Vaxart announces publication of preclinical data on vaccine candidates

Vaxart 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 concerns. The data, which were previously presented at the International Congress of Mucosal Immunology 2022, are reported in the current issue of Vaccines. 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. 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, spike plus nucleocapsid, or the spike protein from the beta variant 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.