Survival analysis for valproic acid use in adult glioblastoma multiforme: A meta-analysis of individual patient data and a systematic review

Purpose: Glioblastoma multiforme (GBM) is the most lethal type of primary brain tumor, and patients that undergo the maximum tumor resection that is safely possible and standard radiochemotherapy only achieve a median survival time of 14.6 months. Several clinical studies have reported that valproic acid could prolong survival of GBM patients. However, the results of these studies are inconsistent. We examined relevant studies and conducted a meta-analysis to assess the effects of VPA on survival times and recurrence. Methods: A bibliographic search was performed in the EMBASE, MEDLINE, ClinicalTrials.gov and Cochrane Central Register of the Controlled Trials databases to identify potentially relevant articles or conference abstracts that investigated the effects of VPA on the outcome of glioma patients. Five observational studies were included. Results: Pooled estimates of the hazard ratio (HR) and 95% confidence intervals (CI) were calculated. Our meta-analysis confirmed the benefit of using VPA (HR, 0.56; 95% CI, 0.44-0.71). Sub-group analysis shows that patients treated with VPA had a hazard ratio of 0.74 with a 95% confidence interval of 0.59-0.94 vs. patients treated by other-AEDs and a hazard ratio of 0.66 with a 95% confidence interval of 0.52-0.84 vs. patients treated by administration of non-AEDs. No heterogeneity was observed in the subset analysis. Conclusion: The results of our study suggest that glioblastoma patients may experience prolonged survival due to VPA administration. Sub-analysis confirmed the benefit of VPA use compared to a non-AEDs group and an other-AEDs group. Further RCTs of this subject should be performed. (C) 2014 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.