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A Study to Assess the Immune Response and Safety of a Vaccine Against Influenza in Adults 18 Years of Age and Older

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

Status
Completed
Phases
Phase 2
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT07121192
Enrollment
776
Registered
2025-08-13
Start date
2025-08-25
Completion date
2026-05-11
Last updated
2026-05-28

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Influenza, Human

Keywords

Influenza, Human, Virus Diseases, Infections, mRNA vaccine, Younger Adults, Older Adults, multivalent seasonal influenza vaccine

Brief summary

"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."

Interventions

BIOLOGICALFlu mRNA (Formulation A)

One dose of Flu mRNA (Formulation A) received intramuscularly.

BIOLOGICALFlu mRNA (Formulation B)

One dose of Flu mRNA (Formulation B) received intramuscularly.

COMBINATION_PRODUCTComparator 1

One dose of Comparator 1 received intramuscularly.

COMBINATION_PRODUCTComparator 2

One dose of Comparator 2 received intramuscularly.

COMBINATION_PRODUCTComparator 3

One dose of Comparator 3 received intramuscularly.

Sponsors

GlaxoSmithKline
Lead SponsorINDUSTRY

Study design

Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
PREVENTION
Masking
QUADRUPLE (Subject, Caregiver, Investigator, Outcomes Assessor)

Masking description

This is an Observer-blind study.

Eligibility

Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
Yes

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.

Design outcomes

Primary

MeasureTime frameDescription
Geometric Mean Titer (GMT) Ratio of Antigen 1 TiterAt Day 29
Geometric Mean Increase (GMI) of Antigen 1 TiterFrom Day 1 to Day 29
Percentage of Participants with Antigen 1 Seroconversion Rate (SCR)From Day 1 to Day 29
Percentage of Participants with Antigen 1 Seroprotection Rate (SPR)At Day 1 and Day 29
Number of Participants with Solicited Administration Site Adverse Events (Aes)From Day 1 to Day 7The solicited administration site AEs considered are pain, redness, swelling and lymphadenopathy.
Number of Participants with Solicited Systemic AesFrom Day 1 to Day 7The solicited systemic AEs considered are fever, headache, fatigue, myalgia, arthralgia and chills. Fever is defined as temperature greater than or equal to (\>=) 38 °C/100.4°F regardless the location of measurement.
Number of Participants with Unsolicited AesFrom Day 1 to Day 28An unsolicited AE is an AE that was either not included in the list of solicited events or could be included in the list of solicited events but with an onset outside the specified period of follow-up for solicited events.
Number of Participants with Serious Adverse Events (SAEs)From Day 1 to Day 181 (study end)SAE is an AE which results in death, is life-threatening, requires inpatient hospitalization or prolongation of existing hospitalization, results in disability/incapacity, or other situations that are considered serious per medical or scientific judgment.
Number of Participants with Adverse Events of Special Interest (AESIs)From Day 1 to Day 181 (study end)
Number of Participants with Medically Attended Adverse Events (MAAEs)From Day 1 to Day 181 (study end)A MAAE is an AE for which the participant received medical attention including any symptom or illness requiring hospitalization, or an emergency room visit, or visit to/by a healthcare professional.
Number of Participants with any Laboratory abnormalitiesFrom Day 1 to Day 29Click here to enter text.

Secondary

MeasureTime frame
GMT Ratio of Antigen 2 TiterAt Day 29
GMI of Antigen 2 TiterFrom Day 1 to Day 29
Percentage of Participants with Antigen 2 SCRFrom Day 1 to Day 29

Countries

United States

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: May 29, 2026