SOUTH SAN FRANCISCO, Calif., Oct. 14, 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 the topline results from its Hamster Challenge Study. The available results show that all hamsters that received two oral doses of COVID-19 vaccine candidate showed no systemic weight loss, a key indicator of protection against COVID-19 in this animal model.
"Our oral vaccine showed that 100% of hamsters receiving two oral doses of vaccine in the study were protected against systemic weight loss, as well as lung weight gain, which is a key indicator of lung damage due to infection," said Sean Tucker, Ph.D., chief scientific officer, and founder of Vaxart. "Given that the hamster is a great model for assessing severe infection, this study helps to validate our vaccine's potential to provide potent protection against COVID-19. These results increase our confidence as we move our vaccine candidate into human clinical trials."
The study evaluated Vaxart's recombinant adenoviral vaccine, with doses given at 0 and 4 weeks. Animals were challenged with SARS-CoV-2 at week 8. Topline data demonstrated that all unvaccinated animals lost at least 8% of their body weight, and all showed evidence of lung disease as measured by relative weight gain in the lungs. By contrast, all animals vaccinated with two doses of the oral vaccine maintained or gained body weight by the end of the experiment, a statistically significant result (p<0.001). Additionally, these animals were protected against the lung weight gain seen in the unvaccinated animals (p<0.001). For unvaccinated animals, lung weight as a percentage of body weight was approximately twice that of the animals that received two oral doses of the vaccine. The experiment was designed to monitor systemic weight for 5 days before animals were assessed for lung disease. N=8 per group. Hamsters receiving one oral dose had partial protection. Full results from the study will be published when data analysis is complete.
"We are happy that just as we dosed the first human subjects in our Phase 1 clinical trial, we showed indicators of protection against COVID-19 in an animal challenge study. These results support the efficacy potential of our oral COVID-19 vaccine candidate suggested by our earlier pre-clinical data," said Andrei Floroiu, chief executive officer of Vaxart. "We believe that our oral vaccine can be an important global solution for the COVID-19 pandemic, given its more convenient route of administration and supply chain distribution as compared to cold chain dependent injectable vaccines."
Hamsters provide a very sensitive model for assessing COVID-19 infection since they can be infected via the intranasal route, and, if infected, they demonstrate pronounced clinical symptoms such as weight loss. They can also show signs such as labored breathing and ruffled fur. They also develop lung issues similar to those seen in humans. Images of hamsters infected with SARS-CoV-2 reveal severe lung injury similar to that seen in infected human lungs, including severe, multi-lobular ground glass opacity, and regions of lung inflammation and consolidation.