The efficacy of thymosin in the treatment of chronic hepatitis B virus infection: a meta-analysis

Background: Trials of thymosin treatment in chronic hepatitis B virus infection have been small and the results have been inconsistent. Aim: To conduct a meta-analysis to evaluate the efficacy of thymosin treatment in chronic hepatitis B virus infection. Methods: Randomized controlled trials comparing thymosin for over 24 weeks vs. placebo (or usual care) in the treatment of chronic hepatitis B virus infection were identified through MEDLINE, EMBASE and the Cochrane Register of Clinical Trials. Biochemical (normalization of transaminases) and virological (loss of hepatitis B virus DNA and hepatitis B e antigen) responses were analysed using the intention-to-treat method. The odds ratio was used to measure the magnitude of the efficacy. Results: Five trials (353 patients) were identified. The odds ratio (95% confidence interval) of the virological response of thymosin over placebo at the end of treatment, 6 months post-treatment and 12 months post-treatment were 0.56 (0.2-1.52), 1.67 (0.83-3.37) and 2.67 (1.25-5.68), respectively. There was an increasing trend of the virological response with time since the cessation of thymosin treatment (P = 0.02). There was no difference in the biochemical response between the thymosin and placebo groups at the end of treatment, 6 months post-treatment and 12 months post-treatment. Conclusions: Thymosin is effective in suppressing viral replication in chronic hepatitis B virus infection, but the effect is delayed until 12 months after the cessation of treatment.