Vaxart Doses First Subject in the Phase 2 Clinical Trial of its Bivalent Norovirus Candidate

Vaxart, Inc. recently announced it has dosed the first subject in the Phase 2 clinical trial of its oral tablet bivalent norovirus candidate. The dose-ranging study is designed to identify a vaccine dose for a potential Phase 3 clinical trial.

“Initiating the Phase 2 clinical trial of this candidate is an important achievement toward our goal of developing an oral tablet vaccine that may reduce the significant global health threat that norovirus poses to children and seniors,” said Dr. James F. Cummings, MD, Chief Medical Officer at Vaxart. “Results from the Phase 1b clinical trial in healthy adults demonstrate that this candidate stimulates robust IgA antibody secreting cells against the prevalent strains of two norovirus genotypes that cause the majority of norovirus disease. Data from the Phase 2 trial will inform our further clinical development strategy for this promising vaccine candidate targeting a market estimated at more than $10 billion in the US alone.”

As previously reported, Vaxart’s bivalent vaccine candidate demonstrated robust immunogenicity, with an IgA ASC response rate of 78% for the GI.1 strain and 93% for the GII.4 strain, with no interference observed.

This Phase 2 clinical trial is expected to enroll approximately 135 healthy adults at three sites in the US. The first 10 subjects will receive open label high-dose vaccine and the remaining subjects will be randomized to high- or low-dose vaccine (N=50 for each arm) or placebo (N=25). The primary endpoints are safety and immunogenicity with the objective of determining dose levels for Phase 3 development.

Vaxart expects to report topline data from the Phase 2 study in mid-2023.

Norovirus imposes significant health and economic burdens, with an estimated global impact of $60 billion. In the US, norovirus causes 21 million illnesses each year, infecting 15% of all children under the age of 5 years and resulting in illness — which frequently requires hospitalization — in 7.5% of people over the age of 65 years. Approximately 3 million sets of parents need to take an average of 2 days off from work to care for children with norovirus illness.

Vaxart’s bivalent norovirus oral tablet candidate is differentiated from other norovirus vaccines in development because it generates both systemic and mucosal immunity, is delivered through the mouth and is stable at room temperature, making it much easier to distribute and administer than injected vaccines.

Vaxart is a clinical-stage biotechnology company developing a range of oral recombinant vaccines based on its proprietary delivery platform. Vaxart vaccines are designed to be administered using pills that can be stored and shipped without refrigeration and eliminate the risk of needle-stick injury. Vaxart believes that its proprietary pill vaccine delivery platform is suitable to deliver recombinant vaccines, positioning the company to develop oral versions of currently marketed vaccines and to design recombinant vaccines for new indications. Vaxart’s development programs currently include pill vaccines designed to protect against coronavirus, norovirus, seasonal influenza, and respiratory syncytial virus (RSV), as well as a therapeutic vaccine for human papillomavirus (HPV), Vaxart’s first immune-oncology indication. Vaxart has filed broad domestic and international patent applications covering its proprietary technology and creations for oral vaccination using adenovirus and TLR3 agonists.