Blinatumomab is a recombinant mouse derived bispecific monoclonal antibody to the CD3 cell surface antigen found on T lymphocytes and the CD19 site for the targeted (malignant) B lymphocytes. Blinatumomab is approved for use as a second line treatment of relapsed or refractory B cell precursor related acute lymphoblastic leukemia (ALL). Blinatumomabis commonly associated with mild-to-moderate serum enzyme and bilirubin elevations during the first cycle of therapy, but it has not been linked to cases of clinically apparent liver injury.