac insufficiency requiring treatment or symptomatic coronary artery disease
* With impaired pulmonary function as evidenced by partial pressure of oxygen (pO2) \< 70 mm Hg and diffusing capacity of the lung for carbon monoxide (DLCO) \< 70% of predicted or pO2 \< 80 mm Hg and DLCO \< 60% of predicted; or receiving supplementary continuous oxygen
* With impaired renal function as evidenced by creatinine-clearance \< 50% for age, weight, height or serum creatinine \> 2x upper normal limit or dialysis-dependent
* With hepatic dysfunction as evidenced by total bilirubin or aspartate aminotransferase (AST) or alanine aminotransferase (ALT) \> 2.0 x upper normal limit or evidence of synthetic dysfunction or severe cirrhosis
* With active infectious disease requiring deferral of conditioning, as recommended by an Infectious Disease specialist
* With human immunodeficiency virus (HIV)-positivity or active infectious hepatitis because of possible risk of lethal infection when treated with immunosuppressive therapy
* With central nervous system (CNS) leukemic involvement not clearing with intrathecal chemotherapy and/or cranial radiation prior to initiating conditioning (day -6)
* With life expectancy severely limited by diseases other than malignancy
* Women who are pregnant or lactating because of possible risk to the fetus or infant
* With known hypersensitivity to treosulfan and/or fludarabine
* Receiving another experimental drug within 4 weeks before initiation of conditioning (day -6)
* Unable to give informed consent (if \> 18 years) or with a legal guardian (if \< 18 years) unable to give informed consent
* Ineligible donors will be those:

  * Deemed unable to undergo marrow harvesting or PBSC mobilization and leukapheresis
  * Who are HIV-positive
  * With active infectious hepatitis
  * Females with a positive pregnancy test
  * Unable to give informed consent (if \> 18 years) or with a legal guardian (if \< 18 years) unable to give informed consent