Chlorotoxin-directed CAR T cell therapy for recurrent glioblastoma: Interim clinical experience demonstrating feasibility and safety

Abstract

A challenge in treating glioblastoma (GBM) is its phenotypic heterogeneity between patients and within tumors. Chlorotoxin (CLTX), a peptide from scorpion venom, broadly binds glioma cells through a mechanism involving surface matrix metalloproteinase-2 (MMP-2). We previously developed chimeric antigen receptor (CAR) T cells incorporating CLTX as the GBM recognition domain. Here, we report interim clinical experience of a phase 1 trial evaluating intracavity/intratumoral (ICT) delivery of CLTX-CAR T cells in four patients with MMP-2-expressing recurrent GBM (NCT04214392), with the primary objectives of feasibility and safety. The therapy is well tolerated with no dose-limiting toxicities. Three of the four participants (75%) exhibit a best response of stable disease. CLTX-CAR T cells are detected in the tumor cavity fluid and at lower levels in the blood. Human anti-CAR antibody assays do not detect humoral immunogenicity against the CLTX-CAR. These observations support further clinical evaluation of CLTX-CAR therapy.

Keywords: T cells; chimeric antigen receptor; chlorotoxin; immunotherapy; phase 1 clinical trial.