Vaxart Publishes Clinical Data Suggesting its Oral COVID-19 Pill Vaccine Candidate Induces Long-Lasting Mucosal Immune Responses that are Highly Cross-Reactive
Vaccine-induced mucosal IgA antibody responses persisted for up to 1 year and had a higher neutralizing activity compared with convalescent samples
“One of the most important challenges with current COVID-19 vaccine strategies is that injected vaccines stimulate robust serum antibody responses against the
“Our clinical study results showed that our vaccine candidate stimulates broadly cross-reactive mucosal IgA responses that persist for at least 6 months in most responders, and up to a year in a subset of them following just a single dose. Two key observations in this study were that vaccination induced a similar mucosal IgA response as seen in convalescent subjects, and that the vaccinated subjects appeared to have better neutralizing antibody potential in the mucosa than infected subjects. We are excited to explore these aspects in depth in future studies,” he said.
“These findings support our view that the cross-reactivity of our vaccine candidates’ mucosal immune responses could have a significant impact in the fight against evolving SARS-CoV-2 variants,” Dr.
About the Data
The data reported today are from a phase 1 dose-ranging, open-label clinical trial (NCT04563702) in which the S+N vaccine candidate was evaluated in 35 healthy adult volunteers who tested negative for SARS-CoV-2 by PCR and rapid antigen tests. Subjects received a low dose with a boost at Day 29 or a single low or high dose of the S+N oral tablet vaccine candidate.
Nasal samples were collected and analyzed for SARS-CoV-2-specific IgA. In the study, 46% of subjects had at least a 1.5-fold increase in SARS-CoV-2-specific secretory IgA compared with pre-vaccination levels. In a separate study, nasal and saliva samples were collected from individuals with prior SARS-CoV-2 infection. Analysis of nasal and saliva samples for neutralizing activity (sVNT) against SARS-CoV-2 showed that 50% of the vaccinated subjects had more neutralizing activity than those with prior infections, and this enhanced neutralizing capacity persisted 6 months post vaccination.
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.
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Source: Vaxart, Inc.