Chronic hepatitis B therapy: available drugs and treatment guidelines.

There are currently several drugs approved for the treatment of chronic hepatitis B including recombinant interferons, such as interferon-α and its pegylated formulation, and the nucleos(t)ide analogues, such as lamivudine, adefovir, telbivudine, entecavir and tenofovir. Pegylated-interferon is an immune-modulatory agent that works mainly by enhancing the innate immune response while nucleos(t)ide analogues are oral drugs with direct inhibition of viral replication. Each agent has its own advantages and drawbacks. Pegylated-Interferon treatment has a finite duration without induction of drug resistance but only a limited number of patients achieve a sustained virological response to therapy. On the other hand, the care with nucleos(t)ide analogues requires a long-term treatment with a potential risk of induction of drug resistance, but higher rates of viral replication suppression are achieved. Nevertheless, second generation nucleos(t)ide analogues, such as Entecavir and Tenofovir, have both high genetic barrier to resistance and potent antiviral action. This review describes the mechanisms of antiviral activity and the efficacy of viral suppression of the different available drugs for chronic hepatitis B treatment, considering the recent clinical guidelines for an optimal management of chronic HBV infection.