Shares in Vir Biotechnology rose 74% on the strength of data from a blinded, eight-subject cohort in its phase 1 hepatitis B trial. The analysis suggests the neutralizing monoclonal antibody may be more potent than expected and provides a boost to Vir’s prospects of delivering a functional cure.

Investigators enrolled eight patients with chronic hepatitis B virus infection in the 6-mg cohort of Vir’s phase 1 trial. Six of the participants received VIR-3434, an antibody designed to stop the virus from entering hepatocytes. The other two subjects received placebo. The cohort remains blinded, but Vir pooled data from six subjects who had reductions in serum hepatitis B virus surface antigen.

Those six patients experienced a 1.3 log10 IU/mL mean reduction in surface antigen by the eighth day. Levels of the antigen fell to their lowest point in most patients by day eight.