AzTrials
AzTrials

Influenza, HumanPhase 2NCT07204964

A Study to Evaluate the Immune Response and Safety of an Influenza Vaccine in Adults 18 Years of Age and Above

A Phase 2 study testing Flu mRNA (Formulation B1), Flu mRNA (Formulation B3) and Flu mRNA(Formulation A) in people with Influenza, Human, run by GlaxoSmithKline at 17 sites in 2 countries.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
Search all trials

Trial summary

The purpose of this study is to assess the reactogenicity, safety and immune response of GlaxoSmithKline's (GSK) messenger RNA (mRNA)-based multivalent seasonal influenza vaccine candidates administered in healthy younger and older adults. Read more about this study

Who is it for?
Ages 18 years and olderHealthy volunteers can take part
Conditions the study is for
Influenza, Human
What is being tested?
Flu mRNA (Formulation B1), Flu mRNA (Formulation B3) and Flu mRNA(Formulation A)
Type of treatment
Injection or infusion
Could I receive a placebo?
No, everyone receives an active treatment
How many people
971 participants
Where
17 sitesin 2 countries
Study dates
7 Oct 2025to 24 Aug 2026
Phase
Phase 2
Are there results?
None posted in the registry

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 years and older
  • All sexes
  • Healthy volunteers accepted
  • Adult, Older adult

Who may be able to join

  • 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.
  • Written (physically, or digitally) informed consent obtained from the participant prior to performance of any study-specific procedure.
  • A male or female at least 18 YOA at the time of the screening.
  • 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.
  • Female participants of non-childbearing potential may be enrolled in the clinical study.
  • Female participants of childbearing potential may be enrolled in the clinical study, if the participant:
Show all 10Show fewer
  • 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.
  • Body mass index (BMI) between18 kg/m^2 and 33kg/m^2.

Who cannot join

  • Where applicable, FDA toxicity grades will be exclusionary.
  • Current or chronic conditions related with EXC criteria 1.
  • Immunosuppressive or immunodeficient conditions by history/exam; stable HIV-positive individuals on therapy can participate.
  • History of Guillain-Barré Syndrome within 6 weeks of receiving any vaccine.
  • 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).
  • Hypersensitivity to latex.
Show all 25Show fewer
  • History of any reaction or hypersensitivity likely to be exacerbated by any component of the study interventions.
  • History of hypersensitivity or allergic reaction to any previous influenza vaccine.
  • History of hypersensitivity or allergic reaction to any previous mRNA vaccine.
  • History of or current suspicion of myocarditis or pericarditis or medical condition increasing such risks.
  • Condition that in the judgment of the investigator would make intramuscular injection unsafe.
  • 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.
  • History of confirmed influenza infection by local health authority-approved testing methods within 180 days prior to study intervention administration.
  • 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.
  • 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.
  • 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.
  • 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
  • Chronic administration of immune-modifying drugs.
  • 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.
  • Administration of antitumoral medication during the period starting 90 days before the study intervention or planned administration during the study period.
  • 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.
  • Any study personnel or their immediate dependents, family, or household members.
  • 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.
  • Participant is pregnant.
  • Participant is breastfeeding or will (re)start breastfeeding during the study.

Trial locations and contacts

17 sites in 2 countries.

17 sites in 2 countries

United States15 sites

  • GSK Investigational Site

    Austin, Texas, 78705

  • GSK Investigational Site

    Canoga Park, California, 91303

  • GSK Investigational Site

    Carson City, Nevada, 89706

  • GSK Investigational Site

    Garland, Texas, 75043

  • GSK Investigational Site

    Greensboro, North Carolina, 27408

  • GSK Investigational Site

    Guntersville, Alabama, 35976-2206

  • GSK Investigational Site

    Hialeah, Florida, 33012

  • GSK Investigational Site

    Las Vegas, Nevada, 89109

  • GSK Investigational Site

    Miami, Florida, 33186

  • GSK Investigational Site

    Newport News, Virginia, 23606

  • GSK Investigational Site

    North Charleston, South Carolina, 29405

  • GSK Investigational Site

    Pembroke Pines, Florida, 33025

  • GSK Investigational Site

    Seattle, Washington, 98104-2725

  • GSK Investigational Site

    Stockbridge, Georgia, 30281

  • GSK Investigational Site

    Walnut Creek, California, 94598

Other trials in United States

Belgium2 sites

  • GSK Investigational Site

    Edegem, 2650

  • GSK Investigational Site

    Ghent, Oost-Vlaanderen, 9000

Other trials in Belgium

About this study

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

The purpose of this study is to assess the reactogenicity, safety and immune response of GlaxoSmithKline's (GSK) messenger RNA (mRNA)-based multivalent seasonal influenza vaccine candidates administered in healthy younger and older adults.

Being tested
Flu mRNA (Formulation B1), Flu mRNA (Formulation B3), Flu mRNA(Formulation A), Comparator 1, Comparator 2
Keywords
Influenza, Human, Virus Diseases, Infections, mRNA vaccine, Younger Adults, Older Adults, multivalent seasonal influenza vaccine
Medical subject headings
Influenza, Human, Virus Diseases, Infections

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • Flu mRNA (Formulation B1)Biological

    Also called GSK6498032A

    One dose of Flu mRNA (Formulation B1) received intramuscularly.

  • Flu mRNA (Formulation B3)Biological

    Also called GSK6498032A

    One dose of Flu mRNA (Formulation B3) received intramuscularly.

  • Flu mRNA(Formulation A)Biological

    Also called GSK6479720A

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

  • Comparator 1Combination product

    One dose of Comparator 1 received intramuscularly.

  • Comparator 2Combination product

    One dose of Comparator 2 received intramuscularly.

  • Comparator 3Combination product

    One dose of Comparator 3 received intramuscularly.

Study groups in NCT07204964
Study groupRoleWhat they receive
Flu mRNA_1_YAExperimentalEligible Younger Adults (YA) participants receive a single dose of Flu mRNA Formulation B1 (GSK6498032A) as study intervention at Day 1.
Receives: Biological: Flu mRNA (Formulation B1)
Flu mRNA_3_YAExperimentalEligible YA participants receive a single dose of Flu mRNA Formulation B3 (GSK6498032A) as study intervention at Day 1.
Receives: Biological: Flu mRNA (Formulation B3)
Flu mRNA_4_YAExperimentalEligible YA participants receive a single dose of Flu mRNA Formulation A (GSK6479720A) as study intervention at Day 1.
Receives: Biological: Flu mRNA(Formulation A)
Comparator_1_YAActive comparatorEligible YA participants receive a single dose of comparator 1 at Day 1.
Receives: Combination Product: Comparator 1
Comparator_2_YAActive comparatorEligible YA participants receive a single dose of comparator 2 at Day 1.
Receives: Combination Product: Comparator 2
Flu mRNA_1_OAExperimentalEligible Older Adults (OA) participants receive a single dose of Flu mRNA Formulation B1 (GSK6498032A) as study intervention at Day 1.
Receives: Biological: Flu mRNA (Formulation B1)
Flu mRNA_3_OAExperimentalEligible YA participants receive a single dose of Flu mRNA Formulation B3 (GSK6498032A) as study intervention at Day 1.
Receives: Biological: Flu mRNA (Formulation B3)
Flu mRNA_4_OAExperimentalEligible YA participants receive a single dose of Flu mRNA Formulation A (GSK6479720A) as study intervention at Day 1.
Receives: Biological: Flu mRNA(Formulation A)
Comparator_1_OAExperimentalEligible OA participants receive a single dose of comparator 1 at Day 1.
Receives: Combination Product: Comparator 1
Comparator_2_OAActive comparatorEligible OA participants receive a single dose of comparator 3 at Day 1.
Receives: Combination Product: Comparator 3

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Geometric Mean Titer (GMT) Of Antigen 1 Titer

    Measured: At Day 29

  2. Geometric Mean Increase (GMI) of Antigen 1 Titer

    Measured: From Day 1 to Day 29

  3. Percentage of Participants with Antigen 1 Seroconversion Rate (SCR)

    Measured: From Day 1 to Day 29

  4. Percentage of Participants with Antigen 1 Seroprotection Rate (SPR)

    Measured: At Day 1 and Day 29

  5. Number of Participants with Solicited Administration Site Adverse Events (AEs)

    The solicited administration site AEs considered are pain, redness, swelling and lymphadenopathy.

    Measured: From Day 1 to Day 7

  6. Number of Participants with Solicited Systemic AEs

    The 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.

    Measured: From Day 1 to Day 7

  7. Number of Participants with Unsolicited AEs

    An 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.

    Measured: From Day 1 to Day 28

  8. Number of Participants with Serious Adverse Events (SAEs)

    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.

    Measured: From Day 1 to Day 181 (study end)

  9. Number of Participants with Adverse Events of Special Interest (AESIs)

    Measured: From Day 1 to Day 181 (study end)

  10. Number of Participants with Medically Attended Adverse Events (MAAEs)

    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.

    Measured: From Day 1 to Day 181 (study end)

  11. Number of Participants with any Laboratory abnormalities

    Measured: From Day 1 to Day 29

Secondary outcomes (3)

  1. GMT Ratio of Antigen 2 Titer

    Measured: At Day 29

  2. GMI of Antigen 2 Titer

    Measured: From Day 1 to Day 29

  3. Percentage of Participants with Antigen 2 SCR

    Measured: From Day 1 to Day 29

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted3 Oct 2025
  2. Study start7 Oct 2025
  3. Primary completion24 Aug 2026
  4. Study completion24 Aug 2026

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase 2
Primary purpose
Prevention
Allocation
Randomised
Intervention model
Parallel groups
Masking
Quadruple blind
Who is masked
Participant, Care provider, Investigator, Outcomes assessor
Enrolment
971 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT07204964
Sponsor's protocol ID
300336
Other IDs
2025-522599-97-00, 2025
Status last verified
Sep 2026
First submitted
1 Oct 2025
Last updated
18 Sep 2026
Results posted
No
Data monitoring committee
No
FDA-regulated drug
Yes
FDA-regulated device
No
Individual data sharing
Yes: Study Sponsor will assess requests from qualified researchers for anonymized individual patient-level data and related study documents. Data sharing is subject to certain criteria, conditions, and exceptions. For further information, refer to https://www.gsk-studyregister.com/About\_GSK\_Patient\_Level\_Data\_Sharing\_Final\_13July2023.pdf

Questions about this trial

What is this clinical trial studying?

A Phase 2 study testing Flu mRNA (Formulation B1), Flu mRNA (Formulation B3) and Flu mRNA(Formulation A) in people with Influenza, Human, run by GlaxoSmithKline at 17 sites in 2 countries.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 10 inclusion and 25 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 18 Sep 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 17 sites in United States, Belgium. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Geometric Mean Titer (GMT) Of Antigen 1 Titer (time frame: At Day 29). The study lists 11 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT07204964.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 18 Sep 2026.

AzTrials uses cookies for analytics and advertising. You can accept or reject them; the site works either way. Privacy Policy.

Free account

Log in to keep searching

You’ve used your 3 free searches. AzTrials is free: log in or create a free account to keep searching clinical trials and save the ones you want to follow.

Create a free accountLog in