Abstract 5622: Development of allogeneic TCR-mimic activating gdT (TAG-T) cells targeting KRASG12D/HLA-A*11 pMHC for undruggable KRAS-mutated cancers

Abstract The therapeutic antibodies are at the vanguard of the most promising cancer treatments. Whereas conventional therapeutic antibodies have been limited to extracellular antigens, T cell receptor mimic (TCRm) antibodies can target intracellular antigens presented by cell surface major histocompatibility complex (MHC) proteins. We successfully obtained KRASG12D/HLA-A*11-specific TCRm antibodies from a phage display using a human scFv library. The affinity and target binding specificity of TCRms was validated by SPR and flow cytometry. Then, the KRASG12D/HLA-A*11-specific TAG receptor was designed as a double-chain, TCR-based construct, with the KRASG12D/HLA-A*11-specific TCRm fused to the N-terminus of the human TCR-Cγ and TCR-Cδ chain with Furin-P2A linker sequence. In vitro and in vivo cytotoxicity assays demonstrated that the KRASG12D/HLA-A*11-specific TAG-T cells exhibited high cytotoxic activity against KRASG12D/HLA-A*11-positive cells. Furthermore, TAG-T cells engineered with a co-stimulatory domain and a chimeric switching receptor (CSR) showed the highest anticancer activity and proliferation both in vitro and in vivo. Therefore, our results demonstrate that the TCRm-based TAG-T platform targeting KRASG12D/HLA-A*11 represents a novel and promising allogeneic cell therapy strategy for patients with KRAS-G12D-positive cancers. Citation Format: Chia-Chun Chao, Hsin-Yu Chang, Wei-Ze Hong, Jhen-Yu Chen, Yi-Wen Jiang, K.S. Clifford Chao, Kevin Chih-Yang Huang. Development of allogeneic TCR-mimic activating gdT (TAG-T) cells targeting KRASG12D/HLA-A*11 pMHC for undruggable KRAS-mutated cancers abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 5622.