IMMU-05. A PHASE I STUDY IN PROGRESS OF HEGFRVIII-CD3 BI-SCFV (BRITE) IN PATIENTS WITH WHO GRADE IV MALIGNANT GLIOMA

Abstract

Abstract INTRODUCTION Approximately 30% of glioblastomas harbor the tumor specific EGFRvIII mutation. hEGFRvIII-CD3 bi-scFv (Brain Bi-Specific T Cell Engager - BRiTE) is a novel bispecific antibody construct which can redirect a patient’s entire repertoire of T cells (TCR-agnostic) to specifically lyse EGFRvIII-positive tumor cells. Compared to CAR-T therapy, it offers a highly potent yet off-the-shelf approach for glioblastoma. BRiTE is now entering Phase I clinical trials (NCT04903795) and will be trialed as a monotherapy or with autologous T cell infusion. Migration of T cell binding macromolecules across the blood-brain barrier may be facilitated by activated T cells which adhere to the microvascular endothelium and enter the brain parenchyma. Concurrent administration of activated T cells could therefore enhance trafficking of BRiTE and other antibody-based macromolecules into the intracerebral compartment. HYPOTHESIS We hypothesize that treatment of EGFRvIII-positive WHO grade IV malignant glioma with BRiTE alone or with peripheral T-cell infusion is safe and can induce objective tumor shrinkage at tolerable doses. TRIAL DESIGN/OBJECTIVES A maximum of 18 patients with newly diagnosed or recurrent WHO grade IV malignant EGFRvIII+ glioma will be enrolled after undergoing standard of care treatment. The primary objective will be evaluating the safety of BRiTE alone and with autologous T cell infusion. Patients will receive a single BRiTE infusion, followed 14 days later by an infusion of activated autologous T cells and a second bolus BRiTE infusion. Dose escalation and de-escalation will be managed using a Bayesian optimal interval design. Secondary objectives will be to describe clinical benefit as determined by objective response rate per mRANO criteria, and to evaluate BRiTE pharmacokinetics in serum. CONCLUSION We describe a first-in-human trial of bispecific T cell engager therapy for glioblastoma. We also describe our novel approach for enhancing intracranial penetration of BRiTE using autologous T cell infusion.