This is a study looking at how well the combination treatment of Blinatumomab and Nivolumab works in patients with first relapse of B-cell Acute Lymphoblastic Leukemia (B-ALL) as compared to treatment with only Blinatumomab. In addition, it is looking at what effects, good and/or bad the treatment has. First relapse means that B-ALL has come back after the initial treatment a patient received for B-ALL. All patients will receive treatment with Blinatumomab, an antibody (protein) that targets a marker on B-ALL cells and then uses your immune system to kill the B-ALL cell. Some patients will...
