Vaxart Announces Publication in Vaccines of Non-Human Primate Preclinical Data Demonstrating its Next-Generation Vaccine Candidates Elicit Mucosal & Systemic Immunogenicity & Reduce Viral Shedding After SARS-CoV-2 Challenge

Vaxart, Inc. recently announced the publication of preclinical non-human primate data demonstrating the potential of its COVID-19 vaccine to protect against multiple SARS-CoV-2 variants of concern (VOC)s. The data, which were previously presented at the International Congress of Mucosal Immunology 2022, are reported in the current issue of Vaccines.

“Our preclinical and clinical research laid the foundation for our next steps in testing our SARS-CoV-2 vaccine platform against emerging viral variants,” said Dr. Sean Tucker, Vaxart’s Founder and Chief Scientific Officer. “The data published in Vaccines support the potential of our vaccine platform to stimulate potent mucosal cross-reactive IgA responses to multiple VOCs and reduce viral transmission. We believe this platform has the potential to transform the landscape not only for COVID-19 vaccines, but for other infectious diseases that present significant global public health challenges, such as norovirus and influenza.”

The data included in this publication add to the body of evidence that has guided the clinical development of Vaxart’s COVID-19 oral vaccine program. Vaxart’s preparation for a Phase 2b trial of its COVID-19 XBB vaccine candidate is supported by a recent grant awarded by the United States Biomedical Advanced Research and Development Authority (BARDA).

In the study published in Vaccines, non-human primates were prime-boost immunized 29 days apart with vaccine candidates either expressing the parental spike protein alone (Wuhan-S), spike plus nucleocapsid (Wuhan-S+N), or the spike protein from the beta variant (beta-S) of SARS-CoV-2. Key findings from the study include:

• All three vaccines elicited strong cross-reactive systemic immunity as evidenced by increases in serum IgG and IgA responses.
• All three vaccines elicited robust cross-reactive nasal and lung IgA following mucosal vaccination.
• All three vaccines induced neutralizing antibodies in both the peripheral and mucosal compartments, which was enhanced with a boost immunization.
• Mucosal administration of the vaccines elicited antigen-specific T-cells.
• Viral replication and infectious particle shedding were significantly reduced in immunized animals after challenge with beta variant SARS-CoV-2.

These results suggest that delivering rAd5 vaccines to a mucosal surface is an alternative immunization approach that may generate both serum and mucosal responses, while protecting against infection and reducing shedding. Vaxart believes these data support the potential for its vaccines to enhance mucosal responses and reduce community transmission, in addition to preventing severe disease. Vaxart has previously shown its room-temperature stable mucosal vaccines are easy to administer, store and distribute, which could support vaccine equity and the effectiveness of global public health responses to the continually evolving COVID-19 pandemic.

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 pills that can be stored and shipped without refrigeration and eliminate the risk of needle-stick injury. Vaxart believes that its proprietary pill 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 pill 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.