Vaxart Touts Encouraging Positive Preliminary Data From Bivalent Norovirus Vaccine Study

Vaxart Inc VXRT announced topline data from the dose-ranging Phase 2 trial of its oral pill bivalent norovirus vaccine candidate.

Norovirus causes acute viral gastroenteritis. There are no approved vaccines for noroviruses. In the U.S. alone, the annual disease burden from norovirus is $10.6 billion, which causes 19 to 21 million cases of acute gastroenteritis, infecting 15% of all children under five years.

Preliminary trial results showed strong serum immune responses across all doses at Day 29 relative to Day 1. 

Both doses showed a similar increase in serum antibody responses with no statistical difference between the medium and high dose arms. At Day 29, increases in serum IgA, IgG, and BT50, for the GII.4 and GI.1 strains in the vaccine arms were similar to those seen in previous norovirus studies conducted by Vaxart. 

Results from this Phase 2 dose-ranging study also demonstrated that the bivalent norovirus vaccine candidate was well tolerated, with a favorable safety profile that included no vaccine-related serious adverse events (SAEs) and no dose-limiting toxicity. 

Adverse event rates for both doses were similar to placebo.

The company says the final results could vary slightly from these preliminary data, and additional timepoint measures and mucosal data are expected in 2H of 2023.

Vaxart says the above data and upcoming topline data from the ongoing Phase 2 G1.1 challenge study will inform dosage amounts for a bivalent norovirus Phase 2b study, the next step in progressing the vaccine candidate.

The Phase 2b study is expected to add safety data that, if successful, will then enable Vaxart to schedule an End-of-Phase 2 meeting with the FDA, potentially in 2024. 

Price Action: VXRT shares are down 3.11% at $0.70 on the last check Thursday.