The Identification of IL-4 as a Regulator of Chimeric Antigen Receptor T Cell Exhaustion

Durable response to chimeric antigen receptor T (CART) cell therapy remains limited in part due to CART cell exhaustion. We investigated the regulation of CART cell exhaustion with three independent approaches including: a genome-wide CRISPR knockout screen using a validated in vitro model for exhaustion, RNA and ATAC sequencing on baseline and chronically stimulated CART cells, and RNA and ATAC sequencing on pre-infusion CART cell products from responders and non-responders in the ZUMA-1 clinical trial. Each of these approaches identified IL-4 as a key regulator of CART cell dysfunction. Further, when CART cells were treated with IL-4, they developed signs of exhaustion, but when CART cells were treated with an IL-4 monoclonal antibody, they showed improved antitumor efficacy and reduced signs of exhaustion in preclinical models. Therefore, our study identified both a novel role for IL-4 on CART cells and the improvement of CART cell therapy through IL-4 neutralization. Statement of Significance Identifying regulators of CART cell exhaustion will not only enhance the field’s understanding of therapeutic failure, but it will also provide avenues to enhance CART cell efficacy. This study reveals both a novel role for IL-4 in exhaustion and a strategy to improve CART cell activity through IL-4 neutralization.