Vaccitech plc announced present positive final data from the HBV002 clinical trial at the European Association for the Study of the Liver (EASL) Congress 2023 – The International Liver CongressTM taking place June 21-24 in Vienna, Austria. HBV002 (NCT04778904) is a Phase 1b/2a clinical trial of VTP-300 in adults with chronic Hepatitis B (CHB). The data will be presented as a poster at EASL on, June 24 (Poster ID: SAT-198), by Eleanor Barnes, Professor of Hepatology and Experimental Medicine at Oxford University.

Meaningful, durable reductions of Hepatitis B Surface Antigen (HBsAg) were seen in all participants with a >0.5 log10 reduction in HBsAg who received VTP-300 alone (Group 2) or in combination with a single administration of low-dose PD-1 inhibitor, nivolumab (Group 3). Two of five patients with baseline HBsAg below 100 IU/mL in Group 3, developed a non-detectable HBsAg level, which continued eight months after last dose. Reductions in HBsAg were most prominent in those with lower baseline HBsAg.

Importantly, all participants who received VTP-300 and experienced a >0.5 log10 reduction in HBsAg had durable responses with reductions in HBsAg persisting through to the last measurement eight months post-final dose. VTP-300, encoding Hepatitis B virus (HBV) genotype C antigens, led to a decline in HBsAg in the majority of people infected with genotypes B and C viruses. In addition, VTP-300-induced T cells showed cross-reactivity to the core antigen from genotypes A to E in ELISpot assays using PBMC from VTP-300-treated healthy subjects and genotype-specific peptides A-E. A robust T cell response was generated against all VTP-300 antigens and was highest in the VTP-300 alone group.

In that group, there was a relation between ELISpot responses and HBsAg decline.