Abstract Glioblastoma (GBM) is the most common primary brain malignancy in adults, with a dismal prognosis despite an intensive standard of care. Recently, chimeric antigen receptor T-cell (CAR-T) therapy has shown promising outcomes in treating liquid malignancies. However, clinical trials targeting various tumor antigens in GBM failed to show durable clinical benefit. Though this may stem from various tumor-intrinsic immune evasion strategies typical of GBM, there has been little work investigating whether the problem lies in the quality of the CAR-T products treatment itself. Currently, CAR-T cells for clinical studies are produced in an autologous setting, where T-cells are extracted from patients, engineered ex-vivo, and then re-infused. However, peripheral T-cells taken from GBM patients have shown qualitative and functional deficits, which may contribute to suboptimal treatment outcomes. Thus, we aimed to explore whether CAR-Ts generated from GBM patients had any functional deficits in comparison to healthy donors, utilizing our previously validated CD133 CAR-T. In this study, we show pre-treatment exhaustion, poor tumor control, and reduced survival advantage in autologous, patient-derived CD133-targeting CAR-T cell products using an orthotopic xenograft model of human GBM. To address the functional and logistical considerations of autologous therapy, we also sought to generate an “off-the-shelf” allogeneic CD133 CAR-T. Using CRISPR gene editing technology, we generated TCR-knockout CAR-T cells with comparable pre-clinical efficacy to our healthy donor derived autologous models. Ultimately, this work highlights the need to reevaluate autologous CAR-T therapy for GBM and consider allogeneic approaches as biologically-informed therapeutic alternatives.

EXTH-51. ENHANCING GLIOBLASTOMA TREATMENT: ALLOGENEIC CAR-T CELLS OVERCOMES FUNCTIONAL DEFICITS OF PATIENT-DERIVED AUTOLOGOUS PRODUCTS