Busulfan and Cyclophosphamide Followed By ALLO BMT

Inclusion Criteria:

Diagnosis of acute lymphoblastic leukemia (ALL), acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS) and current in complete remission meeting one of the following:

<45 years of age who are at least 6 months after initial hematopoietic stem cell transplant (HSCT)
<45 years of age and have received sufficient radiation treatment to be ineligible for total body irradiation (TBI) containing preparative therapy
Karnofsky performance status >70% or if <16 years of age, a Lansky play score >50

Adequate major organ function including:

cardiac: left ventricular ejection fraction >45% by echocardiogram (ECHO/MUGA)
renal: creatinine clearance >40 mL/min/1.73m^2
hepatic: no clinical evidence of hepatic failure (e.g., coagulopathy, ascites)

An acceptable source of stem cells according to current University of Minnesota Bone Marrow Transplant program guidelines. Acceptable stem cell sources include:

HLA-matched related or unrelated donor bone marrow (6/6 or 5/6 antigen match)
HLA-matched related or unrelated donor peripheral blood stem cells
related or single or double unrelated donor umbilical cord blood (6/6, 5/6 or 4/6 match)
Women of childbearing age must have a negative pregnancy test and all sexually active participants must agree to use effective contraception during study treatment
Written consent (adult or parent/guardian)

Exclusion Criteria:

eligible for TBI containing preparative regimen
active uncontrolled infection within one week of study enrollment
pregnant or lactating female