- Second-generation norovirus constructs produce statistically significant increases in GI.1 and GII.4 norovirus blocking antibodies (141% and 94%, respectively) compared with first-generation constructs, supporting potential for improved protection against infection -

- Vaccine candidates were safe and well-tolerated across all dose groups with no vaccine-related serious adverse events reported -

- Conference call today at 8:30 a.m. ET -

SOUTH SAN FRANCISCO, Calif., June 11, 2025 (GLOBE NEWSWIRE) -- Vaxart, Inc. (NASDAQ:VXRT), a clinical-stage biotechnology company developing a range of oral recombinant pill vaccines based on its proprietary delivery platform, today reported positive topline results from the Phase 1 clinical trial evaluating its second-generation oral pill norovirus vaccine constructs head-to-head against its first-generation constructs.

The open-label, Phase 1 trial was conducted in 60 healthy volunteers who were randomized to receive the first-generation constructs, an equivalent dose of the second-generation GI.1 and GII.4 constructs, or a lower dose of the second-generation constructs (n=20 for each group). The primary immunological endpoint was norovirus blocking antibody assay (NBAA) titer at Day 0 and Day 28. In a Phase 2 challenge trial of the first-generation vaccine constructs, these functional NBAA titers correlated with protection against norovirus infection. Although the study was not powered to determine superiority by statistical methods, the increase in NBAA titers with the second-generation constructs was sufficiently large (141% for the GI.1 construct and 94% for the GII.4 construct) to demonstrate statistical significance at the higher dose.