A study to assess the immune response and safety of a vaccine against influenza in adults 18 years of age and older.

Overview

Sponsor-declared trial summary

Key facts

Sponsor

GlaxoSmithKline Biologicals

Participant type

Healthy volunteers

Age range

18-64 years, 65+ years

Gender

Male and Female

Therapeutic area

Diseases [C] - Virus Diseases [C02]

Trial duration

completed 10 Sep 2025

Decision date (initial)

2025-09-09

Transition trial

No

Low-intervention

No

Rare-disease indication

No

Vulnerable population

No

Trial design

CTIS Part I — objectives, methods, condition coding

Main objective

Scope: Prophylaxis

To evaluate the humoral immune response induced by the study interventions.
To evaluate the safety and reactogenicity profile of the study interventions.

Secondary objectives 1

1. To evaluate the humoral immune response induced by the study interventions.

Conditions and MedDRA coding

Influenza, Human

Study design 1 period

Eligibility criteria

Principal inclusion / exclusion criteria as submitted by sponsor

Inclusion criteria 7

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. (except for certain states in the US, where only adults as per local regulations will be eligible).
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: o Has practiced adequate contraception for at least 4 weeks prior to the study intervention administration, and o Has a negative urine pregnancy test within 24 hours prior to the study intervention administration, and o Has agreed to continue adequate contraception (Table 26) for at least 8 weeks after study intervention administration.
7. Body mass index (BMI) ≥18 kg/m² and ≤33 kg/m².

Exclusion criteria 25

1. Where applicable, FDA toxicity grades will be exclusionary.
2. Current or chronic history of liver disease or known hepatic or biliary abnormalities (with the exception of Gilbert's syndrome or asymptomatic gallstones).
3. Any confirmed or suspected immunosuppressive or immunodeficient condition, based on medical history and physical examination (no laboratory testing required). HIV-infected individuals may be enrolled if they have been stable on antiretroviral therapy for the past 6 consecutive months, i.e., their treatment has not been modified, their CD4 cell count is ≥ 200/mm³ and their viral load has been undetectable (i.e., HIV-RNA < 50 copies/mL).
4. History of Guillain-Barré Syndrome within 6 weeks of receiving any vaccine.
5. 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).
6. Hypersensitivity to latex.
7. History of any reaction or hypersensitivity likely to be exacerbated by any component of the study intervention(s).
8. History of hypersensitivity or severe allergic reaction to any previous influenza vaccine.
9. History of hypersensitivity or severe allergic reaction to any previous mRNA vaccine.
10. History of or current suspicion of myocarditis or pericarditis (including following administration of an mRNA vaccine); or idiopathic cardiomyopathy, or presence of any medical condition that increases the risk of myocarditis or pericarditis, including cocaine abuse, cardiomyopathy, endomyocardial fibrosis, Hyper Eosinophilic Syndrome (HES), hypersensitivity myocarditis, eosinophilic granulomatosis with polyangiitis and persistent myocardial infection.
11. Condition that in the judgment of the investigator would make intramuscular injection unsafe.
12. 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.
13. History of confirmed influenza infection by local health authority-approved testing methods within 180 days prior to study intervention administration.
14. 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.
15. 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.
16. 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.
17. 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.
18. Chronic administration of immune-modifying drugs (defined as more than 14 consecutive days in total) and/or planned use of long-acting immune-modifying treatments at any time up to the end of the study. Up to 90 days prior to the study intervention administration: o For systemic corticosteroids, this will mean prednisone equivalent ≥20 mg/day for adult participants for >14 days. Inhaled, intra-articular/intra-bursal, and topical corticosteroids are allowed. o Long-acting immune-modifying drugs including among others immunotherapy (e.g., TNF-inhibitors), monoclonal antibodies, antitumoral medication.
19. 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.
20. Administration of anti-tumoral medication during the period starting 90 days before the study intervention or planned administration during the study period.
21. 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.
22. Any study personnel or their immediate dependents, family, or household members.
23. 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.
24. Participant is pregnant.
25. Participant is breastfeeding or will (re)start breastfeeding during the study.

Endpoints

Primary and secondary outcome measures (English text)

Primary endpoints 10

1. Primary end points 1 • Antigen 1 antibody titer at Day 29
2. • Fold increase in antigen 1 antibody titer from Day 1 to Day 29
3. • Antigen 1 antibody seroconversion from Day 1 to Day 29
4. • Antigen 1 antibody seroprotection at Day 1 and Day 29
5. Primary end points 2 • Occurrence of solicited administration site or systemic events with onset within 7 days of study intervention
6. • Occurrence of unsolicited AEs within 28 days of study intervention
7. • Occurrence of SAEs within 6 months of study intervention
8. • Occurrence of AESIs within 6 months of study intervention
9. • Occurrence of MAAEs within 6 months of study intervention
10. • Occurrence of any laboratory abnormalities pre-dose (Day 1), post-Dose (Day 3, Day 8, Day 29)

Secondary endpoints 3

1. Secondary end points 1 - • Antigen 2 antibody titer at Day 29
2. • Fold increase in antigen 2 antibody titer from Day 1 to Day 29
3. • Antigen 2 antibody seroconversion from Day 1 to Day 29

Investigational products

Investigational medicinal products (IMPs), comparators, placebo, auxiliary

Test 2

Comparator 3

Sponsors and contacts

Sponsor organisations, regulatory contacts, third parties

GlaxoSmithKline Biologicals

Sponsor organisation

GlaxoSmithKline Biologicals

Address

Rue De L'Institut 89

City

Rixensart

Postcode

1330

Country

Belgium

Scientific contact point

Organisation

GlaxoSmithKline Biologicals

Contact name

EU GSK Clinical Trials Call Center

Public contact point

Organisation

GlaxoSmithKline Biologicals

Contact name

EU GSK Clinical Trials Call Center

Third parties 9

Locations

1 EU/EEA country · 2 investigational sites

By country

Investigational sites

Results and documents

Annex IV summary of results, Annex V layperson summary, and all documents registered in CTIS for this trial

Documents 72 files

Public protocol annexes, IB summaries, regulatory submissions and post-authorisation documents registered in CTIS.

Application history

1 submissions — initial application plus substantial / non-substantial modifications