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The results of the phase 2 trial were presented to the Annual meeting of the 2018 identification week in San Francisco, California, this week by researchers at Vaxart, Inc., the clinical-stage biotechnology company that developed the tablet, which was made using conventional recombination techniques rather than eggs.
"According to recent studies, the common practice of growing influenza vaccine in chicken eggs may make the influenza vaccine less effective in humans," said David Liebowitz, MD. recent statement. "Our vaccines are not vulnerable to this problem."
For the Phase 2 clinical trial, the researchers compared the efficacy of recombinant adenovirus-expressing haemagglutinin (HA) vaccine from A / California 04/09 with commercial injectable quadrivalent influenza vaccine (VIV).
From 2016 to 2017, participants aged 19 to 49 years were randomized into 3 treatment groups and received either the oral tablet vaccine, an intramuscular placebo-controlled injection, a VQI injection, and a placebo placebo.
Ninety to 120 days after immunization, participants were challenged intranasally with wild-type influenza A H1 virus to determine the efficacy and durability of the vaccine.
The researchers measured changes in HAI titers, microneutralization, and ASC IgA / IgG assays. Exploratory flow cytometry evaluated the quantitative and qualitative aspects of immunogenicity, including markers of activation and localization of the mucosa on B cells, write the authors of the posters.
The analyzes were performed on days 0 and 7 after the immunization of the participants and at 0 and 6 days after their viral exposure. The researchers then isolated plasmablasts sorted from peripheral blood mononuclear cells (PBMCs) for genomic DNA and sequenced them for heavy chain receptor sequencing for the purpose of analysis. next generation sequencing.
According to the investigators, a total of 48% of participants immunized with the oral vaccine tablet were protected against the virus, while only 38% of those immunized with IVIV were protected.
In addition, 37% of people who received the oral tablet vaccine developed an influenza infection, compared with 44% of people who were immunized with QIV and 71% of those who received placebo.
Both vaccines induced a humoral immune response; However, the NGS and FAC analyzes indicated that those who had received the oral tablet had more activated plasmablasts expressing mucosal surface guidance markers and a more diverse B cell population than those who had received VQI.
Overall, researchers postulate that the oral flu tablet is as well protected against infection as IVQ, but the protective mechanism may be unique to the vaccination route.
"Oral immunization allows influenza-specific B cells to be targeted at infection sites and produces a more diverse antibody repertoire," they concluded.
Disclosures:
N. Kolhatkar, Vaxart, Inc .: Employee, Salary; K. Gottlieb, Vaxart, Inc.: employee, salary; K. Kasparek, Vaxart, Inc .: employee, salary; K. Hodgson, Vaxart, Inc .: employee, salary; S. Tucker, Vaxart, Inc .: Employee, Salary; D. Liebowitz, Vaxart, Inc .: Salary, Employee and Investigator.
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