Bevacizumab may improve quality of life, but not overall survival in glioblastoma: an epidemiological study

Abstract

Background

The vascular endothelial growth factor antibody bevacizumab (Avastin®), received approval for the treatment of recurrent glioblastoma in many countries including the US and Switzerland, but not the European Union, in 2009. Here we explored the hypothesis that the approval of bevacizumab improved outcome with glioblastoma on a population level.

Patients and methods

The prognostic significance of epidemiological, molecular genetic, and clinical data including treatment for glioblastoma patients diagnosed from 2010-2014 in the Canton of Zurich, Switzerland, was retrospectively analyzed using log rank test and Cox proportional hazards models. Data were compared to data for the years 2005-2009.

Results

310 glioblastoma patients were identified in the years 2010-2014. Median overall survival (OS) was 13.5 months for patients with known isocitrate dehydrogenase (IDH) wildtype (wt) (IDH1^R132H-non-mutant) tumors (N=248), compared with 11.3 months for IDH wt patients (P=0.761) before (2005-2009). In the IDH wt cohort bevacizumab use at any time increased from 19% in 2005-2009 to 49% in 2010-2014. Multivariate analysis did not identify bevacizumab exposure at any time to be associated with survival. Yet, upon second-line treatment, baseline doses of corticosteroids were reduced by more than half in 83% of patients on bevacizumab compared with 48% of the patients treated with bevacizumab-free regimens (P=0.007).

Conclusion

This epidemiological study of a small, but clinically well annotated patient cohort fails to support the assumption that the strong increase of bevacizumab use since 2010 improved survival in glioblastoma, although clinical benefit associated with decreased steroid use may have been achieved.