Vaxart, Inc. announced topline data from the approximately 400-participant sentinel safety cohort of its Phase 2b clinical trial evaluating the Company’s oral pill COVID-19 vaccine candidate against an approved mRNA vaccine comparator. Participants in this safety cohort received Vaxart’s oral pill vaccine (201 participants dosed) or an approved mRNA vaccine (199 participants dosed) targeting the XBB strain of SARS-CoV-2, the virus that causes COVID-19. No vaccine-related serious adverse events (SAEs) or sustained Grade 3 or higher adverse events (AEs) were reported in either arm of the study. Data from the complete study, comprising the 400 dosed participants in the sentinel safety cohort and approximately 5,000 dosed participants in the main cohort, are currently anticipated in 2027. Participants in the main cohort received vaccines targeting the KP.2 viral strain prevalent at the time cohort dosing was initiated.

“These topline safety data are encouraging and are consistent with the safety profile observed to date in other studies of our oral pill vaccine constructs,” said James Cummings, MD, Chief Medical Officer at Vaxart. "We know that safety and tolerability are critical factors in successful vaccine development, and we are pleased with how our investigational vaccine performed in this cohort.”

What did the topline 12-month results from the sentinel safety cohort show?
Key topline 12-month results from the 400-participant sentinel safety cohort (201 oral vaccinees and 199 mRNA vaccinees) include:

• No vaccine-related serious adverse events (SAEs) or sustained Grade 3 or higher AEs were reported in either the oral pill vaccine or mRNA arms of the trial.
• The most common AEs in participants receiving the oral pill vaccine were malaise/fatigue (20.9%), headache (18.9%) and anorexia (10.0%). Fewer than 10% of participants experienced any other AE.
• The most common AEs in participants receiving the mRNA vaccine were injection site pain (60.3%), injection site tenderness (40.2%), malaise/fatigue (35.2%), myalgia/muscle pain (33.2%), and headache (28.6%). Arthralgia, chills, anorexia, nausea, diarrhea, and induration/swelling at the injection site were experienced by between 10-15% of participants. Fewer than 10% of participants experienced any other AE.
• With respect to the efficacy measure of symptomatic COVID, 33 participants in Vaxart’s oral pill vaccine arm and 30 participants in the injectable mRNA vaccine arm had symptomatic disease. Asymptomatic COVID cases were reported in 12 participants in the Vaxart oral pill arm and 12 in the mRNA vaccine arm.
  • It should be noted that this 400-participant sentinel safety cohort was not powered to determine comparative efficacy between the two arms.
  • Topline data from the complete study, comprising the 400 participants in the sentinel safety cohort and approximately 5,000 participants in the main cohort, are anticipated in 2027. The main cohort is designed and powered to support the planned statistical comparison of safety and relative efficacy outcomes between the two arms.

“These first cohort topline data are an important advancement for our COVID-19 program and for our oral pill vaccine platform overall,” said Steven Lo, Chief Executive Officer at Vaxart. “This study adds to the body of evidence supporting the safety profile of our vaccine constructs as we look to demonstrate the potential of our proprietary oral delivery technology. We believe more insights into our oral COVID program are important and will be further analyzing this cohort as we eagerly await the readout from the main cohort of this trial, which is expected to provide more robust information on safety and efficacy.”

Funding for this award was received under Project NextGen, an initiative by the Biomedical Advanced Research and Development Authority (BARDA), part of the Administration for Strategic Preparedness and Response (ASPR) in the U.S. Department of Health and Human Services (HHS), and the National Institute of Allergy and Infectious Diseases (NIAID) to accelerate and streamline the development of the next generation of innovative COVID-19 vaccines, therapeutics, and enablers. Vaxart’s project award through the Rapid Response Partnership Vehicle (RRPV) Consortium is valued at up to $344.8 million. This project has been funded in whole or in part with federal funds from the Department of Health and Human Services; Administration for Strategic Preparedness and Response (ASPR); Biomedical Advanced Research and Development Authority (BARDA), under Other Transaction Number: 75A50123D00005.