Vaxart, Inc. a clinical-stage biotechnology company developing oral recombinant vaccines that are administered by tablet rather than by injection, announced publication of the comprehensive results of the previously disclosed Phase 1 clinical trial with its norovirus oral tablet vaccine in the Journal of Clinical Investigation Insight.

Image/CDC
Image/CDC

The paper by Leesun, Kim, et al., “Safety and immunogenicity of an oral tablet norovirus vaccine, a phase 1 randomized, placebo-controlled trial”, highlights the benign safety profile of the Vaxart vaccine and describes the generation of robust systemic and mucosal immune responses, including mucosal IgA, memory B cells, and serum blocking antibody titers (BT50), all potential correlates of protection.

“Our oral tablet vaccine elicited a substantial serum antibody response as well as a strong local intestinal immune response as measured by mucosal homing B-cells and a greater than tenfold increase in fecal IgA antibodies,” said Sean Tucker, Ph.D., founder and chief scientific officer of Vaxart. “Local immunity in the gut is likely to be a key factor in protection against norovirus infection, and this data confirms our vaccine is uniquely positioned to generate this type of response.”

The primary immunological endpoint of the study, an increase in BT50 titers, was met in the high dose group with 78% of subjects showing a greater than or equal to twofold rise after a single immunization (P=0.0003). In addition, more than 80% of recipients of the high dose vaccine developed mucosally-primed norovirus specific circulating antibody secreting cells, IgA positive memory B cells expressing the α4β7 gut homing receptor, and fecal IgA.

“Norovirus causes substantial morbidity and mortality all across the globe, impacting populations of all ages in all walks of life. We believe our tablet vaccine could provide an optimal solution to help reduce the burden of disease in vulnerable populations such as the elderly and the very young, as well as people at-risk in the healthcare, travel and food industry,” said David Taylor, M.D., chief medical officer of Vaxart. “We look forward to initiating our Norovirus vaccine Phase 1 safety and immunogenicity bivalent study and Phase 2 monovalent challenge study in the coming months.”