CTIM-21. FIRST-IN-HUMAN PHASE I CLINICAL TRIAL USING 8R-70CAR T CELLS FOR NEWLY DIAGNOSED ADULT GLIOBLASTOMA

Abstract BACKGROUND To address the challenges of chimeric antigen receptor (CAR) T cell therapy in GBM, we utilized IL-8 release from tumor cells as a ‘GPS homing signal’ to enhance T-cell trafficking with a novel CD70-specific CAR design (8R-70CAR) that targets GBM. The 8R-70CAR offers several advantages: 1) Improved CAR T-cell trafficking, enhancing antitumor efficacy; 2) Reduced CD70, reshaping the tumor microenvironment (TME) and boosting endogenous immunity; 3) Utilized CD27 as the CAR, a co-stimulatory molecule that enhances T-cell functions; 4) Enabled CAR T cells to act as a sink to neutralize or remove IL-8, a pro-cancer chemokine, from the TME; and 5) Required only 120 ml of whole blood (not leukapheresis) for CAR T cell production. Preclinically, 8R-70CAR significantly enhanced CAR-T cell tumor migration and persistence, leading to complete tumor regression and sustained immune memory in a chemo/radiation/PD-1-blockade-resistant GBM model. These findings led to a phase-I trial (IMPACT trial: FDA-IND#23881, NCT05353530) using 8R-70CAR T cells for CD70 -positive newly diagnosed adult GBM. METHODS We aim to recruit 18 adult patients (3 + 3 dose-escalation design) with CD70-positive (>20%) tumors. The CAR T cells will be given intravenously after completing standard-of-care (SOC) therapy. Primary endpoints: Evaluate safety, tolerability, and dose-limiting toxicities (DLTs) to determine the maximum tolerated dose. Secondary endpoints: Assess preliminary efficacy. Immune monitoring and correlative studies will also be conducted. RESULTS To date, four patients have been enrolled in the IMPACT trial, with 2 eligible patients participating in treatment at dose level 1 (1x10^6/kg). One patient has completed treatment with 8R-70CAR T cells, experienced no DLTs, and is currently in follow-up. The remaining patient is under SOC therapy before receiving CAR T cell treatment. CONCLUSIONS This study aims to address current therapeutic gaps and offers options for implementing a novel CAR design for the development of a more effective therapeutic modality for GBM.