Bevacizumab in Japanese patients with malignant glioma: from basic research to clinical trial

An antiangiogenic approach is especially suitable for the treatment of malignant gliomas. Recently, two large clinical trials in newly diagnosed glioblastoma (the Avastin in Glioblastoma study and Radiation Therapy Oncology Group 0825 study) showed a 3- to 4-month prolongation of progression-free survival (PFS) with bevacizumab, but no significant effect on overall survival (OS). Japan is the first, and so far only, country to approve the use of bevacizumab in newly diagnosed glioblastoma in combination with radiotherapy and temozolomide chemotherapy. The drug is also approved for use as monotherapy for recurrent glioblastoma and certain other types of high-grade glioma after previous therapy. The effectiveness of bevacizumab on Japanese malignant glioma patients was reviewed. The Phase II clinical trial demonstrated that the PFS with bevacizumab alone was 34% at 6 months and 3.3 months at median for 32 patients with recurrent malignant gliomas. In the Avastin in Glioblastoma study, 44 Japanese patients were registered from Japan. PFS and OS for bevacizumab combined with standard temozolomide and radiotherapy were 12.2 months and 29.2 months at median, respectively, for the patients with newly diagnosed glioblastoma. PFS and OS tended to be longer for those treated with bevacizumab than for those not treated with the drug. In addition, biomarkers of bevacizumab effectiveness were investigated in Japanese patients. Vascular endothelial growth factor concentration, matrix metalloproteinase 9 activities in urine, and apparent diffusion coefficient values on magnetic resonance imaging may be biomarkers that predict patient prognosis. Finally, novel experiments for vascular endothelial growth factor antibody action were described; these include the induction of glioma cell apoptosis, an antibody treatment failure model, and a study of the synergistic effect with chemotherapeutic agents.