Bispecific Antibody Armed Metabolically Enhanced Headless CAR T Cells

Adoptive T cell therapies for solid tumors is challenging. We generated metabolically enhanced co-activated-T cells by transducing intracellular co-stimulatory (41BB, ICOS or ICOS-27) and CD3 zeta T cell receptor signaling domains followed by arming with bispecific antibodies (BiAbs) to produce armed Headless CAR T cells (hCART). Various hCART armed with BiAb directed at CD3 epsilon and various tumor associated antigens were tested for: 1) specific cytotoxicity against solid tumors targets; 2) repeated and dual sequential cytotoxicity; 3) survival and cytotoxicity under in vitro hypoxic condition; and 4) cytokine secretion. The 41BB zeta transduced hCART (hCART(41BB zeta)) armed with HER2 BiAb (HER2 hCART(41BB zeta)) or armed with EGFR BiAb (EGFR hCART(41BB zeta)) killed multiple tumor lines significantly better than control T cells and secreted Th-1 cytokines/chemokines upon tumor engagement at effector to target ratio (E:T) of 2:1 or 1:1. HER2 hCART serially killed tumor targets up to 14 days. Sequential targeting of EGFR or HER2 positive tumors with HER2 hCART(41BB zeta) followed by EGFR hCART(41BB zeta) showed significantly increased cytotoxicity compared single antigen targeting and continue to kill under in vitro hypoxic conditions. In summary, metabolically enhanced headless CAR T cells are effective serial killers of tumor targets, secrete cytokines and chemokines, and continue to kill under in vitro hypoxic condition.

Automated summary

In this study, metabolically enhanced headless CAR T cells were generated by transducing specific signaling domains and arming with bispecific antibodies, which showed significant cytotoxicity and prolonged killing effect on solid tumor targets, while also maintaining efficacy under in vitro hypoxic conditions.