DURHAM, N.C. & BEIJING & SAN FRANCISCO & CAMBRIDGE-- April 23, 2021 -- Brii Biosciences (Brii Bio), Vir Biotechnology, Inc. (Nasdaq: VIR), and VBI Vaccines Inc. (Nasdaq: VBIV) today announced that the first patient has been dosed in a Phase 2 clinical trial evaluating BRII-835 (VIR-2218), an investigational small interfering ribonucleic acid (siRNA) targeting hepatitis B virus (HBV), in combination with BRII-179 (VBI-2601), an investigational HBV immunotherapeutic, for the treatment of chronic HBV infection. This is the first clinical trial in the field to evaluate the combination of these two HBV mechanisms of action.

The multi-center, randomized, open-label study is designed to evaluate the safety and efficacy of BRII-835 (VIR-2218) compared to the combination of BRII-835 (VIR-2218) and BRII-179 (VBI-2601) with and without interferon-alpha as a co-adjuvant. Both agents have demonstrated proof of mechanism in HBV patients (NCT04507269 BRII-835 China study and ACTRN12619001210167 BRII-179 APEC study). Brii Bio has led the design and implementation of this functional cure proof-of-concept study with the support of VIR and VBI, and is the sponsor of the Phase 2 study (NCT04749368). It will be conducted at sites in Australia, China, Taiwan, Hong Kong Special Administrative Region of China, South Korea, New Zealand, Singapore, and Thailand.

Li Yan, M.D., Ph.D., chief medical officer of Brii Bio, said: “Sustained seroclearance of HBV surface antigen, also known as a functional cure, occurs rarely in the natural history of HBV infection or during the current standard of care treatment. We believe that both viral antigen knockdown with BRII-835 (VIR-2218) and sustained induction of HBV-specific host immune responses by BRII-179 (VBI-2601) are required to remove viral immunosuppression and subsequently break immune tolerance. The combination of these two agents is a step toward developing a functional cure for HBV.”

Phil Pang, M.D., Ph.D., chief medical officer of Vir, said: “This new combination trial represents an important addition to our HBV portfolio approach of combining VIR-2218 with various immunomodulators, including pegylated interferon alpha, VIR-3434 and with a TLR8 agonist, via our previously announced collaboration with Gilead. We look forward to determining if such combinations can stimulate an effective immune response that may result in a finite duration of treatment.”

Francisco Diaz-Mitoma, M.D., Ph.D., VBI’s chief medical officer, said: “We believe that a functional cure for HBV is possible, and will require restoration of HBV-specific immunologic control in addition to viral suppression mechanisms. Data from our previous study suggest BRII-179 (VBI-2601) was able to restimulate both antibody and T cell responses specific to HBV. This combination study represents the first combination of a therapeutic HBV vaccine to restore HBV-immunity with antivirals designed to reduce the levels of HBV surface antigens. We look forward to seeing the outcome of the trial, a milestone that will be meaningful in our collective efforts to provide an effective solution for patients with such a complex and highly infectious virus.”