Last updated: 11/12/2025 13:50:10
A Study to Assess the Immune Response and Safety of a Vaccine Against Influenza in Adults 18 Years of age and Older
GSK study ID
300356
Clinicaltrials.gov ID
EudraCT ID
EU CT Number
Not applicable
Trial status
Recruitment complete
Recruitment complete
Trial overview
Official title: A Phase 2a Randomized, Observer-Blind, Study to Evaluate the Immunogenicity and Safety of mRNA-Based Multivalent Seasonal Influenza Vaccine Candidates in Adults 18 Years of age And Older
Trial description: "The purpose of this study is to assess the reactogenicity, safety and immune response of GlaxoSmithKlines (GSK) messenger RNA (mRNA)-based multivalent seasonal influenza vaccine candidates administered in healthy younger and older adults."
Primary purpose:
Prevention
Trial design:
Parallel
Masking:
Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Allocation:
Randomized
Primary outcomes:
Geometric Mean Titer (GMT) Ratio of Antigen 1 Titer
Timeframe: At Day 29
Geometric Mean Increase (GMI) of Antigen 1 Titer
Timeframe: From Day 1 to Day 29
Percentage of Participants with Antigen 1 Seroconversion Rate (SCR)
Timeframe: From Day 1 to Day 29
Percentage of Participants with Antigen 1 Seroprotection Rate (SPR)
Timeframe: At Day 1 and Day 29
Number of Participants with Solicited Administration Site Adverse Events (Aes)
Timeframe: From Day 1 to Day 7
Number of Participants with Solicited Systemic Aes
Timeframe: From Day 1 to Day 7
Number of Participants with Unsolicited Aes
Timeframe: From Day 1 to Day 28
Number of Participants with Serious Adverse Events (SAEs)
Timeframe: From Day 1 to Day 181 (study end)
Number of Participants with Adverse Events of Special Interest (AESIs)
Timeframe: From Day 1 to Day 181 (study end)
Number of Participants with Medically Attended Adverse Events (MAAEs)
Timeframe: From Day 1 to Day 181 (study end)
Number of Participants with any Laboratory abnormalities
Timeframe: From Day 1 to Day 29
Secondary outcomes:
GMT Ratio of Antigen 2 Titer
Timeframe: At Day 29
GMI of Antigen 2 Titer
Timeframe: From Day 1 to Day 29
Percentage of Participants with Antigen 2 SCR
Timeframe: From Day 1 to Day 29
Interventions:
Enrollment:
776
Primary completion date:
2026-15-05
Observational study model:
Not applicable
Time perspective:
Not applicable
Clinical publications:
Not applicable
Medical condition
Influenza, Human
Product
Not applicable
Collaborators
Not applicable
Study date(s)
August 2025 to May 2026
Type
Interventional
Phase
2
Participation criteria
Sex
Female & Male
Age
18+ years
Accepts healthy volunteers
Yes
- 1. Participants, who, in the opinion of the investigator, can and will comply with the requirements of the protocol (e.g., completion of the eDiary, attendance to study contacts and study site visits, and ability to access and utilize a phone or other electronic communications) independently or with the assistance of a caregiver.
- 2. Written (physically, or digitally) informed consent obtained from the participant prior to performance of any study-specific procedure.
- 1. Where applicable, FDA toxicity grades will be exclusionary.
- 2. Immunosuppressive or immunodeficient conditions by history/exam; stable HIV-positive individuals on therapy can participate.
Inclusion and exclusion criteria
Inclusion criteria:
- 1. Participants, who, in the opinion of the investigator, can and will comply with the requirements of the protocol (e.g., completion of the eDiary, attendance to study contacts and study site visits, and ability to access and utilize a phone or other electronic communications) independently or with the assistance of a caregiver. 2. Written (physically, or digitally) informed consent obtained from the participant prior to performance of any study-specific procedure. 3. A male or female at least 18 YOA at the time of the screening. 4. Healthy participants or medically stable patients as established by medical history, and clinical examination. Participants with chronic medical conditions with or without specific treatment (e.g., chronic metabolic, cardiac, pulmonary, renal, neurologic, and hematologic diseases) are allowed to participate in this study, if considered by the investigator as medically stable. A stable medical condition is defined as disease not requiring significant change in therapy or hospitalization for worsening disease during 3 months before enrollment. 5. Female participants of non-childbearing potential may be enrolled in the clinical study. 6. Female participants of childbearing potential may be enrolled in the clinical study, if the participant: − Has practiced adequate contraception for at least 4 weeks prior to the study intervention administration, and − Has a negative urine pregnancy test within 24 hours prior to the study intervention administration, and − Has agreed to continue adequate contraception for at least 8 weeks after study intervention administration. 7. Body mass index (BMI) between18 kg/m^² and 33kg/m^².
Exclusion criteria:
- 1. Where applicable, FDA toxicity grades will be exclusionary. 2. Immunosuppressive or immunodeficient conditions by history/exam; stable HIV-positive individuals on therapy can participate. 3. History of Guillain-Barré Syndrome within 6 weeks of receiving any vaccine. 4. Significant underlying illness that in the opinion of the investigator would be expected to prevent completion of the study (e.g., life-threatening disease likely to limit survival to less than 1 year). 5. Hypersensitivity to latex. 6. History of any reaction or hypersensitivity likely to be exacerbated by any component of the study intervention(s). 7. History of hypersensitivity or severe allergic reaction to any previous influenza vaccine. 8. History of hypersensitivity or severe allergic reaction to any previous mRNA vaccine. 9. History of or current suspicion of myocarditis or pericarditis, or medical issues increasing such risks. 10. Condition that in the judgment of the investigator would make intramuscular injection unsafe. 11. Any other clinical condition that, in the opinion of the investigator, might pose additional risk to the participant due to participation in the clinical study. 12. History of confirmed influenza infection by local health authority-approved testing methods within 180 days prior to study intervention administration. 13. Use of any investigational or non-registered product (drug, vaccine or invasive medical device) other than the study intervention(s) during the period beginning 28 days before the dose of study intervention(s) (Day -28 to Day 1), or their planned use during the study period. 14. Administration of an influenza vaccine within 180 days before the study intervention administration or planned administration prior to Visit 4 (Day 29) during the study. 15. Administration of any non-live attenuated non-study vaccine in the period starting 14 days before the study intervention administration, or planned administration within 14 days after study intervention administration. 16. Administration of any live attenuated and/or mRNA non-study non-influenza vaccine in the period starting 28 days before the study intervention administration, or planned administration within 28 days after study intervention administration. 17. Chronic administration of immune-modifying drugs. 18. Administration of immunoglobulins and/or any blood products or plasma derivatives during the period starting 90 days before the study intervention, or planned administration during the study period. 19. Administration of anti-tumoral medication during the period starting 90 days before the study intervention or planned administration during the study period. 20. Concurrently participating in another clinical study, at any time during the study period, in which the participant has been or will be exposed to an investigational or a non-investigational intervention. 21. Any study personnel or their immediate dependents, family, or household members. 22. Has a history of chronic alcohol consumption and/or drug abuse as deemed by the investigator to render the potential participant unable/unlikely to provide accurate safety reports or comply with study procedures. 23. Participant is pregnant. 24. Participant is breastfeeding or will (re)start breastfeeding during the study.
Trial location(s)
Location
GSK Investigational Site
Austin, TX, United States, 78705
Status
Recruitment Complete
Location
GSK Investigational Site
Fort Worth, TX, United States, 76135
Status
Recruitment Complete
Location
GSK Investigational Site
Hialeah, FL, United States, 33012
Status
Recruitment Complete
Location
GSK Investigational Site
Jupiter, FL, United States, 33458
Status
Recruitment Complete
Location
GSK Investigational Site
Lenexa, KS, United States, 66219
Status
Recruitment Complete
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Study documents
No study documents available.
Results overview
Study Results yet to be posted
Recruitment status
Recruitment complete
Actual primary completion date
Not applicable
Actual study completion date
Not applicable
Plain language summaries
Plain language summaries of clinical trial results for Phase 2-4 clinical trials that were initiated on or after January 2022 will be posted by GSK within one year following study completion.
Additional information about the trial
Additional information
Not applicable
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