Barinthus Bio Presents Interim Data from Phase 2b HBV003 Trial and Phase 2a AB-729-202 Trial in Collaboration with Arbutus Biopharma in Chronic HBV Patients at AASLD - Seite 2

Study HBV003: VTP-300 and Low-dose Nivolumab

HBV003 is designed to obtain critical information on treatment dosing regimen with patients receiving VTP-300 and low-dose nivolumab. All Groups receive ChAdOx at Day 1, Groups 1 & 2 receive MVA with nivolumab at Day 29 with Group 2 being dosed again at Day 85, Group 3 receives only MVA at Day 29, followed by nivolumab at Day 36 and a second MVA dose at Day 85 to evaluate PD-1 inhibition timing. Seventy-four out of a planned 120 virally suppressed CHB patients on stable NUC therapy have been enrolled in the trial and 57 have reached Day 113. VTP-300 in combination with nivolumab led to HBsAg declines in all treatment groups, particularly in participants with screening HBsAg levels ≤200 IU/mL.

• >0.5 and >1 log drops have been observed in all groups at Day 113 in 23% and 9% of participants, respectively.
• Participants with an HBsAg level of ≤200 IU/mL at screening were more likely to have >1 log HBsAg reductions (31%) compared to those with HBsAg levels >200 IU/mL at Day 1 (2%).
• Greater mean HBsAg log reductions were observed in Group 2 (ChAdOx-HBV Day 1; MVA-HBV and nivolumab Day 29 and Day 85) but insufficient data for definitive conclusion.
• Seven participants have met the criteria for NUC discontinuation; three have discontinued and two have restarted NUC therapy.
• Preliminary safety data suggest VTP-300 in combination with nivolumab has been generally well tolerated, with no treatment-related SAEs observed or reported. Thyroid dysfunction reported in seven participants attributed to nivolumab administration which has returned to normal in four patients.
  

The HBV003 trial protocol is currently being amended to include only participants with screening HBsAg ≤200 IU/mL. Participants with screening HBsAg ≤200 IU/mL have been observed to benefit the most in the preliminary data, with the trial protocol amendment being focused on improving the overall risk/benefit ratio. People with thyroid autoantibodies, family history of autoimmune thyroiditis, or abnormal thyroid levels will be excluded from trial eligibility to minimize the risk of thyroiditis.

Study AB-729-202: VTP-300 in Combination with Imdusiran (AB-729)

Clinical trial AB-729-202 enrolled forty non-cirrhotic, virally suppressed CHB patients that were on stable NUC therapy. The patients initially received imdusiran (60mg every 8 weeks) for 24 weeks and were then randomized to receive either VTP-300 or placebo at week 26 and 30 (and conditionally at week 38 if they experienced a >0.5 log₁₀ decline in HBsAg between Weeks 26 and 34), in addition to ongoing NUC therapy. The preliminary data include a subset of patients that received the two dose VTP-300 regimen (28/40 patients) and available follow-up data to Week 48 (12/40 patients) and showed the following: