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Influenza: Oral tablet vaccine shows promise in Phase 2 challenge study

Vaxart, Inc., a privately-held, clinical stage biotechnology company developing oral recombinant vaccines administered by tablet rather than by injection, announced today that its H1 influenza oral tablet vaccine demonstrated similar protection against influenza virus as the market-leading injectable quadrivalent influenza vaccine (QIV) in a clinical trial. These results met the efficacy objectives of the Phase 2 influenza A clinical study. The oral tablet vaccine also demonstrated a favorable safety and tolerability profile.

Generic influenza virion
Image/CDC

“Influenza virus continues to be a serious public health problem affecting all age groups and causing severe illness and sometimes death in high-risk populations. While immunization campaigns have grown in efficacy and scale, there remains potential to improve this public health measure,” said Dave Liebowitz, M.D., Ph.D., chief medical officer of Vaxart. “The results of the clinical study suggest that our oral tablet vaccine could address unmet needs given its ease of distribution and administration.”

Data from the Phase 2 influenza A challenge study demonstrated that Vaxart’s influenza oral tablet vaccine provided a 39 percent reduction in clinical disease relative to placebo, compared to a 27 percent reduction by the injectable QIV. The tablet vaccine also showed a favorable safety profile, similar to placebo.

“These results provide clinical proof-of-concept for Vaxart’s groundbreaking oral tablet vaccine technology,” said Wouter Latour, M.D., M.B.A., chief executive officer of Vaxart. “Currently less than half of the approximately 320 million eligible Americans are vaccinated against influenza each year. A convenient and effective tablet vaccine could significantly increase current vaccination rates and generate important public health benefits for at-risk groups and the population as a whole.”

The Phase 2 influenza A challenge trial was a randomized, double-blind study consisting of three groups. Subjects received either a single dose of the Vaxart oral tablet vaccine and a placebo intramuscular injection, a QIV injection and a placebo tablet, or a double placebo. Subjects were challenged intranasally with homologous A strain influenza virus 90-120 days after vaccination. The main objective of the study was to evaluate the percentage of subjects protected by the Vaxart oral tablet vaccine against influenza illness, measured as a reduction in clinical symptoms and laboratory-confirmed homologous influenza A infections, compared to QIV and placebo.

The Phase 2 study was completed with support from the Office of Biomedical Advanced Research and Development Authority (BARDA). Vaxart received a $13.9 million contract from BARDA in September 2015 to support the advanced development of more effective influenza vaccines to ultimately improve seasonal and pandemic influenza preparedness.

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