Spatially controlled enhanced anti-tumor efficacy via CAR T cells engineered with a CTLA-4-based autoregulated circuit

The widespread application of CAR T cell therapy to solid tumors is hindered by antigen expression heterogeneity, on-target off-tumor toxicity, and limited functional persistence of CAR T cells. Next generation engineering strategies aiming to overcome these hurdles rely on multiple antigen-targeting approaches that fail to simultaneously address all the limitations and/or the use of synthetic receptor transcriptional circuits, which suffer from slow activation kinetics. Here, we leveraged the unique trafficking properties of CTLA-4, regulated by a rapid internalization process, to create CTLA-4-based activation-inducible antigen receptors (CAVI-Rs). CAVI-Rs were exclusively expressed on T cells upon activation with remarkably fast on/off kinetics and self-sustainable expression. In in vitro and in vivo models of heterogeneous tumors, CAR+CAVI-R dual-engineered T cells demonstrated enhanced cytotoxicity and tumor-selective, spatially restricted functionality. Additionally, intermittent co-expression of the CAVI-R lead to improved T cell metabolic and transcriptional fitness, resulting in superior expansion, persistence and anti-tumor efficacy. The CAVI-R provides a novel, simple, safe, potent, and fully-human approach to expand CAR T cell applicability while improving anti-tumor outcomes.