A review of CD19-targeted immunotherapies for relapsed or refractory acute lymphoblastic leukemia

Aim Novel immunotherapies have generated high response rates and unique adverse effects among patients with relapsed or refractory acute lymphoblastic leukemia. Therapies engaging endogenous T-cells against acute lymphoblastic leukemia are emerging for children and adults with various poor prognostic factors, thus accurate knowledge of immunotherapies is necessary for their effective implementation in the future. In this review, we evaluate clinical trial data regarding chimeric antigen receptor T-cells and blinatumomab, for the treatment of relapsed or refractory acute lymphoblastic leukemia. Summary In the relapsed or refractory setting, response rates rapidly diminish after subsequent lines of chemotherapy and cumulative toxicities may cause significant patient harm. Immunotherapies provide an approach to improve response rates and minimize traditional toxicities via novel mechanisms of action. Two therapies targeting CD19 antigens expressed on B-cell acute lymphoblastic leukemia lineages, chimeric antigen receptor T-cells, and blinatumomab have induced complete remissions among high-risk patient populations, especially those refractory to multiple therapies. Adverse effects such as cytokine release syndrome and neurologic sequelae remain serious precautions of each therapy. Conclusion Knowledge of immunotherapy mechanisms and clinical outcomes associated with immunotherapies is critical for the optimization of treating patients with relapsed or refractory acute lymphoblastic leukemia. Future use of chimeric antigen receptor T-cells and blinatumomab demands proper assessment of a patient's disease and treatment history in addition to unique monitoring and supportive care interventions.