Action Mechanisms and Scientific Rationale of Using Nasal Vaccine (HeberNasvac) for the Treatment of Chronic Hepatitis B

Nasvac (HeberNasvac(®)) is a novel therapeutic vaccine for chronic hepatitis B (CHB). This product is a formulation of the core (HBcAg) and surface (HBsAg) antigens of the hepatitis B virus (HBV), administered by nasal and subcutaneous routes, in a distinctive schedule of immunizations. In the present review article, we discuss the action mechanisms of HeberNasvac, considering the immunological properties of the product and their antigens. Specifically, we discuss the capacity of HBcAg to activate different pathways of innate immunity and the signal transduction after a multi-TLR agonist effect, and we review the results of recent clinical trials and in vitro studies. Aimed at understanding the clinical results of Nasvac and other therapeutic vaccines under development, we discuss the rationale of administering a therapeutic vaccine through the nasal route and also the current alternatives to combine therapeutic vaccines and antivirals (NUCs). We also disclose potential applications of this product in novel fields of immunotherapy.