Vaxart oral recombinant vaccines are formulated as tablets that are enterically coated for efficient delivery to the small bowel. The enteric coating protects the active ingredient from the acidic environment in the stomach.
By targeting the small bowel, the vaccines engage the finely-tuned immune system of the gut to generate broad systemic and mucosal immune responses for robust, persistent immunity.
Vaxart is currently developing a liquid formulation for young children and adults who are unable to ingest tablets.
Vaxart’s delivery platform employs a modular approach using a replication-incompetent adenovirus type 5 (Ad5) vector that delivers two payloads to the cells of the mucosal epithelium of the small bowel. One payload is the gene coding for the selected pathogen-specific protein antigen. The other payload, which is always co-delivered, is the gene coding for the Toll Like Receptor-3 (TLR-3) agonist, an adjuvant that activates the innate immune system, and was selected for its ability to stimulate broad immune responses. Every vaccine contains the TLR-3 adjuvant component.
Vaxart vaccines currently in development feature:
Safety: To date, Vaxart has dosed more than 400 subjects with our tablet vaccines for H5N1 flu, H1N1 flu, influenza B, norovirus and respiratory syncytial virus (RSV). We have observed a consistently favorable safety and tolerability profile in all of the studies to date.
Efficacy and Immunogenicity: In a Phase 2 influenza challenge study, Vaxart’s tablet vaccine demonstrated protection comparable to that of the best-selling injectable influenza vaccine. In subjects receiving the Vaxart tablet vaccine, protection was strongly correlated with mucosal immune responses, a unique feature of the Vaxart tablet vaccines, and a result not seen with the injectable vaccine.
Two Phase 1 norovirus clinical studies demonstrated that Vaxart’s tablet vaccine generated robust systemic and mucosal immune responses. The presence of norovirus-specific fecal antibodies at day 180 post-immunization demonstrated persistence of the immune response.