Emerging Role of Chimeric Antigen Receptor-Natural Killer Cells for the Treatment of Hematologic Malignancies

The clinical use of T lymphocytes engineered with chimeric antigen receptors (CARs) has revolutionized the treatment of patients with refractory or relapsed hematological malignancies. CAR natural killer (CAR-NK) cells are NK cells engineered with CARs to specifically target cell antigens expressed on the membrane of tumor cells. CAR-NK cells could offer some advantages with respect to CAR-T cells, related to their specific and innate anti-tumor activity, availability as an "off the shelf" cellular therapy, reduced costs, and improved safety. Promising efficacy of CAR-Nk cell therapy was observed in clinical trials based on the treatment of some hematological malignancies. However, to date, the clinical experience of CAR-NK cell therapy has been preliminary, with the evaluation of only a limited number of patients. Furthermore, CAR-NK cell therapy has been limited by the short persistence of these cells and by the suboptimal cytotoxic activity of some CAR-NK preparations. Therefore, studies based on the enrollment of a number of patients is required to carefully assess and confirm the safety and the efficacy of CAR-NK cell therapy in hematological malignancies and to compare their efficacy with respect to allogeneic CAR-T cells.