[Treatment of the glioma microenvironment]

Therapeutic concepts for malignant gliomas increasingly target the genetically non-transformed tumor stroma rather than the tumor cells themselves. There are two particular compartments of the tumor stroma which are currently tackled: the vascular compartment by using antiangiogenic treatment with the aim of vascular normalization and the immune compartment with the aim of enhancing or inducing anti-tumor immunity. Although the vascular endothelial growth factor (VEGF) A antibody bevacizumab has not been approved for the treatment of malignant glioma in European countries, there is evidence from smaller trials of biological efficacy particularly in recurrent disease and the results of a large European phase III study testing the clinical efficacy are currently expected. Immunotherapies are on the verge of entering the clinical arena with the first randomized phase III clinical trials having already been completed. In these studies, active vaccination and checkpoint inhibitors which are approved for other tumor entities are being tested. This article provides an overview on the current antiangiogenic and immunological therapies for gliomas, summarizes the results of clinical trials and discusses further developments.