Tobevibart (VIR-3434) is a human IgG1 lambda monoclonal antibody against hepatitis B virus (HBV) surface antigen (HBsAg). Tobevibart shows potent neutralization against HBsAg from all HBV genotypes in vitro and inhibits viral entry of HBV and hepatitis delta virus (HDV). Recommend Isotype Controls: Human IgG1 lambda2, Isotype Control .