Trivalent CAR T-cells Overcome Interpatient Antigenic Variability in Glioblastoma

Abstract

Background

Glioblastoma (GBM) is the most common primary malignant brain cancer, and is currently incurable. Chimeric Antigen Receptor (CAR) T-cells have shown promise in GBM treatment. While we have shown that combinatorial targeting of two glioma antigens offsets antigen escape and enhances T-cell effector functions, the inter-patient variability in surface antigen expression between patients hinders the clinical impact of targeting two antigen pairs. This study addresses targeting 3 antigens using a single CAR T-cell product for broader application.

Methods

We analyzed the surface expression of 3 targetable glioma antigens (HER2, IL13Rα2 and EphA2) in 15 primary GBM samples. Accordingly, we created a trivalent T-cell product armed with three CAR molecules specific for these validated targets encoded by a single universal (U) tricistronic transgene (UCAR T-cells).

Results

Our data showed that co-targeting HER2, IL13Rα2 and EphA2 could overcome inter-patient variability by a tendency to capture near 100% of tumor cells in most tumors tested in this cohort. UCAR T-cells made from GBM patients' blood uniformly expressed all three CAR molecules with distinct antigen specificity. UCAR T-cells mediated robust immune synapses with tumor targets forming more polarized microtubule organizing centers (MTOC) and exhibited improved cytotoxicity and cytokine release over best monospecific and bispecific CAR T-cells per patient tumor profile. Lastly, low doses of UCAR T-cells controlled established autologous GBM patient derived xenografts (PDX) and improved survival of treated animals.

Conclusions

UCAR T-cells can overcome antigenic heterogeneity in GBM and lead to improved treatment outcomes.

from #ORL-AlexandrosSfakianakis via ola Kala on Inoreader http://ift.tt/2jzmQBQ