Even though current antiviral treatments based on pegylated interferon, or nucleos (t) ide analogues, in mono or combination therapies, have demonstrated clinical benefit to HBV-infected patients, chronic hepatitis B remains a difficult-to-cure disease. An absolute cure, defined as total elimination of HBV DNA, is currently not achievable, and a functional cure characterised by sustained virological response and HBV surface antigen (HBsAg) clearance off-treatment remains a challenge. Pegylated interferon treatment can lead to a sustained virological response and HBsAg clearance off-treatment in only 3–7% of patients, 1 and it is too often associated with contraindications and adverse effects. Long-term treatment with nucleos (t) ide analogues is better tolerated, but the chance to achieve a sustained virological response and HBsAg loss remains low, 2 and the drugs do not eradicate intrahepatic HBV DNA.

The risk of disease progression and development of hepatocellular carcinoma in chronically HBV-infected patients is clearly associated with high levels of serum HBV DNA and HBsAg. 3 4 Since high levels of serum HBsAg may be responsible for exhaustion of HBsAg-specific T-cell response in chronically infected individuals, an antiviral strategy aimed at suppressing circulating HBsAg could restore virus-specific immune response and promote viral clearance. 5 Zhang et al6 investigated the potential of anti-HBsAg monoclonal antibodies (mAbs) infusion for clearance of circulating HBsAg in chronic infection. The study was based on (i) the previous observation that anti-HBsAg mAbs treatments could have short-term antiviral effects, 7 8 and (ii) the growing interest in mAbs-based immunotherapy for viral diseases, including infections with HIV, HCV and Ebola virus. 9 The therapeutic use of antiviral mAbs was initially based on the mAbs