Harnessing Pluripotent Stem Cells for Cancer Immunotherapy: The Development of TCR-less CAR-T Cells

Genetically engineered T cells represent a significant advancement in cancer and immune disorder treatments, with CAR-T cell therapy showing remarkable clinical outcomes, particularly for B cell ALL. Despite the promise, there are significant challenges to the successful development, manufacturing, and delivery of multi-parameter genetically engineered T cell immunotherapies at a commercial scale.

Human induced pluripotent stem cells (hiPSCs) offer a practical and renewable source of engineered CAR-T cells. A novel platform has been established for multi-gene locus-specific engineering of hiPSCs, creating characterized master cell banks that can be used to generate engineered cytotoxic T cells through a stage-specific differentiation process.

FT819 is the first pre-clinical candidate of an off-the-shelf hiPSC-derived CAR-T cell product. It was developed by combining reprogramming of peripheral blood T cells with targeted insertion of a CD19 CAR into the T cell receptor α (TRAC) locus, resulting in a clonal TRAC-targeted CAR-expressing master hiPSC line. This line demonstrated pluripotency and bi-allelic disruption of the TRAC locus. During differentiation, the hiPSC line efficiently converted into CD34 positive cells, which further differentiated into CD8 positive cells with uniform CAR expression and no TCR expression, thus avoiding graft-versus-host disease (GvHD).

FT819 has shown to elicit a potent cytotoxic T lymphocyte response in vitro, with production of effector cytokines, degranulation, proliferation, and upregulation of activation markers. It targets tumors in an antigen-specific manner, as evidenced by its ability to lyse CD19+ but not CD19- tumor cell lines. The data suggest that FT819 could provide a safe and effective off-the-shelf cytotoxic CAR-T cell product, produced through a renewable and highly reproducible process similar to biopharmaceutical manufacturing.