Physical Poster + E-Poster Presentation 34th Lorne Cancer Conference 2022

Novel EGFRvIII-specific murine CAR T cells eliminate glioblastoma tumours and provides an opportunity for further engineering (#102)

Rebecca C Abbott 1 2 , Daniel J Verdon 1 , Fiona M Gracey 3 , Hannah E Hughes-Parry 1 2 , Melinda Iliopoulos 1 , Kathy A Watson 1 , Matthias Mulazzani 1 , Kylie Luong 1 , Colleen D'Arcy 4 , Lucy C Sullivan 5 , Ben R Kiefel 3 , Ryan S Cross 1 , Misty R Jenkins 1 2 6
  1. Department of Immunology, The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
  2. Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
  3. Myrio Therapeutics, Scoresby, Victoria, Australia
  4. Anatomical Pathology, Royal Children's Hospital, Parkville, Victoria, Australia
  5. Department of Microbiology and Immunology, Peter Doherty Institute, Parkville, Victoria, Australia
  6. Institute for Molecular Science, La Trobe University, Bundoora, Victoria, Australia

Glioblastoma is a highly malignant brain tumour which accounts for approximately 60% of all adult brain cancer diagnosis and has a five-year survival rate of 5%1. Chimeric Antigen Receptor (CAR) T cell therapy is a form of immunotherapy which provides a patient’s immune cells with a synthetic receptor, enabling recognition and lysis of malignant cells. We have developed a novel pipeline using a human Retained Display (ReD) antibody platform to screen for single chain binders (scFvs) to the glioblastoma tumour specific mutation; EGFRvIII. We identified a high affinity binder (designated GCT02) and designed a second-generation CAR2. We characterised the function of this CAR in vitro and in vivo using an orthotopic xenograft model of glioblastoma. The GCT02 CAR generally secreted lower quantities of evaluated cytokines, with comparable cytotoxic function to the industry benchmark EGFRvIII binder being currently used in clinical trials. In vivo modelling demonstrated a single intravenously delivered dose of GCT02 CAR T cells to be sufficient to eliminate implanted glioblastoma tumour cells two weeks post treatment, confirmed by pathological analysis2.

However clinically, CAR T cell therapy for solid tumours has not resulted in the same success as haematological malignancies3-7. This can be attributed to factors including the immunosuppressive tumour microenvironment, significant intratumoural and interpersonal tumour heterogeneity and the variation and kinetic changes in cell surface antigen expression. Consequently, new therapies are being designed which utilise genetic engineering to address these considerations and enhance efficacy. Logic gated genetic circuits have been previously developed to induce the production of selected anti-tumour molecules within the tumour microenvironment, with the benefit of limiting systemic expression8,9. We are now investigating the incorporation of such synthetic circuitry into our CAR T cell systems. 

  1. Brain and Other Central Nervous System Cancers. In. Canberra: Australian Institute of Health and Welfare; 2017: 80.
  2. Abbott RC, Verdon DJ, Gracey FM, Hughes-Parry HE, Iliopoulos M, Watson KA, Mulazzani M, Luong K, D'Arcy C, Sullivan LC et al. (2021) Novel high-affinity EGFRvIII-specific chimeric antigen receptor T cells effectively eliminate human glioblastoma. Clin Transl Immunology. 10(5):e1283
  3. Maude SL, Frey N, Shaw PA, Aplenc R, Barrett DM, Bunin NJ, Chew A, Gonzalez VE, Zheng Z, Lacey SF et al. (2014) Chimeric Antigen Receptor T Cells for Sustained Remissions in Leukemia. New England Journal of Medicine. 371(16):1507-1517.
  4. O'Rourke DM, Nasrallah MP, Desai A, Melenhorst JJ, Mansfield K, Morrissette JJD, Martinez-Lage M, Brem S, Maloney E, Shen A et al. (2017) A single dose of peripherally infused EGFRvIII-directed CAR T cells mediates antigen loss and induces adaptive resistance in patients with recurrent glioblastoma. Science translational medicine. 9(399).
  5. Goff SL, Morgan RA, Yang JC, Sherry RM, Robbins PF, Restifo NP, Feldman SA, Lu YC, Lu L, Zheng Z et al. (2019) Pilot Trial of Adoptive Transfer of Chimeric Antigen Receptor-transduced T Cells Targeting EGFRvIII in Patients With Glioblastoma. J Immunother. 42(4):126-135.
  6. Brown CE, Alizadeh D, Starr R, Weng L, Wagner JR, Naranjo A, Ostberg JR, Blanchard MS, Kilpatrick J, Simpson J et al. (2016) Regression of Glioblastoma after Chimeric Antigen Receptor T-Cell Therapy. The New England journal of medicine. 375(26):2561-2569.
  7. Ahmed N, Brawley V, Hegde M, Bielamowicz K, Kalra M, Landi D, Robertson C, Gray TL, Diouf O, Wakefield A et al. (2017) HER2-Specific Chimeric Antigen Receptor–Modified Virus-Specific T Cells for Progressive Glioblastoma: A Phase 1 Dose-Escalation Trial. JAMA oncology. 3(8):1094-1101.
  8. Roybal Kole T, Rupp Levi J, Morsut L, Walker Whitney J, McNally Krista A, Park Jason S, Lim Wendell A. (2016) Precision Tumor Recognition by T Cells With Combinatorial Antigen-Sensing Circuits. Cell. 164(4):770-779.
  9. Roybal KT, Williams JZ, Morsut L, Rupp LJ, Kolinko I, Choe JH, Walker WJ, McNally KA, Lim WA. (2016) Engineering T Cells with Customized Therapeutic Response Programs Using Synthetic Notch Receptors. Cell. 167(2):419-432.e416.