Impact of the Route and Schedule of Immunization on the Serological and Virological Response of Chronic Hepatitis B Patients Treated with HeberNasvac.

HeberNasvac is a recently developed therapeutic vaccine for chronic hepatitis B (CHB) administered by intranasal (IN) and subcutaneous (SC) routes in a 14 days/10 doses schedule. To compare different schedules and routes of immunizations, a group of patients received four different vaccination regimens in a placebo-controlled factorial study. Subsequently, patients were followed for a minimum time of 48 weeks. Samples collected at the end of the follow-up were compared with initial samples. Groups I and II received the product by IN/SC routes, every 14 and 7 days, respectively. Groups III and IV were treated by SC route alone following a 14 and 7 days schedule. A group of 21 CHB patients received the vaccine in four different schedules and eight patients received placebo for a total of 29 patients enrolled. The 61.9% of vaccinees reduced their VL ≥2Log compared with baseline levels and 25% in placebo group. The 47.6% of vaccines reduced HBV levels to undetectable, 25% in placebo. HBeAg loss and seroconversion to anti-HBeAg was only achieved in vaccinees, 4 out of 9 (44.4%), and 40% (8 out of 20) developed anti-HBs response, none in placebo group. Reduction of HBsAg level in ≥1Log was achieved in the 35.0% of vaccinees and in none of the placebo-treated patients. Considering the individual and factorial analysis, significant HBV DNA reduction was detected in groups I and II, immunized by IN/SC routes. A significantly higher proportion of patients reducing VL to ≥2Log was also detected grouping the patients treated by IN/SC routes (G I + II) and grouping those inoculated every 14 days (G I + III), with 72.7% and 63.6%, respectively, compared with the placebo group (25.0%). The patients immunized every 14 days (G I + G III) also reduced the HBsAg levels compared with baseline. In conclusion, after more than 48 weeks of treatment-free follow-up, HeberNasvac-treated patients demonstrated superior responses compared with the placebo group in terms of antiviral and serological responses. The factorial analysis evidenced that the schedule combining the IN route of immunization and the frequency of 14 days resulted in the stronger antiviral and serological responses. Present results support the study of IN-only immunization schedules in future and was consistent with previous results. Long-lasting follow-ups were done to explore histological variables and the progression of serological variables in order to detect late responders. How to cite this article: Freyre FM, Aguiar JA, Cinza Z,