Freeburg and Chafamo et al. performed longitudinal single-cell profiling of CSF and tumors from 18 patients with recurrent GBM treated with a single intracerebroventricular dose of bivalent EGFR-IL13Rα2 CAR T cells. CAR T cells peaked at 7 days and showed increased cytotoxicity and exhaustion in CSF. Endogenous cytotoxic NK cells, Tregs, and “scavenger” myeloid cells also increased dose-dependently. Responses correlated with increased CD56dimCD16+ NK cells, while Treg expansion and a high baseline number of immunosuppressive myeloid cells correlated with non-response, emphasizing the endogenous immune system’s role in CAR T cell efficacy.

Contributed by Katherine Turner

ABSTRACT: Glioblastoma (GBM) is the most common primary malignant brain tumor in adults, with a median survival of under 15 months and no effective treatment after recurrence. A recent phase 1 trial of intracerebroventricular bivalent chimeric antigen receptor (CAR) T cells in recurrent GBM, registered at ClinicalTrials.gov (NCT05168423), showed promising responses, including tumor reduction and prolonged survival. However, relapse remains common. We performed in-depth profiling of longitudinal cerebrospinal fluid (CSF) and tumor samples from responders and non-responders to characterize immune dynamics following infusion. Our study reveals that, although CAR T cells activate post infusion across all patients, outcomes were defined by divergent remodeling of the endogenous immune landscape. Cytotoxic natural killer cell expansion characterized responders, whereas regulatory T cell expansion and abundant baseline immunosuppressive scavenger myeloid cells characterized non-responders. These findings indicate that host immune cells play a critical role in CAR T cell therapy for GBM, suggesting that combinatorial strategies modulating the endogenous immune compartment could improve next-generation treatments.

Author Info: (1) Cancer Biology Department, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA. (2) Cancer Biology Department, Perelman School of Medicin e at the University of Pennsylvania, Philadelphia, PA 19104, USA. (3) Cancer Biology Department, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA. (4) Department of Pathology, Case Western Reserve University School of Medicine and Case Comprehensive Cancer Center, Cleveland, OH, USA. (5) Cancer Biology Department, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA. (6) Cancer Biology Department, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA. (7) Department of Neurosurgery, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; Center for Cellular Immunotherapies, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; GBM Translational Center of Excellence, Abramson Cancer Center, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; Cell and Molecular Biology Graduate Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA. (8) Department of Pathology, Case Western Reserve University School of Medicine and Case Comprehensive Cancer Center, Cleveland, OH, USA. (9) Department of Neurosurgery, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; Center for Cellular Immunotherapies, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; GBM Translational Center of Excellence, Abramson Cancer Center, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA. (10) Neuroscience Graduate Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA. (11) Department of Neuroscience and Mahoney Institute for Neurosciences, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA. (12) Department of Neurosurgery, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; Center for Cellular Immunotherapies, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; GBM Translational Center of Excellence, Abramson Cancer Center, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA. (13) Department of Neurosurgery, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; Center for Cellular Immunotherapies, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; GBM Translational Center of Excellence, Abramson Cancer Center, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA. (14) Department of Neurosurgery, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA. (15) Neuroscience Graduate Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA. (16) Department of Biology, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA, USA. (17) UniversitŽ Paris CitŽ, INSERM, PARCC, Paris, France; Department of Immunology, APHP, H™pital EuropŽen Georges Pompidou (HEGP)-H™pital Necker, Paris, France. (18) Centre de Recherche des Cordeliers, Sorbonne UniversitŽ, INSERM, UniversitŽ Paris CitŽ, 75006 Paris, France. (19) CellAction, Center for Cancer Immunotherapy, INSERM U932, Institut Curie, Saint-Cloud, France. (20) Department of Neurosurgery, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; Center for Cellular Immunotherapies, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; GBM Translational Center of Excellence, Abramson Cancer Center, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA. (21) Department of Neurosurgery, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; Center for Cellular Immunotherapies, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; GBM Translational Center of Excellence, Abramson Cancer Center, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA. (22) Clinical Immunology Laboratory, Institut Curie, Paris, France. (23) Institut Curie, PSL University, INSERM U932, Immunity and Cancer, 75005 Paris, France. (24) Department of Translational Research, PSL University, Institut Curie, Paris, France; INSERM U1330, PSL University, Institut Curie Research Center, Paris, France. (25) CellAction, Center for Cancer Immunotherapy, INSERM U932, Institut Curie, Saint-Cloud, France. (26) CellAction, Center for Cancer Immunotherapy, INSERM U932, Institut Curie, Saint-Cloud, France; Clinical Hematology Unit, Institut Curie, Saint-Cloud, France. (27) Departments of Dermatology and Pathology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA. (28) Department of Dermatology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA. (29) Kite, a Gilead Company, Santa Monica, CA, USA. (30) Comparative Pathology Core, Department of Pathobiology, University of Pennsylvania, School of Veterinary Medicine, Philadelphia, PA, USA. (31) Comparative Pathology Core, Department of Pathobiology, University of Pennsylvania, School of Veterinary Medicine, Philadelphia, PA, USA. (32) Comparative Pathology Core, Department of Pathobiology, University of Pennsylvania, School of Veterinary Medicine, Philadelphia, PA, USA. (33) Center for Cellular Immunotherapies, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Medicine, Division of Hematology and Oncology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA. (34) Center for Cellular Immunotherapies, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Medicine, Division of Hematology and Oncology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA. (35) Center for Cellular Immunotherapies, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Medicine, Division of Hematology and Oncology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA. (36) Department of Neuroscience and Mahoney Institute for Neurosciences, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA; Department of Cell and Developmental Biology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA; Department of Psychiatry, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA; Institute for Regenerative Medicine, University of Pennsylvania, Philadelphia, PA, USA. (37) Centre de Recherche des Cordeliers, Sorbonne UniversitŽ, INSERM, UniversitŽ Paris CitŽ, 75006 Paris, France; ƒquipe labellisŽe Ligue Contre le Cancer, Centre de Recherche des Cordeliers, 15 rue de l'Žcole de mŽdecine, 75006 Paris, France. (38) Centre de Recherche des Cordeliers, Sorbonne UniversitŽ, INSERM, UniversitŽ Paris CitŽ, 75006 Paris, France; ƒquipe labellisŽe Ligue Contre le Cancer, Centre de Recherche des Cordeliers, 15 rue de l'Žcole de mŽdecine, 75006 Paris, France. (39) UniversitŽ Paris CitŽ, INSERM, PARCC, Paris, France; Department of Immunology, APHP, H™pital EuropŽen Georges Pompidou (HEGP)-H™pital Necker, Paris, France. (40) Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA; Institute for Immunology and Immune Health, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA. (41) Institut Curie, PSL University, INSERM U932, Immunity and Cancer, 75005 Paris, France. (42) Center for Cellular Immunotherapies, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Microbiology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA; Department of Pathology and Laboratory Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA; Parker Institute for Cancer Immunotherapy, University of Pennsylvania, Philadelphia, PA, USA. (43) GBM Translational Center of Excellence, Abramson Cancer Center, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Pathology and Laboratory Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA. (44) Department of Neuroscience and Mahoney Institute for Neurosciences, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA; Department of Neurosurgery, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; GBM Translational Center of Excellence, Abramson Cancer Center, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; Institute for Regenerative Medicine, University of Pennsylvania, Philadelphia, PA, USA; Epigenetics Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA. (45) Department of Pathology, Case Western Reserve University School of Medicine and Case Comprehensive Cancer Center, Cleveland, OH, USA; Department of Pathology, University Hospitals Cleveland Medical Center, Cleveland, OH, USA. (46) GBM Translational Center of Excellence, Abramson Cancer Center, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Medicine, Division of Hematology and Oncology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA. (47) Department of Neurosurgery, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; Center for Cellular Immunotherapies, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; GBM Translational Center of Excellence, Abramson Cancer Center, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; Parker Institute for Cancer Immunotherapy, University of Pennsylvania, Philadelphia, PA, USA. (48) Department of Neurosurgery, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; Center for Cellular Immunotherapies, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; GBM Translational Center of Excellence, Abramson Cancer Center, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA. Electronic address: binderz@pennmedicine.upenn.edu. (49) Department of Neurosurgery, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; UniversitŽ Paris CitŽ, INSERM, PARCC, Paris, France; Clinical Laboratory, H™pital Foch, Suresnes, France. Electronic address: c.alanio@hopital-foch.com. (50) Cancer Biology Department, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Neurosurgery, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; Center for Cellular Immunotherapies, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA. Electronic address: dana.silverbush@pennmedicine.upenn.edu.