Abstract 4062: The discovery and development of a CRISPR/Cas9-engineered tumor-infiltrating lymphocytes product (GT316) as a next-generation TIL therapy

Abstract Adoptive cell therapy by tumor-infiltrating lymphocytes (TILs) has demonstrated promising therapeutic effects in multiple types of solid tumors and significantly prolonged the survival of late-stage patients. However, the “prone-to-exhaustion” phenotype of the final TIL product after rapid expansion during manufacture and the presence of various immunosuppressive mechanisms in tumor microenvironment (TME) compromises the persistence and anti-tumor efficacy of TIL post infusion. To discover potential immunoregulatory targets that could maximize the function of TIL, we established a genome-wide CRISPR/Cas9 screening platform, ImmuT Finder®, to unbiasedly identify functional gene targets in primary T cells. Notably, this platform employed T cells bearing a tumor-antigen specific TCR-T that were repeatedly stimulated by tumor cells with cognate tumor antigen and demonstrated similar exhaustion profile as TIL. We selected top 30 targets after several rounds of screening and quickly validated their function in a 96-well array. Then, the top targets that showed significantly enhancement in proliferation and function of TCR-T were further selected, and their combinational effects on TIL were tested both in vitro and in vivo. Finally, double KO of GT304 and GT312 (GT316) stands out as the most potent combination, which significantly improves TIL proliferation and cytokine release, eradicates tumor growth in both CDX and PDX mouse models and promotes long-term in vivo persistence with low-dependence on IL-2. Specific and potent sgRNAs targeting both targets have been selected, and manufacturing process of GT316 TIL product has been developed (KOReTIL®). In summary, these data demonstrated that our ImmuT Finder® platform enables unbiased discovery of potent and novel targets for the development of T cell therapy and support the clinical assessment of GT316 as a next-generation TIL therapy. Currently, an investigator-initiated trial of GT316 is ongoing in China. Citation Format: Yarong Liu, Jingwei Sun, Yao Sheng, Jingman Wang, Jiahui Jin, Fei Li, Lingyun Chen, Di Zhou, Yongchao Tan, Quanwei Wang, Zhao Xu, Haibao Li, Pin Wang, Jun Cui. The discovery and development of a CRISPR/Cas9-engineered tumor-infiltrating lymphocytes product (GT316) as a next-generation TIL therapy. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4062.