Nanoparticle Flu Vaccine for Older Adults Begins Phase 2 Trial

A new phase 2 trial is underway for an investigative nanoparticle seasonal influenza vaccine in older adults. Novavax, creators of the NanoFlu, will undergo a randomized, observer-blind trial prior to a meeting with the US Food and Drug Administration (FDA) to discuss appropriate phase 3 trial design accommodated by accelerated approval designation.

In the new clinical trial, investigators will assess the efficacy, safety, and tolerability of NanoFlu doses and formulations—both adjuvanted and unadjuvanted—in comparison to a pair of US marketed vaccines. Approximately 1375 healthy older adults across the country will be enrolled, with Novavax’s intent to select a dose and formulation of the vaccine that can be brought forward into its phase 3 immunogenicity trial.

NanoFlu trivalent formulation first reported topline phase 1 and 2 clinical trial results in older adults in Feburary of this year. When compared to Fluzone HD, the investigative vaccine demonstrated acceptable safety and a short-term reactogenicity. Investigators also reported patient hemagglutination inhibition (HAI) immune responses were 28% to 64% greater in those treated with NanoFlu versus those treated with homologous and 4 generations of drifted wild-type A(H3N2) influenza strain. The vaccine also reported higher HAI responses than the homologous A(H1N1) strain, and comparable responses against the homologous B/Brisbane strain.

Influenza is a particular concern among adults aged 65 years or older, advised the US Centers for Disease Control and Prevention (CDC), due to the population’s increased risk of infection and comorbidities. Vaccination has also been pointed to the greatest resolve—a 2017 study run by the CDC showed that rates of death, intensive care unit admissions and length of stay, and overall hospitalization duration were most significantly improved by vaccine in people aged 65 years and older.

As a recombinant hemagglutinin (HA) protein nanoparticle vaccine, the NanoFlu contains Novavax’s Matrix-M adjuvant. The adjuvant stimulates entry of antigen-presenting cells into the injection site and enhances antigen presentation in local lymph nodes, result in potent and well-tolerated effects in older adult populations.

Gregory Glenn, MD, president of Research and Development at Novavax, suggested the characteristics and makeup of the investigative vaccine make it a sorely missing option in the influenza market.

“The dual problems of antigenic drift and antigenic changes resulting from egg-based vaccine production have, in recent years, resulted in generally poor influenza vaccine effectiveness with potentially severe medical consequences, particularly in older adults,” Glenn said in a statement. “A substantially improved seasonal influenza vaccine is a widely recognized, high-priority unmet medical need.”

Stanley C. Erck, president and chief executive officer of Novavax, is anticipating topline results from the phase 2 trial in the Q1 of 2019. He called the initiation of this phase “an important milestone” for the company.

“We continue to believe NanoFlu is a differentiated flu vaccine capable of better addressing a global public health problem, and can thereby capture a significant share of the multi-billion-dollar seasonal influenza vaccine market,” Erck said.