Clonal evolution of multidrug resistant hepatitis B virus during entecavir rescue therapy

De novo entecavir+adefovir dipivoxil+lamivudine triple-resistance mutations resulting from sequential therapy with adefovir dipivoxil, and lamivudine

Background

Entecavir-resistance mutations are commonly induced by entecavir treatment in chronic hepatitis B patients. However, entecavir+adefovir dipivoxil+lamivudine triple-resistance mutations induced by sequential or combination treatment with lamivudine and adefovir dipivoxil have never been reported.

Results

We retrospectively reviewed 1200 patients who had been tested for anti-HBV drug resistance at Beijing Ditan Hospital of Capital Medical University, and five patients showing multidrug resistance to lamivudine and adefovir dipivoxil were enrolled. Stored serum samples were used for genetic analysis, which yielded a total of 135 clones. Entecavir+adefovir dipivoxil+lamivudine triple-resistance mutations were identified in 60 % (3/5) entecavir-naïve patients who received sequential therapy with adefovir dipivoxil and lamivudine. Specifically, we found one rtM204I+rtL180 M+rtM250 V+rtA181 V clone among 23 clones from patient 1 (4.35 %), one rtM204 V+vrtL180 M +rtM250 V+rtA181 V clone among 24 clones from patient 2 (4.17 %), and 2 clones harboring rtM204 V+rtL180 M+rtM250 V+rtA181 V and rtM204 V+rtL180 M+rtI169 V+rtA181 V among 20 clones from patient 3 (10.0 %). The other 2 patients showed multidrug resistance after lamivudine/telbivudine and adefovir dipivoxil combination therapy, but no entecavir-resistance mutations were found in these two patients.

Conclusion

De novo entecavir+adefovir dipivoxil+lamivudine triple-resistance mutations can be induced by sequential therapy with adefovir dipivoxil and lamivudine in patients who never take entecavir. These results provide important information for sequential therapy with adefovir dipivoxil and lamivudine and the use of entecavir as a rescue therapy for these patients with multidrug resistance.

Electronic supplementary material

The online version of this article (doi:10.1186/s12941-016-0138-0) contains supplementary material, which is available to authorized users.

Current status of immunomodulatory therapy in chronic hepatitis B, fifty years after discovery of the virus: Search for the "magic bullet" to kill cccDNA

Chronic hepatitis B (CHB) is currently treated with IFN-α and nucleos(t)ide analogues, which have many clinical benefits, but there is no ultimate cure. The major problem consists in the persistence of cccDNA in infected hepatocytes. Because no antiviral drug has been evaluated which significantly reduces copies of cccDNA, cytolytic and noncytolytic approaches are needed. Effective virus-specific T- and B-cell responses remain crucial in eliminating cccDNA-carrying hepatocytes and for the long-term control of HBV infection. Reduction of viremia by antiviral drugs provides a window for reconstitution of an HBV-specific immune response. Preclinical studies in mice and woodchucks have shown that immunostimulatory strategies, such as prime-boost vaccination and PD-1 blockade, can boost a weak virus-specific T cell response and lead to effective control of HBV infection. Based on data obtained in our preclinical studies, the combination of antiviral drugs and immunomodulators may control HBV viremia during a patient's drug-off period. In this article, we review current immune-modulatory approaches for the treatment of chronic hepatitis B and the elimination of cccDNA in preclinical models. This article forms part of a symposium in Antiviral Research on "An unfinished story: from the discovery of the Australia antigen to the development of new curative therapies for hepatitis".