Antiviral effects of anti-HBs immunoglobulin and vaccine on HBs antigen seroclearance for chronic hepatitis B infection.

Background and Aims: Interferon and nucleotide/nucleoside analogues are the main treatments for chronic hepatitis B. These drugs effectively reduce serum hepatitis B virus (HBV) DNA titers but fail to sufficiently reduce hepatitis B surface antigen (HBsAg) levels. Following the recent identification of sodium taurocholate cotransporting polypeptide as a receptor for HBV entry, inhibition of HBV entry has become an attractive therapeutic target for chronic hepatitis B treatment. We therefore evaluated the antiviral effects of antibody to HBsAg (anti-HBs) immunoglobulin (HBIG), which can inhibit HBV entry, by in an vivo study and a clinical trial.
Methods: In the in vivo study, HBV-infected mice were generated from human hepatocyte chimeric mice and treated with HBIG. A clinical trial evaluating HBIG therapy in patients was also performed.
Results: In the mouse study, HBV DNA titers were reduced and serum HBsAg titers decreased to undetectable levels following high-dose HBIG injection. On the basis of this result, eight chronic hepatitis B patients, who had received long-term nucleotide analogue treatment, were treated with monthly HBIG injections as an additional treatment. After 1 year of treatment, an HBsAg level reduction of more than 1 log IU/mL was observed in four patients, and three patients became anti-HBs positive. No adverse events occurred during HBIG therapy.
Conclusion: These results suggest that monthly HBIG injection might benefit patients with chronic hepatitis B whose HBsAg titer becomes lower following long-term nucleotide/nucleoside analogue treatment.