This phase II trial studies how well blinatumomab works in treating patients with B-cell acute lymphoblastic leukemia whose disease is in remission (causes no symptoms or signs) but is still present in a small number of cells in the body (minimal residual disease). Immunotherapy with monoclonal antibodies, such as blinatumomab, may induce changes in the body's immune system and may interfere with the ability of tumor cells to grow and spread.

PRIMARY OBJECTIVES:

I. To evaluate the clinical efficacy of blinatumomab in patients B-cell acute lymphoblastic leukemia in complete morphologic remission with positive minimal residual disease (MRD) in terms of relapse-free survival (RFS).

SECONDARY OBJECTIVES:

I. To evaluate other efficacy endpoints such as overall survival and MRD negativity rate by flow cytometry and/or polymerase chain reaction (PCR) overall and after the first cycle, as well as safety of blinatumomab in this setting.

OUTLINE:

Patients receive blinatumomab intravenously (IV) continuously on days 1-28. Treatment repeats every 6 weeks for up to 5 cycles in the absence of disease progression or unacceptable toxicity. Patients who do not proceed with stem cell transplantation may receive blinatumomab IV maintenance therapy with one cycle every 3 months for up to 4 cycles. Patients who remain in MRD remission for 3 months and then become MRD positive again can be retreated following the same treatment plan previously received.

After completion of study treatment, patients are followed up every 6 months.

Inclusion Criteria:

• Patients with B-lineage acute lymphocytic leukemia (ALL) in hematologic complete remission (CR) with molecular failure (i.e., had never achieved an MRD-negativity status before blinatumomab) or had a molecular relapse (i.e., became MRD positive after having been MRD negative) starting at any time point after 3 months of frontline therapy; molecular disease or minimal residual disease is defined by a value of at least of 1 x 10^-4 (0.01%) by multicolor flow cytometry and/or by next generation sequencing (NGS)
• Patients with B-lineage ALL in hematologic complete remission (CR) with molecular failure (i.e., had never achieved an MRD-negativity status before blinatumomab) or had a molecular relapse (i.e., became MRD positive after having been MRD negative) starting at any time point after 3 months of frontline therapy; molecular disease or minimal residual disease is defined by a value of at least of 1 x 10-4 (0.01%) by multicolor flow cytometry and/or by next generation sequencing (NGS)
• Performance status of 0, 1, or 2
• Creatinine clearance >= 30 ml/minute
• Bilirubin less than or equal to 3.0 mg/dL
• No active or co-existing malignancy with life expectancy less than 12 months
• Patients with Philadelphia chromosome positive (Ph+) ALL can be enrolled in CR1 or CR2 and beyond; a tyrosine kinase inhibitor (TKI) will be added at the discretion of the treating physician; MRD for these patients will be defined by PCR of 0.1% and above (International Scale)

Exclusion Criteria:

• Pregnant or nursing women
• Known to be human immunodeficiency virus positive (HIV+)
• Active and uncontrolled disease/infection as judged by the treating physician
• Unable or unwilling to sign the consent form
• Active central nervous system (CNS) or extramedullary disease
• Monoclonal antibodies therapy within 2 weeks before study entry
• Radiotherapy and cancer chemotherapy (except for intrathecal prophylaxis and/or low-dose maintenance therapy such as vinca alkaloids, mercaptopurine, methotrexate, steroids) or any investigational drug within 2 weeks before study entry