Investigators of the phase 2 study also found a comparable reactogenicity to the individual influenza and COVID-19 vaccines from Novavax or authorized vaccine comparators.
Novavax’s COVID-Influenza Combination, a standalone influenza and high-dose COVID-19 vaccine candidate, showed a reassuring preliminary safety profile with all 3 vaccines in the combination demonstrating preliminary robust immune responses, according to a press release from the company. The combination vaccine candidate is comprised of Novavax’s recombinant protein-based COVID-19 vaccine, quadrivalent influenza vaccine candidate, and saponin-based Matrix-M adjuvant.
Additionally, there was a comparable reactogenicity to the individual influenza and COVID-19 vaccines from Novavax or authorized vaccine comparators.
"The reactogenicity results support our previous observations that this technology is well suited for combination vaccines because large amounts of antigen can be incorporated without impacting tolerability," Filip Dubovsky, MD, president of Research and Development at Novavax, said in the release. "The immune responses we observed were robust, and the data we have shared today significantly increase the probability of phase 3 success."
In the phase 2 trial, investigators evaluated the safety and immunogenicity of different formulations of the vaccine candidates and higher doses of the company’s COVID-19 vaccine in adults aged 50 to 80 years. The phase 2 dose-confirmation trial will be conducted in 2 parts.
Study investigators evaluated safety as the primary endpoint for the formulations of the combination vaccine candidate and the quadrivalent influenza vaccine candidate compared to Fluad, Fluzone High-Dose Quadrivalent (Fluzone HD), and a high-dose COVID-19 vaccine candidate in the patient population. All 3 vaccine candidates contain the Matrix-M adjuvant, which is patented by Novavax.
The preliminary findings showed that the safety profiles and reactogenicity were comparable to Fluad and Fluzone HD. The reactogenicity was consistent as the adjuvant or antigen dose was increased.
Further, there were no adverse events (AEs) of interest, no potential immune-mediated conditions, and no treatment-related serious AEs. Investigators reported that unsolicited AEs occurred in 25% fewer of any group and were consistent with the diagnoses in older adults.
Both local and systemic symptoms were mostly mild and moderate, occurring at rates that were comparable to Fluad and Fluzone HD. Additionally, the combination vaccine candidate achieved both immunoglobulin G (IgG) and neutralizing levels when compared to the company’s prototype COVID-19 vaccine, NVX-CoV2373.
Other formulations of the combination also achieved responses to both SARS-CoV-2 and the 4 homologous influenza strains, which were comparable to reference comparators. The preliminary results support the prioritization for advanced development, according to Novavax.
Furthermore, the investigators reported that the stand-alone influenza vaccine candidate achieved statistically significant hemagglutination inhabitation antibody responses 31% to 56% higher for all 4 strains when compared to Fluad. They also found that the titers were 44% (H1N1) to 89% (H3N2) higher for A strains and statistically non-inferior for B-strains when compared to Fluzone HD.
The highest dose of the standalone COVID-19 vaccine candidate achieved statistically significant anti-S IgG and neutralization responses, which were approximately 30% higher than the company’s prototype COVID-19 vaccine. The vaccine also maintained comparable safety and reactogenicity to the currently authorized dose level of Nuvaxovid.
Positive phase 2 topline results show Novavax’s COVID-Influenza Combination, stand-alone influenza and high-dose COVID vaccine candidates demonstrate robust immune responses. News release. Novavax. May 9, 2023. Accessed May 11, 2023. https://ir.novavax.com/2023-05-09-Positive-Phase-2-Topline-Results-Show-Novavaxs-COVID-Influenza-Combination,-Stand-alone-Influenza-and-High-dose-COVID-Vaccine-Candidates-Demonstrate-Robust-Immune-Responses