What is the place of bevacizumab and irinotecan in the treatment of glioblastoma and other malignant gliomas?

Abstract

To critically assess the role of irinotecan (Camptosar, CPT-11) and bevacizumab (Avastin) as a new treatment for glioblastoma and other malignant gliomas (anaplastic forms of astrocytomas and oligodendrogliomas). Two prospective phase II trials of bevacizumab and irinotecan have been reported. The observed high response rates (30-60%) had never been seen in this disease before. Gains in progression-free survival and overall survival (OS) were less impressive (6-month progression-free survival 30-50%; median OS: 9-10 months), but are still superior to historical controls. Bevacizumab is a welcome new weapon in the treatment of malignant gliomas and should be favored as a salvage treatment over cytotoxic chemotherapy for recurrent disease. However, survival results remain far from satisfactory. Once failure to treatment with bevacizumab is diagnosed by conventional radiographic methods, most patients experience rapid deterioration and die shortly afterward. New methods and radiographic criteria for detecting disease progression are needed. Patients willing to explore new treatment strategies through participation in clinical trials should do so prior to starting bevacizumab, as this may not be an option once treatment fails. Cost-effectiveness of bevacizumab in gliomas deserves further investigation. The role of irinotecan in this combination remains unclear. At this time, bevacizumab should only be used in newly diagnosed malignant gliomas in the setting of a clinical trial.