Abstract C003: High-throughput discovery of rare anti-tumor TCRs via synthetic yeast-based libraries

Abstract Soluble T-cell receptor (TCR)-based therapeutics can potently and specifically target otherwise inaccessible intracellular tumor antigens via peptide-HLA (pHLA) recognition. However, conventional methods to identify patient-derived receptors often yield soluble TCRs with poor affinities and poor expression, requiring extensive engineering for use in clinically validated T cell engager therapeutic formats. In addition, these methods can fail to identify TCRs with rare specificities due to their limited throughput and the pruning of natural TCR repertoires during thymic education. Here, we employed high-throughput methods to discover and characterize highly developable soluble TCRs with high affinities and rare specificity profiles from the first fully human TCR libraries built in yeast. We identified synthetic TCRs that simultaneously bound with high affinity to three distinct tumor-associated pHLA antigens, unlocking new opportunities for potent multi-epitope targeting of cancer cells. We further identified synthetic TCRs that bound with supraphysiological affinities to a pHLA antigen derived from an oncogenic driver mutation that also exhibited exquisite specificity for the mutated epitope. Together, these results highlight a powerful new approach for rapidly discovering rare and highly developable soluble TCRs, accelerating the development of potent and specific TCR-based T cell engager therapeutics for the treatment of cancer. Citation Format: Tse-han Kuo, Vivien Qiao, Joseph Brouillard, Akila Katuwawala, Nicholas Luey, Jonas Spaulding, Mrunal Sakharkar, Patricia Sackett, Whitney Renaud, Morgan Morrill, Allie LeMay, Hannah Green, John Horangic, Shu Lin, Beth Sharkey, Christin Strong, Elizabeth Parker, Tushar Jain, James Geoghegan, Arvind Sivasubramanian, Eric Krauland, Garrett Rappazzo. High-throughput discovery of rare anti-tumor TCRs via synthetic yeast-based libraries [abstract]. In: Proceedings of the AACR Immuno-Oncology Conference (AACR IO): Discovery and Innovation in Cancer Immunology: Revolutionizing Treatment through Immunotherapy; 2026 Feb 18-21; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Immunol Res 2026;14(2 Suppl):Abstract nr C003.