• Study 307 (Lot Consistency) achieved its primary endpoint, showing that three vaccine lots induced a comparable immune response thereby demonstrating the consistency of the manufacturing process
• A durable immunogenicity response was observed following primary vaccination as well as boosting which matched the levels previously associated with protection

GAITHERSBURG, Md., Oct. 12, 2022 /PRNewswire/ -- Novavax, Inc. (Nasdaq: NVAX), a biotechnology company dedicated to developing and commercializing next-generation vaccines for serious infectious diseases, today presented data from the Phase 3 PREVENT-19 trial and Study 307 (Lot Consistency) at the World Vaccine Congress Europe 2022. PREVENT-19 data in both adults aged 18 and older and adolescents aged 12 through 17 showed the prototype Novavax COVID-19 vaccine (NVX-CoV2373) achieved its pre-specified immunologic endpoint. Study 307 (Lot Consistency) met its primary endpoint, showing that three lots of the Novavax COVID-19 vaccine tested as a heterologous booster induced consistent immune responses in previously vaccinated adults aged 18 to 49.

"These data further demonstrate the consistent immunogenicity and safety profile of the Novavax COVID-19 vaccine as a booster, regardless of previous vaccine history," said Gregory M. Glenn, M.D., President of Research and Development, Novavax. "These data are an early indication that our vaccine may be effective against variants such as Omicron. We have ongoing trials further exploring the Novavax COVID-19 vaccine's potential as an effective booster against these variants, including BA.4/5, and look forward to sharing these data."

PREVENT-19 adult and adolescent homologous boosting

In the PREVENT-19 trial, a single homologous booster dose was given to select adult participants aged 18 and older, approximately eight or 11 months after their primary series. Following a booster dose, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) anti-spike (anti-S) Immunoglobulin G (IgG; a type of antibody) levels increased significantly relative to pre-boost levels, rising above the level correlated with 95% vaccine efficacy in a recent USG study. Neutralizing antibodies against the prototype strain also increased by 34- to 27-fold compared to pre-boost levels when boosted at eight or 11 months. Boosting also increased IgG and human angiotensin converting enzyme 2 (hACE2) receptor inhibition antibody levels against Omicron BA.1, BA.2, and BA.5 variants, with levels that are comparable to those observed in Phase 3 efficacy studies.

In the pediatric expansion of PREVENT-19 which evaluated boosting in adolescents aged 12 through 17, a single homologous booster dose was evaluated for anti-S IgG, hACE2 receptor inhibition and neutralization antibody responses. Following boosting, neutralizing titers were 2.7-fold higher than those seen with primary vaccination, and a significant boost was observed for antibody against Omicron BA.1, BA.2, and BA.5.

In both adults and adolescents, a third dose of the Novavax COVID-19 vaccine decreased the antigenic distance between SARS-CoV-2 variant and prototype virus strains, suggesting benefit for the prevention of COVID-19 against contemporary variants such as Omicron. Additionally, in both adults and adolescents, booster doses were well tolerated, with mostly mild to moderate reactogenicity that was of short duration.

Study 307 (Lot Consistency) adult homologous and heterologous boosting

Study 307 (Lot Consistency) achieved its primary endpoint, showing that three lots of the Novavax COVID-19 vaccine induced consistent immune responses in adults aged 18 to 49. Further, anti-S IgG titers were within the range previously found to correlate with high efficacy in the PREVENT-19 Phase 3 trial. Safety was also consistent across lots, with no serious related treatment-emergent adverse events (AE). These findings confirm a consistent vaccine manufacturing process.

Further, heterologous boosting responses were consistent across participants who received primary vaccines from Moderna, Pfizer, or Johnson & Johnson, with IgG levels approximating levels observed in PREVENT-19.