Low dose alpha interferon treatment in chronic hepatitis B virus infection

Systematic review of the literature on comparative effectiveness of antiviral treatments for chronic hepatitis B infection

OBJECTIVES

To evaluate the comparative effectiveness of antiviral drugs in adults with chronic hepatitis B monoinfection for evidence-based decision-making.

METHODS

A systematic review of randomized controlled clinical trials (RCTs) published in English. Results after interferon and nucleos(t)ides analog therapies were synthesized with random-effects meta-analyses and number needed to treat (NNT).

RESULTS

Despite sustained improvements in selected biomarkers, no one drug regimen improved all intermediate outcomes. In 16 underpowered RCTs, drug treatments did not reduce mortality, liver cancer, or cirrhosis. Sustained HBV DNA clearance was achieved in one patient when two were treated with adefovir (NNT from 1 RCT=2 95%CI 1;2) or interferon alpha-2b (NNT from 2 RCTs=2 95%CI 2;4), 13 with lamivudine (NNT from 1 RCT=13 95%CI 7;1000), and 11 with peginterferon alpha-2a vs. lamivudine (NNT from 1 RCT=11 95%CI 7;25). Sustained HBeAg seroconversion was achieved in one patient when eight were treated with interferon alpha-2b (NNT from 2 RCTs=8 95%CI 5;33) or 10--with peginterferon alpha-2b vs. interferon alpha-2b (NNT from 1 RCT=10 95%CI 5;1000). Greater benefits and safety after entecavir vs. lamivudine or pegylated interferon alpha-2b vs. interferon alpha-2b require future investigation of clinical outcomes. Adverse events were common and more frequent after interferon. Treatment utilization for adverse effects is unknown.

CONCLUSIONS

Individual clinical decisions should rely on comparative effectiveness and absolute rates of intermediate outcomes and adverse events. Future research should clarify the relationship of intermediate and clinical outcomes and cost-effectiveness of drugs for evidence-based policy and clinical decisions.

Effect of conventional interferon-α in patients with HBeAg-positive chronic hepatitis B: a systematic review and meta-analysis

BACKGROUND

Although a few studies have tested the effect of interferon-α on chronic hepatitis B, its treatment effect remains uncertain, and the association of treatment effect with intervention characteristics has not been thoroughly explored. This study examined the effect of IFN-α in patients with HBeAg-positive chronic hepatitis B, and investigated the characteristics associated with treatment effect.

METHODS

We searched MEDLINE, Scientific Citation Index, Current Content Connect, Cochrane Controlled Trial Register, and Chinese Biomedical Database, all up to 15 September 2009. We included randomized trials comparing IFN-α to placebo, no treatment, or standard care (SC) in patients with HBeAg-positive chronic hepatitis B. Two reviewers assessed the risk of bias and extracted data, independently and in duplicate. We conducted meta-analyses of the included studies, and subgroup analyses to examine the association of pre-specified characteristics (eg, dose, treatment duration) with treatment effect.

RESULTS

A total of 31 randomized controlled trials, involving 2164 patients, were included. The risk of bias varied across studies. Compared with placebo, no treatment, or SC, IFN-α improved loss of HBeAg (OR 2.36, 95% CI 1.83 to 3.04), HBV DNA undetectability (OR 2.04, 95% CI 1.28 to 3.32), HBeAg seroconversion (OR 1.82, 95% CI 1.26 to 2.62), ALT normalization (OR 1.24, 95% CI 1.01 to 1.56), and loss of HBsAg (OR 2.45, 95% CI 1.22 to 4.91). Treatment effects differed in high versus low dose, and long versus short duration of IFN-α. The effect of high dose IFN-α (OR 3.28, 95% CI 2.31 to 4.66) is statistically larger than that of low dose IFN-α (OR 1.58, 95% CI 1.10 to 2.28) on loss of HBeAg (interaction P = 0.017), and longer IFN-α treatment durations produce greater effects (OR 3.28, 95% CI 2.16 to 5.00) than do shorter durations (OR 1.94, 95% CI 0.42 to 2.66, interaction P = 0.038). High dose IFN-α had a significant effect on HBV DNA undetectability (OR 2.80, 95% CI 2.03 to 3.86), while low dose IFN-α did not (OR 0.93, 95% CI 0.61 to 1.41, interaction P = 0.01); longer treatments significantly improved HBV DNA undetectability (OR 2.58, 95% CI 1.62 to 4.12), but shorter durations did not (OR 1.28, 95% CI 0.83 to 1.97, interaction P = 0.024).

CONCLUSIONS

IFN-α can improve serological, biomedical, and virological response. Higher doses and prolonged treatments appear to have larger treatment benefits than lower doses and shorter treatments. However, the increased adverse reactions and costs associated with higher doses and prolonged treatment warrant caution in applying these results.

Treatment of hepatitis B with interferon and combination therapy

Pegylated interferon alpha-a (40 kDa) has recently been shown to be superior to conventional interferon. Furthermore, in a pilot study, pegylated interferon alpha-2b together with lamivudine was superior to lamivudine monotherapy. Therefore, the pegylated interferons alone or in combination with antiviral agents are likely to be the treatment of the future. Selecting patients for treatment and knowing when to treat them is as important as knowing which medicine to treat them with.