Chimeric antigen receptor-based cellular therapy for T-cell malignancies

Chimeric antigen receptor (CAR) T-cell therapy utilizes synthetic biology techniques to engineer T cells to specifically target tumor cells using most commonly single-chain variable fragments (scFvs) to recognize tumor-associated antigens, which has been successfully applied to patients with B-lineage hematologic malignancies including leukemia, lymphoma and multiple myeloma. However, treatment outcomes for relapsed or refractory (R/R) T-cell malignancies remain suboptimal. A significant challenge is the shared antigens between malignant and normal T cells, leading to fratricide among CAR T cells. Moreover, the presence of malignant T cells in patients' leukapheresis may increase risk of relapse. Post-infusion, patients may experience severe T-cell aplasia, rendering the cancer patients who are generally immunocompromised even more immunodeficient. This review article explores CAR-based cellular therapy, including immune effector cells (IECs) such as conventional T cell subsets, natural killer (NK) cells, natural killer T (NKT) cells, cytokine-induced killer (CIK) cells, and γδ T cells for T-cell malignancies. We discuss multiple antigen-targeting, emerging technologies, and the latest clinical trials in attempt to improve CAR-based therapy for T-lineage neoplasms.