On Mar. 24, 2020, Novavax announced positive top-line results of its pivotal Phase 3 clinical trial of NanoFlu, its recombinant quadrivalent seasonal influenza vaccine candidate with its proprietary Matrix-M adjuvant, in adults aged 65 and older.

Using the U.S. Food and Drug Administration (FDA) criteria for accelerated approval of seasonal influenza vaccines, the trial evaluated the immunogenicity and safety of NanoFlu compared to Fluzone Quadrivalent, a U.S.-licensed quadrivalent influenza vaccine.

The trial’s primary objectives were to demonstrate non-inferior immunogenicity of NanoFlu compared to Fluzone Quadrivalent using the day 28 ratio of geometric mean titers (GMT) and the difference in seroconversion rates (SCR), as well as the overall safety of NanoFlu. Immunogenicity was measured by hemagglutination inhibition (HAI) assays using egg-derived reagents.

• NanoFlu achieved the primary endpoints, both GMT and SCR, for all four strains included in the vaccine.
• NanoFlu was well-tolerated and had a safety profile comparable to Fluzone Quadrivalent with a modest increase in local adverse events (AEs).

The trial’s key secondary endpoints assessed GMT and SCR, but with an HAI assay based on wild-type reagents, which are expected to provide a more accurate assessment of clinically relevant HAI antibody responses against circulating wild-type viruses.