CAR density influences antitumoral efficacy of BCMA CAR T cells and correlates with clinical outcome

Abstract

Identification of new markers associated with long-term efficacy in patients treated with CAR T cells is a current medical need, particularly in diseases such as multiple myeloma. In this study, we address the impact of CAR density on the functionality of BCMA CAR T cells. Functional and transcriptional studies demonstrate that CAR T cells with high expression of the CAR construct show an increased tonic signaling with up-regulation of exhaustion markers and increased in vitro cytotoxicity but a decrease in in vivo BM infiltration. Characterization of gene regulatory networks using scRNA-seq identified regulons associated to activation and exhaustion up-regulated in CAR High T cells, providing mechanistic insights behind differential functionality of these cells. Last, we demonstrate that patients treated with CAR T cell products enriched in CAR High T cells show a significantly worse clinical response in several hematological malignancies. In summary, our work demonstrates that CAR density plays an important role in CAR T activity with notable impact on clinical response.

CTLA-4 tail fusion enhances CAR-T anti-tumor immunity

“…In line with this, our data show that regulating CAR signaling strength with CCT fusion prevents CAR-T cells from excessive stimulation and enables durable response against tumor cells. CAR signaling needs to be tightly regulated to achieve the fine-tuned balance of sufficient signaling for effective tumor antigen detection and CAR-T action, while also circumventing the detrimental effects seen in CARs with an excessively high affinity or expression 8, 50, 51 . This resonates in our results with CAR-3CCT cells, as these cells exhibited the best killing capability under repeated stimulation in vitro yet performed worse than the control CAR-T cells in vivo .…”

CAR-T cells targeting HLA-G as potent therapeutic strategy for EGFR-mutated and overexpressed oral cancer

“… 58 , 59 Previous studies demonstrate that CAR functionality is regulated by the density of target antigen, and low antigen expression contributes to the limitation of antitumor efficacy of CAR-T cells. 60 , 61 Our in vitro studies addressed the safety issue in using human normal tissue array chips and examined the cell killing ability within anti-HLA-G CAR-T cell therapy in primary cell cultures. Our animal study has also demonstrated that there was no adverse reaction during anti-HLA-G CAR-T cell treatment.…”

Innovation in BCMA CAR-T therapy: Building beyond the Model T

“…Translational research suggests that CAR density and antigen binding affinity influence the functionality of BCMA CAR-T cells in unexpected ways. While one might suspect that more CARs per individual T cell would correspond to more cancer cell death, higher CAR expression may actually be associated with increased T-cell exhaustion and decreased CAR-T cell infiltration into the bone marrow ( 16 ). In the future, modifications to viral promoter genes or CRISPR-mediated precision regarding the location of CAR insertion into the host genome may allow for manipulation of expected levels of CAR expression per cell ( 17 – 19 ).…”