At The Liver Meeting, Barinthus Biotherapeutics (formerly Vaccitech), announced data from a study examining their immunization candidate, VTP-300, used together with Arbutus Biopharma’s investigational HBV therapeutic, imdusiran. Investigators found the combination of imdusiran and VTP-300 demonstrated meaningful reductions of hepatitis B surface antigen (HBsAg) levels that were maintained well below baseline.
“Imdusiran consistently delivers compelling efficacy and safety data in multiple Phase 2a populations and combinations. In this trial, all but 1 patient reached surface antigen levels below 100 IU/mL and one reached <LLOQ (lower limit of quantification) with 24 weeks of imdusiran plus NUC therapy alone, which is a meaningful achievement as we believe lowering surface antigen is key to promoting host HBV-specific immune reawakening,” Arbutus Biopharma Chief Medical Officer Karen Sims, MD, PhD, said in a statement.
VTP-300 consists of an initial dose using the ChAdOx vector and a secondary dose(s) using the MVA-vectored platform, both encoding multiple hepatitis B antigens, including full-length surface, modified polymerase, and core antigens. VTP-300 is the first antigen-specific immunotherapy that has been shown to induce sustained reductions in HBsAg.
Imdusiran, which is an RNA interference (RNAi) therapeutic specifically designed to reduce all HBV viral proteins and antigens including hepatitis B surface antigen. This is thought to be a key prerequisite to enable reawakening of a patient’s immune system to respond to the virus. Imdusiran targets hepatocytes using Arbutus’ novel covalently conjugated N-Acetylgalactosamine (GalNAc) delivery technology enabling subcutaneous delivery. Clinical data generated thus far has shown single and multiple doses of imdusiran to be generally safe and well-tolerated, while also providing meaningful reductions in hepatitis B surface antigen and hepatitis B DNA. Imdusiran is currently in multiple Phase 2a clinical trials.
