Evaluation of amantadine in chronic hepatitis C: a meta-analysis

Background/Aims The benefit of amantadine combination therapy, either with interferon (IFN) alone (double therapy) or with ribavirin and IFN (triple therapy) is unknown. Methods We analyzed the effect of amantadine on the end-of-treatment virological response and the sustained response using meta-analysis of 31 randomized controlled trials. Results Overall analysis revealed a significant effect of amantadine. Triple therapy was the best regimen for improving the sustained response (mean difference: 8.4%, 95% CI: 2.4–13.8%, P=0.002). In subgroup analysis, amantadine did not have a significant effect upon naive patients or relapsers. In non-responders, combination therapy with amantadine was associated with a significant effect on the sustained response (mean difference: 8.3%, 95% CI: 1.9–14.6%, P=0.01). In sensitivity analysis, double therapy did not improve virological responses. Conversely, triple therapy tended to improve the end-of-treatment virological response and was associated with a significant effect upon the sustained response (mean difference: 12.7%, 95% CI: 3.8–21.6%, P=0.005). Conclusions Combination therapy with amantadine is of no effect upon naive patients or relapsers. In non-responders, triple therapy with amantadine improved the sustained response. New randomized controlled trials are required to confirm this meta-analysis.