Hepatitis B virus (HBV) causes a wide spectrum of liver diseases, such as fulminant or acute hepatitis, chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma. The number of individuals infected with this virus has been estimated to be as high as 350 million. Thus, in addition to global hepatitis B vaccination, effective treatment of chronic hepatitis B is also needed.
Currently, there are no effective antiviral treatments to cure HBV infection in patients with chronic hepatitis B. Five drugs have been approved for the treatment of chronic hepatitis B at present: conventional interferon (IFN) alpha, lamivudine, adefovir dipivoxil, pegylated IFN alpha and recently entecavir. Conventional IFN alpha monotherapy has a narrow range of efficacy. Lamivudine, is relatively cheaper, better tolerated, and has been shown to be effective in patients with both hepatitis B e antigen (HBeAg)-positive and -negative chronic hepatitis B. However, virologic response to lamivudine is not as durable as that occurred spontaneously or induced by IFN treatment. In addition, prolonged lamivudine treatment is commonly associated with the emergence of drug-resistance HBV mutants accompanied by the development of breakthrough hepatitis. Adefovir is potent and has been approved for the treatment of chronic hepatitis B in several countries, but is nephrotoxic at daily doses higher than 10 mg and is still not available widely. Entecavir, a carbocyclic deoxyguanosine analog, which is active against both lamivudine- and adefovir dipivoxil-resistant HBV, is the most potent anti-HBV agent ever discovered,11 however, its long-term efficacy remains to be evaluated. Pegylated IFN alpha has recently been shown to be superior to conventional IFN alpha and lamivudine, and has also been approved for the treatment of chronic hepatitis B. Overall, satisfactory virologic and serologic responses could be achieved using pegylated IFN alpha alone in around 30-44% of these patients. Nevertheless, better treatment options are still needed for the remaining \>50% non-responders.
Although the best treatment choice for chronic hepatitis B is not clarified yet, certain therapeutic concepts could be derived from the experience of treating patients with chronic hepatitis C. A major advancement in treating hepatitis C virus (HCV) infection has been the development of combination therapy with IFN and ribavirin. IFN monotherapy is limited by poor sustained virologic responses, even when higher doses of IFN are used. IFN plus ribavirin combination therapy, in contrast, results in much improved treatment outcomes. In our previous study and others, sustained remission rate after cessation of therapy were significantly higher in patients receiving combination therapy than those receiving IFN alone. Therefore, combination therapy with IFN and ribavirin has been recommended as the standard treatment regimen for chronic hepatitis C. Furthermore, we have used ribavirin and IFN combination for the treatment of dual chronic hepatitis B and C, and the results also revealed that the efficacy of clearing HCV RNA was not affected by the presence of HBV infection. Interestingly, after a little more than 2-year post-treatment follow-up, we found that a significant portion (21%) of the responsive patients also cleared HBsAg. These findings imply that this combination regimen might be also effective for the control of chronic hepatitis B. We thus conducted a randomized, multi-center, placebo-controlled study in patients with HBeAg-positive chronic hepatitis B.
