The success of allogeneic stem cell transplantation has demonstrated the potential for immunotherapy to treat acute myeloid leukemia (AML). Although alternative T-cell-based immunotherapies have shown efficacy, they also pose the risk of on-target off-leukemia hematotoxicity. So far, adoptive autologous or allogeneic chimeric antigen receptor (CAR) T/natural killer cell therapy is almost exclusively employed as a bridge-to-transplant strategy in the context of clinical trials. For now, clinical trials predominantly target lineage-restricted antigens, but emerging approaches focus on leukemia-associated/specific intracellular target antigens, including dual and split targeting strategies. Adapter CAR T cells and T-cell-recruiting bispecific antibodies offer transient exposure with enhanced safety and multitargeting potential against antigen-escape variants. However, these have yet to demonstrate sustained responses and should be used earlier to treat low leukemia burden, preferably if measurable residual disease is present. To address immune dysregulation and enhance T-cell fitness, novel CAR T and bispecific designs, along with combinatorial strategies, might prove essential. Furthermore, genetic associations with inflammatory bone marrow signatures suggest the need for tailored platforms in defined AML subtypes. The eagerly anticipated results of trials investigating magrolimab, an anti-CD47 antibody targeting the "do not eat me" signal in p53-mutated AML, should shed further light on the potential of these evolving immunotherapeutic approaches.
Copyright © 2023 by The American Society of Hematology.