Dynavax’ flu vaccine is based on the company’s proprietary TLR-9 agonist-based immunostimulatory sequence (ISS) technology and is specifically designed to overcome the limitations of both development-stage pandemic vaccines and standard seasonal flu vaccines. The vaccine is produced by conjugating ISS with two highly conserved viral proteins, nucleoprotein (NP) and the extracellular domain of matrix protein 2 (M2e).
In preclinical tests in mice, the ISS-based flu vaccine has demonstrated the potential to confer cross-protective cellular and antibody- induced immunity against widely divergent flu strains. Results in mice and primates show that co-administration of Dynavax’ flu vaccine with standard vaccine enhances the immune response to the standard vaccine, and may allow reduction of dosage while inducing comparable protective immunity.
In addition, the enhanced immunogenicity and cross-protection of the Dynavax vaccine may provide immunity that can last for more than one year, potentially enabling the elimination of annual vaccination and stockpiling of vaccine for pandemic use.
Dynavax previously presented data showing that immunization with NP-ISS induces potent NP-specific Th1 and cytotoxic T-lymphocyte responses, as well as enhanced responses to hemagglutinin, or HA, when co-delivered with conventional or split vaccine.
New data were presented by Dynavax on its NP-ISS and, for the first time, on its M2e conjugate. Key new findings include that mice immunized with the NP-ISS conjugate and then challenged with drift and shift virus strains demonstrated statistically significant lower viral titers and higher survival rates compared to mice immunized with NP alone or a PBS placebo.
In addition, mice immunized with an M2e-ISS conjugate generated an M2e-specific antibody response that was enhanced with NP formulations.
Both NP-ISS and M2e-ISS have been shown to enhance responses to co- administered standard vaccine in mice, and primates immunized with NP-ISS co-administered with standard vaccine (Sanofi-Aventis’ Fluzone) demonstrated enhanced NP and Fluzone-specific antibody responses.