Researchers in Spain believe that a new type of CAR therapy using natural killer cells, could be more effective and have fewer side effects in treating blood cancers like multiple myeloma than CAR T cell therapy. 

CAR T cell therapy is a growing field of myeloma research, but it can come with significant side effects like cytokine release syndrome (CRS) and neurotoxicities. Researchers are looking for both ways to improve CAR T therapies and to develop new approaches that may be equally good with fewer toxicities.

Spanish researchers of the H12O-CNIO Haematological Malignancies Clinical Research Unit, led by hematologist Joaquín Martínez, found that a similar CAR treatment using natural killer cells (NK cells) instead of T cells was more effective and had fewer side effects in mice with multiple myeloma. Early in-human trials are now planned. 

The researchers hypothesized that CAR-NK cells could be less toxic when targeting resistant myeloma cells. In their study, they analyzed the anti-tumor activity of activated and expanded NK cells (NKAE) and CD45RA^- T cells from multiple myeloma patients that were engineered to express an NKG2D-based CAR that target antigens of the NKG2D receptor, which are not typically found on normal cells but are present in over 70% of human cancers.

“Overall, our results show that it is possible to modify autologous NK cells from multiple myeloma patients to safely express a NKG2D-CAR. These cells […] could be an effective strategy against multiple myeloma”, says Martínez-López.