Vaxart Announces Additional Data from Hamster Challenge Study of its Oral COVID-19 Vaccine

Robust Immune Response and Significantly Reduce Viral Load

SOUTH SAN FRANCISCO, Calif., Nov. 12, 2020 (GLOBE NEWSWIRE) -- Vaxart, Inc., (NASDAQ: VXRT), a clinical-stage biotechnology company developing oral vaccines that are administered by tablet rather than by injection, announced today additional results from its Hamster Challenge Study:

• Significant reduction in lung viral load of 4-5 logs in hamsters that received two oral vaccine doses, as compared to non-vaccinated animals.
  
  
• Potent induction of antibody response, with serum IgG antibody titers above 10,000 in hamsters that received two oral vaccine doses.
  
  
• Oral vaccination protected as well as intranasal vaccination against intranasal challenge with respect to key indicators: protection from weight loss, protection from increase in lung weight, viral load reduction, and induction of serum IgG antibodies, demonstrating that mucosal protection by both routes of administration was comparable.
  

As previously announced, all hamsters that received two oral doses of Vaxart’s COVID-19 vaccine candidate showed no systemic weight loss, a key indicator of protection against COVID-19 in this animal model. By contrast, the unvaccinated animals lost approximately 9% total weight. Additionally, unvaccinated hamsters had over two times (2x) the relative lung weight of orally vaccinated hamsters, a sensitive indicator of serious disease that correlates with the viral load findings.

“These additional data provide further evidence supporting the efficacy potential of our oral COVID-19 vaccine candidate,” said Andrei Floroiu, chief executive officer of Vaxart. “In addition, we believe that our room-temperature-stable oral tablet vaccine would be a more convenient, more practical solution to the COVID-19 pandemic as compared to cold-chain dependent injectable vaccines.”

The study evaluated Vaxart’s recombinant adenoviral vaccine, with doses administered at 0 and 4 weeks. Animals were challenged with SARS-CoV-2 at week 8. Hamsters are considered an excellent model for assessing COVID-19 infection since they can be infected via the intranasal route, and, if infected, they demonstrate clinical symptoms such as weight loss, labored breathing and ruffled fur. Furthermore, hamsters also develop lung issues similar to those seen in humans. Images of hamsters infected with SARS-CoV-2 reveal severe lung injury comparable to what has been observed in infected human lungs, including severe, multi-lobular ground glass opacity, and regions of lung inflammation.