Efficacy and Safety of Bevacizumab in Glioblastomas

Abstract

Glioblastoma multiforme (GBM) is a common and malignant primary brain tumor arising from glial precursors the survival of which is estimated to be about 14 months after diagnosis despite current standard care with radiotherapy, surgery, and chemotherapies. Therapeutic approaches were greatly improved in the last years; however, GBM still represents the most lethal subtype of glioma. Actually, it has been estimated that only about 3.4% of patients will survive at the most five years when obtaining the best outcome from treatment; however, this depends on tumor resistance, which is generally related to repairing radiation injury, and self- improving cell growth repair and survival. All GBMs recur after initial therapy, limiting patients � survival at 20-25% within 1 year after diagnosis of recurrent disease. Moreover, for recurrent GBM response rates are less than 10% (ranging from 5% to 9%), and progression free survival at 6-month (PFS-6) rates ranges between 9% and 28% (median 15%). The development of targeted therapy based on tumor vascular blockade led to the approval of bevacizumab for recurrent or progressive glioblastoma, since it was proven that this offers a new opportunity for patients suffering from this malignancy. Bevacizumab is a recombinant antivascular monoclonal antibody binding to circulating Vascular Endothelial Growth Factor (VEGF) preventing this cytokine from reaching its receptors (VEGFR1 and VEGFR2) on endothelium, resulting in an inhibition of cells proliferation and vessels sprouting. The aim of this review is to address bevacizumab mode of action in malignant gliomas and provide a summary on currently available data on efficacy and safety.