Vir Biotechnology, Inc. announced new data from its ongoing Phase 2 clinical trials of VIR-2218 and ongoing Phase 1 studies of VIR-3434 in patients with chronic hepatitis B virus (HBV) infection. The results, which demonstrate positive safety findings plus a reduction in hepatitis B surface antigen (HBsAg) for both compounds, were presented in two oral and two poster presentations at the European Association for the Study of the Liver (EASL) International Liver Congress 2021, which is taking place virtually. In summary, data presented this week demonstrate the promising safety profile and potential durable response of VIR-2218, an investigational small interfering ribonucleic acid (siRNA) that mediates RNA interference (RNAi), through 48 weeks. In a separate analysis evaluating VIR-2218 in combination with pegylated interferon alfa (PEG-IFN-a) for 12 weeks, a more rapid and substantial HBsAg decline was observed in the co-administration cohort compared to VIR-2218 alone. The treatment regimen resulted in no new safety signals. Additionally, two new analyses from an ongoing Phase 1 trial of VIR-3434 showed no safety signals in healthy volunteers dosed with up to 3,000 mg, and a rapid reduction in HBsAg levels one week after subcutaneous administration of this investigational HBV-neutralizing monoclonal antibody, which has been Fc engineered to include the XX2 “vaccinal mutation,” allowing it to potentially function as a T cell vaccine.