Monoclonal antibodies and immune therapies for adult precursor B-acute lymphoblastic leukemia

Adult B-acute lymphoblastic leukemia (B-ALL) does not share the favorable prognosis seen in pediatric patients with the same disease. Less than 50% of patients experience long-term survival and for those adults over age 60, long-term survival is only 10%. At time of relapse, 5-year prognosis is a dismal 7%. Novel and less toxic agents are urgently needed. The last few years have seen a surge in immune therapies for B-ALL. These agents may target CD19, CD20, CD22, and less frequently CD52. Expression of these surface markers and the drugs which target them are discussed. Some immune therapies are simple monoclonal antibodies against B lymphocyte markers such as rituximab, ofatumumab, and epratuzumab. Others are in a class of antibody-drug conjugates which link a highly toxic chemotherapy to a monoclonal antibody for targeted delivery, such as inotuzumab and denintuzumab. Finally, novel immune therapies recruit (in the case of bispecific T cell engager [BiTE]) or modify (in the case of chimeric antigen receptor [CAR] T cells) one's own T cells to fight leukemic cells. This article reviews the rationale, clinical data, and toxicity profiles of immune therapies approved or in late stages of development for B-ALL.