Single-Step Precision Genome Engineering Platform Enables Versatile Generation Of Personalized (Neotcr) Adoptive Cell Therapy T Cells With Supplementary Anti-Tumor Attributes.

Abstract Personalized autologous TCR-T cell therapies targeting neoE-specific neoepitopes (NeoE) derived from tumor-exclusive mutations are a compelling approach for the treatment of patients with solid tumors. Using the ultra-sensitive imPACT Isolation Technology®, antigen-experienced neoE-specific CD8 T cells are captured from the blood of patients with solid cancers followed by cloning of the cognate neoepitope-specific HLA class I-restricted T cell receptors (HLA-I neoTCRs). Using DNA-mediated (non-viral) precision genome engineering technology, fresh CD8 and CD4 T cells from the same patient with cancer are engineered to express the HLA-I neoTCR. We have further innovated this platform of precision genome engineering to confer neoTCR-T cells with supplementary gene edits to address the array of potential sources for tumor immune evasion. Two examples of the versatility of this single step gene editing platform are described in this study: 1) concurrent expression of a CD8 co-receptor (CD8coR) to augment activity of CD4 T cells engineered with lower affinity HLA-I neoTCRs; and 2) simultaneous disruption of TET2 expression in T cells, which has previously been reported to positively affect T cell differentiation and persistence. The data shows that these simultaneous supplemental gene modifications were achieved with high efficiency, resulting in fully functional CD8 and CD4 neoTCR-T cells. Surface expression of CD8coR together with the neoE-targeted TCR increased T cell effector function and antigen-specific tumor cell killing. NeoTCR-T cells with concomitant deletion of TET2-expression exhibited enhanced cytotoxicity against neoantigen-expressing tumor cells. Together, these results demonstrate the applicability of this versatile precision genome engineering platform technology to yield enhanced next generation neoTCR-T cell therapies to expand the potential for clinical benefit in treating persons with solid cancers. Citation Format: Michael M. Dubreuil, Charles W. Tran, Bhamini Purandare, William Lu, James Byers, Michal Mass, Kyle Jacoby, Barbara Sennino, Alex Franzusoff, Stefanie J. Mandl. Single-step precision genome engineering platform enables versatile generation of personalized (neoTCR) adoptive cell therapy T cells with supplementary anti-tumor attributes [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1526.