The prognosis for patients with newly diagnosed glioblastoma receiving bevacizumab combination therapy: a meta-analysis

Background: A combination of temozolomide (TMZ) and radiotherapy and subsequent adjuvant chemotherapy is the gold standard of treatment for glioblastoma (GB). Bevacizumab (BEV), a humanized monoclonal antibody that blocks the effects of vascular endothelial growth factor A, has produced impressive response rates for recurrent GB and has been approved as second-line therapy. The efficacy and safety of BEV in newly diagnosed GB are not known.

Aim: This systematic meta-analysis was undertaken to evaluate the value of combination therapy involving BEV in newly diagnosed GB.

Methods: Electronic databases were searched for eligible literature up to October 2017. Randomized controlled trials assessing the efficacy and safety of BEV in patients with newly diagnosed GB were included, of which the main outcomes were progression-free survival (PFS), overall survival (OS), and adverse events (AEs). All the data were pooled with the corresponding 95% confidence intervals (CIs) using RevMan software. Sensitivity analyses and heterogeneity were quantitatively evaluated.

Results: A total of six randomized controlled trials were included in this analysis. The experimental BEV group had significantly improved the overall PFS (OR =0.46, 95% CI =0.26-0.81, P=0.007), as well as PFS at 6 months (OR =3.47, 95% CI =2.85-4.22, P<0.00001) and PFS at 12 months (OR =2.02, 95% CI =1.66-2.46, P<0.00001), respectively. However, there were no significant differences in PFS at 24 months with BEV (OR =0.95, 95% CI =0.61-1.48, P=0.82). OS at 6 months (P=0.07) and 24 months (P=0.07) was not significantly improved with BEV in patients with newly diagnosed GB. However, the meta-analysis on the OS at 12 months showed differences with BEV (OR =1.24, 95% CI =1.03-1.50, P=0.02).

Conclusion: Our study indicates that addition of BEV for newly diagnosed GB resulted in a superior PFS rate. However, the combination therapy involving BEV did not improve OS. Future investigations are needed to analyze whether BEV helps improve OS efficacy.