Current pharmacotherapy for hepatitis B infection.

Chronic infection with the hepatitis B virus (HBV) affects 350 million people worldwide, or approximately 5% of the global population, and commonly results in cirrhosis and hepatocellular carcinoma. Until recently, the only available treatment was injectable interferon alpha and response rates were suboptimal. Moreover, this expensive and toxic therapy had little applicability in the endemic regions of the world, i.e., Asia and Africa. The realisation that orally available nucleoside and nucleotide agents may effectively control this infection opened a new era in the management of chronic hepatitis B. Oral lamivudine recently became approved for treatment of hepatitis B worldwide. It is free of significant toxicity, improves liver histology and rapidly diminishes HBV DNA levels; lamivudine is expected to become the first-line therapy of choice. Nevertheless, the consistent emergence of lamivudine-resistant variants mandates the need to develop additional therapeutic agents. Adefovir dipivoxil, a nucleotide, and entecavir, a nucleoside agent, are promising new drugs that might eventually be used in combination with lamivudine and therefore reduce the incidence of drug resistance. There is a critical need to advance the research of hepatitis B antiviral agents so that effective combination therapies can become widely available.