aInstitute of Digestive Disease, The Chinese University of Hong Kong bDepartment of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong.
PURPOSE OF REVIEW:
Chronic hepatitis B virus (HBV) infection is a leading cause of cirrhosis and hepatocellular carcinoma globally. This article reviews recent therapeutic developments and highlights the significance of HBV genotypes.
Seven drugs (two interferons and five oral antiviral drugs) are currently available for the treatment of chronic hepatitis B. Peginterferon has the advantage of finite treatment duration and higher off-treatment durability, but causes more side effects. On-treatment monitoring with hepatitis B surface antigen and HBV DNA levels can predict response and serve as a stopping rule. Oral antiviral therapy carries fewer side effects, but long-term treatment is often required. Regular HBV DNA monitoring is essential for detecting drug resistance and suboptimal responders. HBV is divided into eight genotypes based on a difference in genetic sequence of 8% or more. Genotype C is associated with prolonged immune clearance and a higher risk of progression to cirrhosis and hepatocellular carcinoma. Patients with genotype D HBV infection have low response rate of 7-25% to peginterferon.
The availability of effective antiviral therapy and virological assays has transformed HBV treatment in the past two decades. The differences in response rate and side-effect profile call for individualized treatment selection.