A drug used to treat B-cell acute lymphoblastic leukemia that is Philadelphia chromosome negative and has come back or has not gotten better with other anticancer treatment. It is also being studied in the treatment of other types of cancer. Blinatumomab binds to a protein called CD19, which is found on most B cells (a type of white blood cell) and some types of leukemia cells. It also binds to a protein called CD3, which is found on T cells (a type of white blood cell). This may help the immune system kill cancer cells. Blinatumomab is a type of monoclonal antibody. Also called Blincyto.