Vaxart's Oral Vaccine For Stomach Bug Shows Reduction In Infection Rate

Vaxart Inc VXRT released topline data from the Phase 2 challenge study of its oral tablet monovalent norovirus vaccine candidate.

In July, the company released interim data.

Norovirus is a very contagious virus that causes vomiting and diarrhea. Anyone can get infected and sick with norovirus. Norovirus is sometimes called the "stomach flu" or "stomach bug.

The Phase 2 challenge study enrolled 165 healthy adults. Four weeks after vaccination, subjects were challenged with GI.1 norovirus. 

The study achieved its primary endpoint of a statistically significant 29% reduction in the rate of norovirus infection between the vaccinated and placebo arms through Day 8 post-challenge (82% vs. 58%) (p=0.003). 

21% reduction in the rate of norovirus acute gastroenteritis (AGE) in the vaccinated cohort compared with placebo (45% vs. 57%) that was not statistically significant (p=0.149).

In a prespecified analysis, the study also showed an 85% decrease in viral shedding in the vaccine arm compared with placebo.

There was a significant increase in the induction of norovirus-specific IgA antibody-secreting cells (ASC) in the vaccinated cohort, with a 79% response rate compared with 2.5% in the placebo cohort.

In a prespecified analysis, the study also showed an 85% decrease in viral shedding in the vaccine arm compared with placebo. There was no statistically significant difference in disease severity in the vaccinated cohort compared with the placebo.

No vaccine-related SAEs or dose-limiting toxicities were reported, consistent with the safety profile observed in Vaxart's norovirus trials.

Vaxart is currently conducting additional analyses of the data from this challenge study and its prior norovirus trials to define the timing of a larger Phase 2b study and identify ways to reduce the size and duration of a subsequent Phase 3 registration study.

Price Action: VXRT shares are down 6.56% at $0.75 on the last check Thursday.