Efficacy and safety of an intravenous monoclonal anti-HBs in chronic hepatitis B patients

Background/Aims: In this study the safety and efficacy of a monoclonal anti -HBs, Tuvirumab (Mab), were investigated. Tuvirumab is a human monoclonal a ntibody recognizing the stable 'a'-determinant of the HBsAg. Methods. We in cluded ten chronic hepatitis B patients: four received monotherapy, and six combination therapy with interferon alpha 2b. Results: Because the develop ment of insoluble [HBsAg-HBsAb] complexes led to adverse events, the Mab do se had to be reduced in seven patients. In nine patients treatment was stop ped prematurely because of lack of efficacy, i.e. neutralization of HBsAg i n serum. However, temporary HBsAg levels were reduced by at least 50% in al l patients; in three patients receiving combination therapy, background lev els of HBsAg in serum were reached. A loss of serum HBV-DNA was seen in thr ee patients in the combination group, followed by HBeAg seroconversion in t wo patients. Conclusions: We conclude that Mab was not effective in achievi ng primary efficacy as assessed by neutralization of circulating HBsAg. Whe ther a combination of Mab with an antiviral agent that reduces the HBsAg lo ad - and therefore minimizes the risk of adverse events - may result in cli nical efficacy should be investigated.