HBsAg reduction was evident in 30 months follow-up after administration with therapeutic vaccine containing HBs/HBc antigen in chronic HBV carriers

Objective: We have developed CVP-NASVAC, a mixture of HBs/HBc antigen containing therapeutic vaccine (NASVAC) and mucoadhesive excipient carboxyl vinyl polymer (CVP), and reported its HBsAg reduction in HBV carrier at 6- and 18-months follow-up. In this study, we assessed the long term HBsAg reduction by CVP-NASVAC in HBV carriers for 30-months follow-up.
Methods: We conducted an open-labeled clinical trial of CVP-NASVAC for HBV carriers under the approval of institutional review board (IRB#E18-27) and registration to jRCT (#jRCTs061180100). Participants received CVP-NASVAC via nose 10 times every two weeks. We analyzed the data at 30 months after final administration of CVP-NASVAC.
Results: Total 31 participants, n=13 under nucleos(t)ide analogue (NAs), n=18 without NAs (w/o NAs), completed 30-months follow-up. 45.2% participants developed and maintained anti-HBs. 84.6% in NAs and 77.8% in w/o NAs displayed significant HBsAg reduction from baseline and the HBsAg reduction was -0.188 Log₁₀ IU/ml and -0.549 Log₁₀ IU/ml, respectively. Three patients lost HBsAg. HBV-DNA was not detected in all the NAs. Mean HBV-DNA reduction in w/o NAs was 11.0%. HBcrAg decreased in all 11 HBcrAg detected patients. Three patients achieved functional cure at 30 months.
Conclusion: Significant HBsAg reduction was evident in 30 months follow-up after final administration of CVP-NASVAC. The CVP-NASVAC could be a long time effective immune therapy for reducing HBsAg in chronic HBV carriers.