The Current Landscape of Immune Checkpoint Blockade in Glioblastoma

Abstract

The glioblastoma tumor microenvironment is highly immunosuppressed. This immunosuppressive state is engineered by inhibitory molecules secreted by tumor cells that limit activation of immune effector cells, drive T-cell exhaustion, and enhance the immunosuppressive action of tumor-associated myeloid cells. Immunotherapeutic approaches have sought to combat glioblastoma microenvironment immunosuppression with agents such as immune checkpoint inhibitors. Although immune checkpoint blockade in glioblastoma has yielded disappointing results thus far, there is significant interest in the combination of immune checkpoint blockade with other approaches to enhance response.

Keywords: Cytotoxic T-lymphocyte–associated protein 4 (CTLA-4); Glioblastoma (GBM); Immune checkpoint blockade; Immune checkpoint inhibitor (ICI); Immunotherapy; Programmed cell death ligand 1 (PD-L1); Programmed cell death receptor 1 (PD-1).