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

—  Data served as foundation for current vaccine candidate for planned Phase 2 research

—  Vaxart vaccine candidates elicited strong antigen-specific serum IgG and IgA with neutralizing activity against multiple variants of concern

—  Vaccination reduced SARS-CoV-2 shedding following infectious challenge in both the upper and lower airway of non-human primates

SOUTH SAN FRANCISCO, Calif., Feb. 05, 2024 (GLOBE NEWSWIRE) -- Vaxart, Inc. (Nasdaq: VXRT) today 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.