Barinthus presents EOT data from Phase 2a trial of imdusiran, VTP-300

Data from IM-PROVE II as of the data cutoff on April 12, 2024, indicate that treatment with imdusiran, Arbutus’ RNAi therapeutic candidate, followed by Barinthus Bio’s T-cell stimulating immunotherapeutic candidate, VTP-300, was generally well-tolerated and observed to maintain low HBsAg levels during the post-treatment follow-up period. The data were presented today by Dr. Kosh Agarwal, MD, Consultant Hepatologist and Transplant Physician at the Institute of Liver Studies at King’s College Hospital, London, during a session focused on new treatments for viral hepatitis B at the EASL Congress. Dr. Agarwal presented the following data from 38 of 40 participants that were on stable NUC therapy throughout the treatment period. They received imdusiran for 24 weeks and were then randomized to receive either VTP-300 or placebo at Weeks 26 and 30: Robust reductions of HBsAg were observed during the imdusiran lead-in period with 95% of patients achieving HBsAg less than100 IU/mL before undergoing dosing in the VTP-300 treatment or placebo groups. At 24-weeks post-EOT, there was a significant difference in HBsAg levels between the VTP-300 treatment group and placebo. 94% of participants in the VTP-300 treatment group achieved HBsAg levels of less than100 IU/mL and 36% had less than10 IU/mL at EOT compared to the placebo group, 84% and 21%, respectively. Similarly, at 24-weeks post-EOT, the VTP-300 treatment group had lower HBsAg levels with 80% of participants at less than100 IU/mL and 60% at less than10 IU/mL than the placebo group, 16% and 0%, respectively. 84% of participants in the VTP-300 treatment group met criteria at EOT to discontinue NUC therapy vs 52% in the placebo group. In the VTP-300 treatment group, 20% of participants achieved undetectable HBsAg at 24-weeks post-EOT and a further 20% of participants had a greater than1.5log10 decline between the last two visits during the NUC therapy discontinuation follow-up period. Treatment with imdusiran and VTP-300 was generally well-tolerated. There were no reported SAEs, Grade 3 or 4 AEs or discontinuations due to treatment. The most common treatment-related AEs in two or more patients were injection site-related and transient ALT increases.