A couple of excerpts related to VIR-2218.
Chronic Hepatitis B Virus (HBV) Updates
In January, Vir entered into a clinical collaboration with Gilead Sciences, Inc. to evaluate the Company’s HBV-targeting small interfering ribonucleic acid (siRNA), VIR-2218, in a Phase 2 combination therapy trial with selgantolimod (GS-9688), Gilead’s investigational TLR-8 agonist, and nivolumab, an approved PD-1 inhibitor, in both treatment-experienced and treatment-naïve patients with HBV. The trial, which is aimed at developing a functional cure for chronic HBV, is expected to start in 2021.
In late January, the Company announced initial topline data from an ongoing Phase 1 trial evaluating VIR-3434, an HBV-neutralizing monoclonal antibody with the potential to be a therapeutic T cell vaccine, for the treatment of patients with chronic HBV. The first blinded cohort consisted of eight patients with chronic HBV who were taking nucleoside reverse transcriptase inhibitors, two of whom received placebo, and six of whom received a single dose of 6 mg VIR-3434. Six of eight patients responded and achieved a mean 1.3 log10 IU/mL reduction in serum HBV surface antigen (HBsAg) by day eight, the day when nadir was achieved in most patients. Additional clinical data are anticipated in the second quarter of 2021. The Company also expects to initiate a Phase 2 trial of VIR-3434 in combination with VIR-2218 in the second half of 2021.
In February, the Company presented encore data on VIR-2218 at the Asian Pacific Association for the Study of the Liver. Presentations included preliminary results from the Company’s ongoing Phase 2 trial of VIR-2218 (oral) and data characterizing the urine and plasma pharmacokinetics of VIR-2218 (poster). One-year response durability data for VIR-2218 as a monotherapy for HBV are anticipated in the first half of 2021.
During the quarter, the Company continued to progress a Phase 2 combination trial of VIR-2218 with pegylated interferon-alpha (PEG-IFN-α) to evaluate the potential for this combination to result in a functional cure for HBV. Initial clinical data are anticipated in the second quarter of 2021.
The Company expects Brii Biosciences Offshore Limited (Brii Bio) to initiate a Phase 2 trial evaluating VIR-2218 in combination with BRII-179, an investigational T cell vaccine, in the first half of 2021.
VIR-2218 is an investigational subcutaneously administered HBV-targeting siRNA that has the potential to stimulate an effective immune response and have direct antiviral activity against HBV. It is the first siRNA in the clinic to include Enhanced Stabilization Chemistry Plus (ESC+) technology to enhance stability and minimize off-target activity, which potentially can result in an increased therapeutic index. VIR-2218 is the first asset in the Company’s collaboration with Alnylam Pharmaceuticals, Inc. to enter clinical trials.