In short
Clinical trials of A/(H3N2)-LIKE VIRUS ANTIGEN are studying influenza vaccine responses in adults aged 50 years and older. These studies look at immunogenicity, which means how well the vaccine helps the body make antibodies, and safety. The main groups are healthy adults and adults with stable health conditions that raise the risk of influenza complications.
Key points
- A/(H3N2)-LIKE VIRUS ANTIGEN is being studied in a Phase 3 influenza vaccine trial in adults aged 50 years and older. The study includes healthy people and people with stable comorbidities that raise the risk of flu complications. Researchers are mainly measuring immune response, including geometric mean titer, seroconversion rate, and lot-to-lot consistency. The trial also compares the study vaccine with other influenza vaccines. The trial is completed and enrolled 6300 people.
Trial overview
The main study of A/(H3N2)-LIKE VIRUS ANTIGEN was a Phase 3, interventional trial called the Celljuvant study. It was completed and enrolled 6,300 participants.
The study looked at an adjuvanted quadrivalent subunit inactivated cell-derived influenza vaccine and compared immune responses across different vaccine lots and against other influenza vaccine products.
Who participated
The trial studied adults aged 50 years and older. Participants were either healthy or had stable comorbidities, which means other long-term health conditions that increase the risk of flu complications but were not changing quickly.
This target group is important because older adults are more likely to have serious problems from influenza infection.
What was studied
The study first tested lot-to-lot consistency of 3 consecutive vaccine lots of aQIVc HD, meaning the researchers checked whether different batches gave similar immune responses. This helps show that the vaccine is produced consistently.
The trial then tested immunological noninferiority of aQIVc HD versus QIVr and versus aQIV. Noninferiority means the study aimed to show that the immune response was not worse than the comparison vaccines by more than a set amount.
The immune response was measured for each vaccine strain, including the H3N2-related strain listed in the source data as A/DARWIN/9/2021 (H3N2)-LIKE STRAIN.
Study endpoints and measurements
The main endpoints were immunogenicity responses, which means how strongly the body made antibodies after vaccination.
- Day 29 Geometric Mean Titer (GMT): this measures the average antibody level in the group 29 days after vaccination.
- Day 29 Geometric Mean Titer Ratio (GMTr): this compares antibody levels between vaccine lots or study groups.
- Day 1 to Day 29 Seroconversion Rate (SCR): this shows the percentage of people whose antibody levels rose enough to count as a clear immune response.
- SCR difference: this compares the rise in antibody response between study groups.
These results were measured with a hemagglutination inhibition assay, a lab test used to measure influenza antibodies.
Trial phase and design
This was a Phase 3 interventional study, which means participants received study vaccines and the research was done in a large group of people. The study design was sequential: first it checked consistency between vaccine lots, and then it compared immune responses against other influenza vaccines.
The source data also shows that the study included several influenza vaccine components and related strains, which were used to assess immune response across the vaccine’s strains.
Key trial details
- Trial ID: 2023-503763-42-00.
- Status: Completed.
- Population: Adults 50 years and older, including healthy people and people with stable comorbidities.
- Enrollment: 6,300 participants.
- Main focus: Immunogenicity and comparison of vaccine lots and vaccine products.