A universal and switchable CAR T cell therapy platform (zCART) targeting tumor antigens and the immunosuppressive microenvironment

The major hurdles in the treatment of solid tumors with chimeric antigen receptor (CAR) T cell therapies are antigen heterogeneity and the immunosuppressive tumor microenvironment. To address these challenges, we developed a universal and switchable CAR T cell therapy platform (zCART) that utilizes cotinine, a pharmacologically inert hapten, as a molecular bridge between anti-cotinine CAR T cells and tumor cells via cotinine-conjugated affibodies. First, we generated two affibody switches targeting distinct tumor-associated antigens and one affibody switch targeting an immune-oncology molecule. In vitro studies demonstrated that all three cotinine-conjugated affibodies, when combined with anti-cotinine CAR T cells, induced potent, dose-dependent cytotoxicity against target-expressing tumor cells. The combination of distinct affibody switches resulted in enhanced anti-tumor activity. These results highlight that the cotinine-based, switchable CAR T cell therapy platform enables flexible, multi-target control of CAR T cell activity and effective elimination of heterogeneous solid tumors. By decoupling antigen recognition from CAR T cell activation, the zCART platform offers a safe, versatile, and next-generation approach to overcoming tumor antigen variability and the immunosuppressive microenvironment, positioning it as a promising strategy for solid-tumor immunotherapy.