Abstract 29: A genetically modified tumor-infiltrating lymphocytes product (GT216) enhanced anti-tumor efficacy against solid tumor by fine-tuning multiple negative immune regulators

Abstract Adoptive cell therapy by tumor-infiltrating lymphocytes (TILs) has demonstrated promising clinical benefits for patients with solid tumors. However, the large-scale expansion during manufacture may drive hypofunction or exhaustion status of the final TIL product, leading to impaired anti-tumor efficacy and persistence post infusion. Grit Biotechnology designed a genetically engineered TIL product (GT216) to overexpress an intracellular protein that is induced by antigen-specific T cell response and mediates the degradation of multiple immunoregulatory molecules, which releases the therapeutic potential of TIL with enhanced cytotoxicity as well as persistence in vitro and in vivo. Multiple vector construct designs of GT216 were compared and the best design was selected based on stable and efficient expression of surrogate marker in TILs. GT216 could be successfully manufactured by Grit’s StemTexp® and StaViral® platforms with good memory phenotype and no signs of overactivation or exhaustion. In vitro functional analysis showed that GT216 demonstrated significantly increased cytotoxicity and cytokine production when cocultured with tumor cells and better tumor control ability during a serial killing assay than conventional TILs. Notably, GT216 TILs eradicated tumor growth with low IL-2 support in NOG mice inoculated with HLA-matched tumor cells while conventional TILs showed limited tumor control with high IL-2, corelated with their better infiltration and persistence in tumor and periphery. In summary, GT216 demonstrated enhanced anti-tumor efficacy and persistence as well as reduced IL-2 dependency in vitro and in vivo, supporting the clinical evaluation of GT216 as a next-generation TIL therapy in treatment of refractory solid tumors. Citation Format: Jingwei Sun, Yiyang Tan, Jiahui Jin, Jingman Wang, Lingyun Chen, Fengbiao Guo, Yongchao Tan, Zhao Xu, Yarong Liu. A genetically modified tumor-infiltrating lymphocytes product (GT216) enhanced anti-tumor efficacy against solid tumor by fine-tuning multiple negative immune regulators abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts) ; 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84 (6Suppl): Abstract nr 29.