Abstract 880: Allogeneic CAR-T cell products containing 10 gene edits using CRISPR/Cas9 can retain full functionality in vivo and in vitro

Abstract

Abstract Hematologic malignancies have proven most responsive to CAR-T therapies. However, there is significant variability in the depth and duration of response to autologous CAR-T cells. Furthermore, CAR-T responses in solid malignancies have been minimal. T cells from cancer patients can be compromised by the disease and prior treatments, and the use of allogeneic CAR-T products could potentially provide a more robust therapy. However, even CAR-T cells from healthy donors may benefit from additional gene edits that could enhance effector function, increase durability, evade immune mechanisms and/or combat the tumor microenvironment. These types of additional CAR-T features are readily enabled by CRISPR/Cas9 technology. While recent clinical data has demonstrated the persistence of therapeutic T cells that had been edited with CRISPR, the extent of gene editing that therapeutic T cells can tolerate has not been fully described. Herein, we have generated CAR-T cells with 10 gene edits. Loss of function alleles were produced in 9 genes and a CAR cassette was knocked into the TRAC locus via homology-directed repair. CD19-directed CAR-T cells with these 10 gene edits were fully functional in vitro, as shown by their ability to expand and kill target cells and secrete cytokines while remaining non-transformed. These cells were also highly efficacious in an in vivo model of CD19+ malignancy. Importantly, these edits, which produced insertions and deletions in target genes, could be detected in the blood of mice several months post injection. These data demonstrate that CRISPR/Cas9 can be used to create highly edited allogeneic CAR-T cells, unlocking the potential to enhance many functions relevant to CAR-T health and anti-tumor activity. Citation Format: Brigid McEwan, Meghna Kuppuraju, Zinkal Padalia, Jonathan Terrett, Demetrios Kalaitzidis. Allogeneic CAR-T cell products containing 10 gene edits using CRISPR/Cas9 can retain full functionality in vivo and in vitro [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 880.