Treatment of chronic hepatitis B with recombinant interferon alpha versus recombinant interferon alpha plus levamisole

Effects of oral levamisole as an adjuvant to hepatitis B vaccine in adults with end-stage renal disease: a meta-analysis of controlled clinical trials

BACKGROUND

Many patients receiving long-term dialysis do not produce protective antibodies to hepatitis B virus (HBV) surface antigen (HBsAg) after HBV vaccination. The results from several studies have suggested benefit of oral levamisole as an adjuvant to HBV vaccination in patients with end-stage renal disease (ESRD). However, reliable information is still lacking.

OBJECTIVE

This meta-analysis assessed the efficacy and safety profile of oral levamisole as an adjuvant to HBV vaccine in patients with ESRD.

METHODS

This meta-analysis included prospective controlled clinical trials identified using literature searches of MEDLINE, SCOPUS, Institute for Scientific Information bibliographic database, and Cochrane Collaboration's Central Register of Controlled Clinical Trials for controlled clinical trials that weighted the seroprotection rate in patients with ESRD who received oral levamisole + HBV vaccine versus those who received the HBV vaccine alone (control). The fixed-effects Mantel-Haenszel model was applied with the heterogeneity and sensitivity analyses. The response rate, defined as the proportion of patients with seroprotective concentrations of antibodies to HBsAg (>10 mIU/mL) at completion and 6 to 10 months after completion of the HBV vaccine schedule, was the end point of interest and was also analyzed separately. For the tolerability assessment, studies that reported dose reduction, levamisole discontinuation, and their adverse effects including laboratory abnormalities were included.

RESULTS

The literature search identified 4 studies that fulfilled the inclusion criteria (328 patients). The mean ages of the patients in these studies ranged from 41 to 53 years, and sex distribution ranged from 52.6% to 68.0% male. Twenty-two patients received oral levamisole 100 mg/d for 12 days (from 6 days before to 6 days after each vaccination). A total of 106 patients received oral levamisole 80 to 120 mg for 4 to 6 months. Aggregation of study results suggested a significant increase in response rate in the group that received levamisole + HBV vaccine compared with the control group (pooled odds ratio [OR] = 2.77 [95% CI, 1.56-4.94]) after completion and 6 to 10 months after the vaccination period (pooled OR = 3.96 [95% CI, 1.71-9.18]). The test of heterogeneity was not statistically significant in either group. Five patients underwent dose reduction due to mild adverse events. In one trial, 3 patients died, 1 of whom was receiving levamisole; however, the authors did not provide the causes of death. No other serious adverse events were reported with levamisole administration.

CONCLUSION

The results from this meta-analysis suggest significant benefit in the administration of levamisole as an adjuvant to HBV vaccine to increase seroprotection in patients with ESRD.

Therapy for chronic hepatitis B infection

Interferon-alpha is currently the only therapy approved for treatment of chronic HBV in the United States and Europe. Interferon-alpha therapy causes loss of HBeAg and HBV DNA in approximately a third of treated patients, and the loss of these markers of active viral replication is associated with improvements in hepatic histology and ALT levels. However, the long-term effects of interferon-alpha on morbidity and mortality, and especially on the incidence of the complications of chronic HBV infection, remain to be defined. The currently available treatment for chronic HBV is far from perfect. Interferon therapy is usually associated with significant side effects and requires subcutaneous administration. Additionally, there are a large number of patients who either fail to meet criteria for treatment, or who, with therapy, fail to respond (at least 60% of all patients). Moreover, interferon treatment is expensive (approximately $5,000 for a 16 week course of 5MU daily). Hence the search continues for effective, orally-available and cost-efficacious therapy. Of the agents available, the nucleoside analogues appear to have the greatest promise. The availability of cell culture systems and animal models for studying potential anti-HBV drugs will aid in the future development of these agents. Therapeutic vaccines, and combination therapies (given either concurrently or sequentially) may also play a future role in the management of chronic HBV infection. While prevention of disease must be a primary goal in the war against this common infection, a continued focus must be maintained on the treatment of the approximately 300 million individuals world-wide with established chronic HBV infection.

Treatment of chronic hepatitis B

Chronic infection with the hepatitis B virus (HBV) is a major cause of worldwide morbidity and mortality. A large number of therapeutic approaches has been tried, including interferon (IFN), nucleoside analogues and immunomodulators. To date controlled clinical trials have shown that only IFN is of long-term value but many patients fail to respond to treatment. New approaches to treating patients with IFN-resistant hepatitis B are currently undergoing clinical and experimental evaluation, and it seems likely that new therapeutic agents will be available in the near future.