Advancing treatment and understanding of immunotherapy in glioblastoma

SUMMARY/ABSTRACT Immunotherapy holds great promise for the treatment of glioblastoma; still, certain characteristics of glioblastoma present inherent therapeutic challenges.

Herein, two experienced interdisciplinary laboratory and clinical teams at UCSFs Helen Diller Family Comprehensive Cancer Center and Northwestern University's Robert H. Lurie Comprehensive Cancer Center join efforts to develop innovative immunotherapy approaches against glioblastoma.

This proposal leverages industry and institutional support to address three specific objectives: 1) to improve our understanding of the role of immunotherapy approaches in glioblastoma; 2) to improve our understanding of how to overcome the limitation the blood brain barrier and 3) to develop innovative immunotherapy treatments for glioblastoma, with associated early clinical trials focused on patients suffering from recurrent glioblastoma.

Project 1, coordinated from Northwestern, will build on the team's preclinical results in mouse brain tumor models demonstrating an immunomodulatory and sensitization effect when immune checkpoint inhibitor therapy is preceded by a immunogenic dose of doxorubicin, an effect that can be further enhanced by ultrasound-based BBB opening.

Support by innovative biotech companies (Agenus, AstraZeneca, Carthera) provide drugs or devices for preclinical and clinical investigation as well as specific expertise, assays and technology for investigations at both institutions, making this collaboration a very powerful consortium.

The ensuing clinical trial will investigate the novel anti-PD1 checkpoint inhibitor balstilimab in conjunction with doxorubicin, with and without sonication for BBB opening.

By administration of immune therapy prior to surgery (induction therapy, neoadjuvant treatment) the immune effect enables us to evaluate in vivo immune response in the resected brain tissue.

We have previously identified pERk/MAPK activation as a biomarker for benefit from anti-PD1 treatment in recurrent glioblastoma; this and other markers will be explored furthermore.

Four prospectively treated cohorts will be treated with and without induction therapy, and with and without BBB opening. Translational endpoints include immune response (tumor tissue, peripheral) and drug tissue concentration.

Project 2, coordinated from UCSF, is a study based on the exciting novel synthetic Notch ?synNotch? receptor CART system and pioneering T cell circuits that recognize tumor cells based on a ?prime-and-kill? strategy.

In this system, the first antigen, which is expressed exclusively on GBM cells (EGFRvIII), primes the T cells to induce expression of a CAR that recognizes IL-13R?2 and EphA2, thereby eradicating GBM cells expressing either EphA2 or IL-13?2.

Project 2's team hypothesizes that synNotch CART cells can revolutionize the CART therapy for glioblastoma by overcoming the challenges of off-tumor toxicity, antigen heterogeneity, and CART cell exhaustion.

Thus, these synNotch-CART cells are hypothesized to be significantly more efficacious than conventional, constitutively expressed IL-13R?2/EphA2 CART cells.

Investigators will optimize the efficacy of the lead agent and test this hypothesis in the first in human clinical trial of this new class of agents in glioblastoma patients.

This U19 proposal also has set aside funds for support of the distinctly important trans-GTN pilot projects, and for two cores (Administrative, Immune Monitoring & Biospecimen) that will support the efforts of the two projects.

By addressing the overall specific objectives described, the research proposed in this U19 application has a high likelihood of changing the way immunotherapy is understood and utilized in glioblastoma.

The innovative research described in this proposal will take advantage of the exceptional resources assembled by the well- established, collaborative group of clinical and basic scientists at UCSF and Northwestern.