Glioblastoma is the most common malignant primary brain tumor. Despite standard-of-care treatment, consisting of maximal surgical resection followed by chemoradiation, both morbidity and mortality associated with this disease remain very poor. Therefore, there is an urgent need for more efficacious and well tolerated therapies. Advancing knowledge of the intricate interplay between malignant gliomas and the immune system, coupled with the recent launch of immunotherapy research for other cancers, has led to a veritable increase in immunotherapy investigation for glioblastoma and other malignant gliomas. This clinical review highlights the recent breakthroughs in cancer immunotherapy and the complex correlation of the immune system with primary brain tumors, with special attention to multiple immunotherapy modalities currently being investigated for malignant glioma, including peptide vaccines, dendritic cell vaccines, oncolytic viruses, chimeric T-cell receptors, and checkpoint inhibitors. Cancer 2017;123:734-50. © 2016 American Cancer Society.

Immune checkpoint inhibitors have improved patient survival outcomes in a variety of advanced malignancies. However, they can cause a number of immune-related adverse effects (irAEs) through lymphocyte dysregulation. Central nervous system (CNS) irAEs are rare, but as the number of indications for checkpoint inhibitors increases, there has been emergence of CNS immune-mediated disease among cancer patients. Given the relatively recent recognition of checkpoint inhibitor CNS irAEs, there is no standard treatment, and prognosis is variable. Therefore, there is a great need for further study of checkpoint inhibitor-induced CNS irAEs. Here, we present two unique cases of nivolumab-induced autoimmune encephalitis in patients with non-small cell lung cancer and review the available literature.

Median survival for glioblastoma (GBM) remains <15 months. Human cytomegalovirus (CMV) antigens have been identified in GBM but not normal brain, providing an unparalleled opportunity to subvert CMV antigens as tumor-specific immunotherapy targets. A recent trial in recurrent GBM patients demonstrated the potential clinical benefit of adoptive T-cell therapy (ATCT) of CMV phosphoprotein 65 (pp65)-specific T cells. However, ex vivo analyses from this study found no change in the capacity of CMV pp65-specific T cells to gain multiple effector functions or polyfunctionality, which has been associated with superior antitumor efficacy. Previous studies have shown that dendritic cells (DC) could further enhance tumor-specific CD8 þ T-cell polyfunctionality in vivo when administered as a vaccine. Therefore, we hypothesized that vaccination with CMV pp65 RNA-loaded DCs would enhance the frequency of polyfunctional CMV pp65-specific CD8 þ T cells after ATCT. Here, we report prospective results of a pilot trial in which 22 patients with newly diagnosed GBM were initially enrolled, of which 17 patients were randomized to receive CMV pp65-specific T cells with CMV-DC vaccination (CMV-ATCT-DC) or saline (CMV-ATCT-saline). Patients who received CMV-ATCT-DC vaccination experienced a significant increase in the overall frequencies of IFNg þ , TNFa þ , and CCL3 þ polyfunctional, CMV-specific CD8 þ T cells. These increases in polyfunctional CMV-specific CD8 þ T cells correlated (R ¼ 0.7371, P ¼ 0.0369) with overall survival, although we cannot conclude this was causally related. Our data implicate polyfunctional T-cell responses as a potential biomarker for effective antitumor immunotherapy and support a formal assessment of this combination approach in a larger randomized study. Significance: A randomized pilot trial in patients with GBM implicates polyfunctional T-cell responses as a biomarker for effective antitumor immunotherapy. Cancer Res; 78(1); 256-64.Ó2017 AACR.