Neoadjuvant Pediatric Leukemia AALL1821

This phase II trial studies the effect of nivolumab in combination with blinatumomab compared to blinatumomab alone in treating patients with B-cell acute lymphoblastic leukemia (B-ALL) that has come back (relapsed). Down syndrome patients with relapsed B-ALL are included in this study. Blinatumomab is an antibody, which is a protein that identifies and targets specific molecules in the body. Blinatumomab searches for and attaches itself to the cancer cell. Once attached, an immune response occurs which may kill the cancer cell. Nivolumab is a medicine that may boost a patient's immune system. Giving nivolumab in combination with blinatumomab may cause the cancer to stop growing for a period of time, and for some patients, it may lessen the symptoms, such as pain, that are caused by the cancer.