Blinatumomab Maintenance Following Allogeneic Hematopoietic Cell Transplantation for Patients With Acute Lymphoblastic Leukemia

Inclusion Criteria:

1. Patients 1-70 years of age.
2. Patients with B-lineage ALL in a) hematologic complete remission (CR) beyond CR1 at time of transplant; patients beyond CR1 or with primary induction failure may be without minimal residual disease, b) any residual disease defined by positive flow \>0.01%, detection of BCR-ABL transcript by PCR with a sensitivity of 1/10,000, or detection of the t(9;22) translocation in any metaphases by cytogenetics at time of transplant, or presence of the MLL gene.
3. Received an allogeneic HCT within the last 100 days. Enrollment within 30-100 days after transplant, and after adequate recovery of counts defined as ANC \>/= 0.5 x 10\^9/L without daily use of myeloid growth factor and platelet \> 20 x 10\^9/L without platelet transfusion within 1 week, and adequate organ function to receive blinatumomab defined as creatinine clearance greater than 30 ml/min, ALT/AST \< 5 x ULN and serum bilirubin \< 3 x ULN.
4. Performance status of 0, 1, or 2. Karnofsky (or Lansky for subjects \< 16 years old) performance status \>/= 50.

Exclusion Criteria:

1. Relapsed ALL defined as \>5% malignant blasts in bone marrow or peripheral blood.
2. Active GVHD requiring systemic steroid therapy. Medications for GVHD prophylaxis are acceptable.
3. Systemic steroid therapy unless for physiologic replacement
4. Uncontrolled disease/infection as judged by the treating physician
5. Active ALL in the central nervous system (CNS), as defined by \>/= 5 leukocytes per microL with identifiable blast cells in the CSF, and/or the presence of cranial-nerve palsies
6. Pregnant or nursing women