Vaxart Announces Publication of Complete Data From Preclinical COVID-19 Oral Vaccine Hamster Challenge Study

Vaxart, Inc. recently announced the Journal of Infectious Diseases has published complete data from Vaxart’s preclinical Hamster Challenge Study. The study shows Vaxart’s COVID-19 oral vaccine candidate’s potential efficacy in preventing SARS-CoV-2 infection.

“The complete data from the Hamster Challenge Study, together with Vaxart’s other preclinical and clinical data, reinforce our belief that Vaxart’s vaccine could have a major impact on the fight against COVID-19,” said Dr. Sean Tucker, Vaxart’s Chief Scientific Officer and founder, as well as a co-author of the study.

The Hamster Challenge Study adds to the significant body of preclinical and clinical evidence Vaxart has amassed during the last two years supporting its belief that Vaxart’s room temperature oral tablet COVID-19 vaccine candidate, can be effective against SARS-CoV-2:

• A Hamster Transmission Study, conducted by Duke University and published in bioRxiv last month, demonstrated that the COVID-19 vaccine reduced the airborne transmission of SARS-CoV-2 virus in a hamster model.
• These results are consistent with those from Vaxart’s Phase 2 human flu challenge study, which showed that Vaxart’s oral tablet flu vaccine was better at reducing shedding than the injectable flu vaccine comparator.
• Vaxart’s Phase 1 results, released earlier this year, showed that the vaccine triggered multiple immune responses against SARS-CoV-2 antigens, including strong T-cell and IgA responses.
• Vaxart anticipates its Phase 2 clinical study to provide additional evidence regarding the potential impact and efficacy of the oral tablet COVID-19 vaccine. Initial data from that study is expected in Q1 2022.

Vaxart Senior Scientist Dr. Susan Johnson, the Hamster Challenge Study’s lead author, said “An oral room temperature vaccine that protects against COVID-19 and reduces airborne transmission of SARS-CoV-2 would significantly improve our ability to fight the COVID-19 pandemic not only in the developed world, but could give us a major public heath advantage in less developed countries that do not have the infrastructure to easily transport, store, and administer existing vaccines.”

Key Findings of the Hamster Challenge Study

Key findings from the study include:

• All hamsters that received two doses of the oral vaccine demonstrated protection from COVID-19.
• Vaccinated hamsters had no significant loss of weight over the five days post challenge, while unvaccinated hamsters lost up to 10% of their body weight.
• Lung weight, which can be an indirect measure of lung inflammation, was significantly lower in double-vaccinated hamsters compared with unvaccinated animals.
• Five days post challenge, double-vaccinated hamsters had a greater than 4 log reduction in viral load and had no detectable infectious virus in their lungs.

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 because 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, 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.

Vaxart is a clinical-stage biotechnology company developing a range of oral recombinant vaccines based on its proprietary delivery platform. Vaxart vaccines are designed to be administered using tablets that can be stored and shipped without refrigeration and eliminate the risk of needle-stick injury. Vaxart believes that its proprietary tablet vaccine delivery platform is suitable to deliver recombinant vaccines, positioning the company to develop oral versions of currently marketed vaccines and to design recombinant vaccines for new indications. Vaxart’s development programs currently include tablet vaccines designed to protect against coronavirus, norovirus, seasonal influenza, and respiratory syncytial virus (RSV), as well as a therapeutic vaccine for human papillomavirus (HPV), Vaxart’s first immune-oncology indication. Vaxart has filed broad domestic and international patent applications covering its proprietary technology and creations for oral vaccination using adenovirus and TLR3 agonists.