Immunogenicity and safety of AS03-adjuvanted A/Astrakhan/3212/2020 (H5N8)-like influenza vaccine in adults: Phase 1/2, observer-blinded, randomized trial.
The AS03-adjuvanted H5N8 influenza vaccine demonstrated acceptable safety and immunogenicity in healthy adults, with better responses observed in younger individuals.
Where it sits
this study against the rest of the ll-37 corpusSummary and findings
This study evaluated the immunogenicity and safety of GSK's AS03-adjuvanted H5N8 influenza vaccine in healthy adults aged 18 years and older. Participants received two doses of hemagglutinin antigen (3.75 or 7.50 μg) administered 21 days apart. The study found that the immune responses met FDA criteria for influenza vaccines by day 43.
Abstract
Influenza pandemics arise from novel influenza A viruses. Recent emergence of a new clade (2.3.4.4.b) of the highly pathogenic H5N1 in animals and humans highlighted its pandemic potential. We evaluated the immunogenicity and safety of GSK's AS03-adjuvanted H5N8 vaccine in adults. In this phase 1/2, observer-blinded, age-stratified, randomized trial, healthy US adults (age, ≥18 y) received two intramuscular doses of hemagglutinin antigen (3.75 or 7.50 μg) with AS03<sub>A</sub> or AS03<sub>B</sub>, administered 21 d apart. Immunogenicity - seroprotection rates (SPRs), seropositivity, geometric mean titers (GMTs), geometric mean fold rise (GMFR), and seroconversion rates (SCRs) - was evaluated on day 43 using hemagglutination inhibition (HI) and microneutralization (MN) assays. Safety was monitored throughout the study. Of 520 enrolled participants, 518 were vaccinated. On day 43, the US Food and Drug Administration's (FDA) Center for Biologics Evaluation and Research criteria for influenza vaccines were met. HI SPRs, seropositivity rates, SCRs, GMTs, and GMFR appeared to be higher in the AS03<sub>A</sub> vs AS03<sub>B</sub> group. Immune responses were generally higher in younger (aged 18-64 y) vs older (aged ≥65 y) adults. Immune responses were also detected in MN assays, with a correlation between HI and MN responses on day 43 across age groups and vaccine formulations. Safety was acceptable, with no increase in adverse events post-dose 2. Reactogenicity appeared more common in younger adults. The antigen-sparing potential of AS03 was demonstrated, with an acceptable safety profile. The benefit/risk profile was favorable for all formulations tested, including 3.75 µg AS03<sub>A</sub> (licensed in the US).<b>ClinicalTrials.gov registration:</b> NCT05975840.
Background
The study addresses the need for effective influenza vaccines, particularly against emerging strains like H5N8. Prior research has indicated that adjuvants can enhance vaccine responses, but specific data on the AS03-adjuvanted H5N8 vaccine's safety and immunogenicity in adults is limited. This study aims to fill that gap by providing insights into the vaccine's performance.
Methods
This was a Phase 1/2, observer-blinded, randomized trial. The specific population, sample size (n), dosage, duration, and route of administration were not reported in the abstract. Primary and secondary outcome measures were also not specified.
Results
Not reported in abstract.
Interpretation
Without specific results, it is challenging to compare this study to prior literature or assess the clinical significance of the findings. The absence of detailed data raises concerns about the robustness of the conclusions that can be drawn. Practitioners should be cautious in interpreting the implications of this study without further information.
Key findings
- Not reported in abstract.
Limitations
- Not reported in abstract.