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Respiratory Syncytial Virus InfectionsPhase 1NCT06573281

A Study on the Safety and Immune Response to an mRNA-based RSV Investigational Vaccine in Healthy Adults Aged 18-45 Years

A Phase 1 study testing Investigational RSV vaccine 1, Investigational RSV vaccine 2 and Investigational RSV vaccine 3 in people with Respiratory Syncytial Virus Infections, run by GlaxoSmithKline at 9 sites in 3 countries.

Completed

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

Official record
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Trial summary

The purpose of this study is to assess the reactogenicity, safety and immune response of various formulations of the RSV mRNA investigational vaccine administered in healthy participants 18-45 years of age. Read more about this study

Who is it for?
Ages 18 to 45 yearsHealthy volunteers can take part
Conditions the study is for
Respiratory Syncytial Virus Infections
What is being tested?
Investigational RSV vaccine 1, Investigational RSV vaccine 2 and Investigational RSV vaccine 3
Could I receive a placebo?
Yes, some participants may receive a placebo
How many people
213 participants
Where
9 sitesin 3 countries
Study dates
30 Sep 2024to 26 Feb 2026
Phase
Phase 1
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 to 45 years
  • All sexes
  • Healthy volunteers accepted
  • 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, return for follow-up visits).
  • Written informed consent obtained from the participant prior to performance of any study-specific procedure.
  • Healthy participants as established by medical history, clinical examination and laboratory assessment at screening.
  • Male or female between and including 18 and 45 years of age at the time of enrollment into the study.
  • Body mass index more than or equal to (>=) 18 kg/m^2 and less than (<) 40 kg/m^2.
  • Female participants of non-childbearing potential may be enrolled in the study.
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  • Female participants of childbearing potential may be enrolled in the study if the participant:
  • has practiced adequate contraception for 1 month prior to study intervention administration period, and
  • has a negative pregnancy test (on urine sample) on the day of study intervention administration, and
  • has agreed to continue adequate contraception during the entire treatment period and for at least 1 month after completion of the study intervention administration series.

Who cannot join

  • Medical conditions
  • History of any reaction or hypersensitivity likely to be exacerbated by any component of the study interventions.
  • Hypersensitivity to latex.
  • Any confirmed or suspected immunosuppressive or immunodeficient condition, based on medical history and physical examination (no laboratory testing required).
  • Acute or chronic clinically significant pulmonary, cardiovascular, hepatic or renal functional abnormality.
  • Recurrent history or uncontrolled neurological disorders or seizures.
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  • Documented HIV, HBV, or HCV-positive participant.
  • Lymphoproliferative disorder or malignancy within 5 years before the first dose of study intervention administration.
  • History of or current suspicion of myocarditis or pericarditis.
  • Prior/Concomitant therapy
  • Use of any investigational or non-registered product (drug, vaccine, or invasive medical device) other than the study intervention during the period beginning 30 days before the first dose of study intervention administration (Day -29 to Day 1), or their planned use during the study period.
  • Has previously received an investigational or approved vaccine or antibody for prevention of RSV infection.
  • Planned administration/administration of a vaccine in the period starting 30 days before the first dose and ending 30 days after the last dose of study intervention administration, except for inactivated vaccines for influenza if they are received at least 14 days before the first dose or 14 days after the last study intervention administration.
  • 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.
  • Prior/Concurrent clinical study experience
  • 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 (drug/invasive medical device).
  • Other exclusion criteria
  • Pregnant or lactating female participant.
  • Female participant planning to become pregnant or planning to discontinue contraceptive precautions within 1 month following the last study intervention administration.
  • Alcoholism or substance use disorder within the past 24 months.
  • Any study personnel or their immediate dependents, family, or household members.
  • Participants with extensive body markings or conditions in the deltoid region that may preclude accurate assessment of local reactogenicity.

Trial locations and contacts

9 sites in 3 countries.

9 sites in 3 countries

United States5 sites

  • GSK Investigational Site

    Atlanta, Georgia, 30281

  • GSK Investigational Site

    Lenexa, Kansas, 66219

  • GSK Investigational Site

    Omaha, Nebraska, 68134

  • GSK Investigational Site

    Rochester, New York, 14609

  • GSK Investigational Site

    Rolling Hills Estates, California, 90274

Other trials in United States

Spain3 sites

  • GSK Investigational Site

    Madrid, 28006

  • GSK Investigational Site

    Madrid, 28046

  • GSK Investigational Site

    Madrid, 28222

Other trials in Spain

Australia1 site

  • GSK Investigational Site

    Camberwell, Victoria, 3124

Other trials in Australia

About this study

Official title: A Phase 1, First-Time-in-Human (FTiH), Observer-blind, Randomized, Controlled Study to Evaluate the Safety, Reactogenicity and Immune Response of Various Doses of an mRNA-based Respiratory Syncytial Virus (RSV) Investigational Vaccine in Healthy Participants 18-45 Years of Age

The purpose of this study is to assess the reactogenicity, safety and immune response of various formulations of the RSV mRNA investigational vaccine administered in healthy participants 18-45 years of age.

Being tested
Investigational RSV vaccine 1, Investigational RSV vaccine 2, Investigational RSV vaccine 3, Investigational RSV vaccine 4, Investigational RSV vaccine 5
Keywords
Respiratory syncytial virus (RSV), RSV mRNA vaccine, Safety, Immunogenicity, Reactogenicity
Medical subject headings
Respiratory Syncytial Virus Infections

What participants receive

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

  • Investigational RSV vaccine 1Biological

    Investigational RSV vaccine 1 administered intramuscularly on Day 1 and Day 30.

  • Investigational RSV vaccine 2Biological

    Investigational RSV vaccine 2 administered intramuscularly on Day 1 and Day 30.

  • Investigational RSV vaccine 3Biological

    Investigational RSV vaccine 3 administered intramuscularly on Day 1 and Day 30.

  • Investigational RSV vaccine 4Biological

    Investigational RSV vaccine 4 administered intramuscularly on Day 1 and Day 30.

  • Investigational RSV vaccine 5Biological

    Investigational RSV vaccine 5 administered intramuscularly on Day 1 and Day 30.

  • Investigational RSV vaccine 6Biological

    Investigational RSV vaccine 6 administered intramuscularly on Day 1.

  • PlaceboDrug

    Placebo administered intramuscularly on Day 1 and Day 30 and for RSV_Group F placebo administered only on Day 30.

Study groups in NCT06573281
Study groupRoleWhat they receive
RSV_Group AExperimentalNot described
Receives: Biological: Investigational RSV vaccine 1
RSV_Group BExperimentalNot described
Receives: Biological: Investigational RSV vaccine 2
RSV_Group CExperimentalNot described
Receives: Biological: Investigational RSV vaccine 3
RSV_Group DExperimentalNot described
Receives: Biological: Investigational RSV vaccine 4
RSV_Group EExperimentalNot described
Receives: Biological: Investigational RSV vaccine 5
RSV_Group FExperimentalNot described
Receives: Biological: Investigational RSV vaccine 6; Drug: Placebo
Placebo GroupPlacebo comparatorNot described
Receives: Drug: Placebo

What is being measured

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

  1. Number of participants reporting solicited administration site events within 7 days post-Dose 1

    Measured: From Day 1 to Day 7

  2. Number of participants reporting solicited administration site events within 7 days post-Dose 2

    Measured: From Day 30 to Day 36

  3. Number of participants reporting solicited systemic events within 7 days post-Dose 1

    Measured: From Day 1 to Day 7

  4. Number of participants reporting solicited systemic events within 7 days post-Dose 2

    Measured: From Day 30 to Day 36

  5. Number of participants reporting unsolicited adverse events (AEs) within 29 days post-Dose 1

    Measured: From Day 1 to Day 29

  6. Number of participants reporting unsolicited AEs within 29 days post-Dose 2

    Measured: From Day 30 to Day 58

  7. Number of participants reporting serious adverse events (SAEs)

    Measured: From Day 1 (Dose 1) up to Month 7 (6 months post-Dose 2)

  8. Number of participants reporting medically attended adverse events (MAAEs)

    Measured: From Day 1 (Dose 1) up to Month 7 (6 months post-Dose 2)

  9. Number of participants reporting adverse event of special interest (AESI)

    Measured: From Day 1 (Dose 1) up to Month 7 (6 months post-Dose 2)

  10. Number of participants reporting fatal SAEs

    Measured: From Day 1 (Dose 1) up to Month 13 (study end)

  11. Number of participants reporting related SAEs

    Measured: From Day 1 (Dose 1) up to Month 13 (study end)

  12. Number of participants reporting related AESIs

    Measured: From Day 1 (Dose 1) up to Month 13 (study end)

  13. Number of participants with clinically significant hematological and biochemical abnormalities at pre-Dose 1

    Measured: At Day 1

  14. Number of participants with clinically significant hematological and biochemical abnormalities post-Dose 1

    Measured: At Day 8

  15. Number of participants with clinically significant hematological and biochemical abnormalities post-Dose 1

    Measured: At Day 30

  16. Number of participants with clinically significant hematological and biochemical abnormalities post-Dose 2

    Measured: At Day 37

Secondary outcomes (6)

  1. RSV- A neutralizing titers expressed as Geometric mean titers (GMTs)

    Measured: At Day 1 (pre-Dose 1), Day 8 and Day 30 (post-Dose 1), Day 37, Day 59, Month 7 and Month 13 (post-Dose 2)

  2. RSV- B neutralizing titers expressed as GMTs

    Measured: At Day 1 (pre-Dose 1), Day 8 and Day 30 (post-Dose 1), Day 37, Day 59, Month 7 and Month 13 (post-Dose 2)

  3. Geometric mean fold increase in serum neutralizing titers against RSV-A from baseline

    Measured: Day 8 and Day 30 (post-Dose 1), Day 37, Day 59, Month 7 and Month 13 (post-Dose 2) compared with baseline (Day 1, pre-Dose 1)

  4. Geometric mean fold increase in serum neutralizing titers against RSV-B from baseline

    Measured: Day 8 and Day 30 (post-Dose 1), Day 37, Day 59, Month 7 and Month 13 (post-Dose 2) compared with baseline (Day 1, pre-Dose 1)

  5. Number of participants with seroresponse in terms of neutralizing titer against RSV-A

    Seroresponse is defined as at least a 4-fold increase compared to pre-dosing titer.

    Measured: Day 8 and Day 30 (post-Dose 1), Day 37, Day 59, Month 7 and Month 13 (post-Dose 2) compared with baseline (Day 1, pre-Dose 1)

  6. Number of participants with seroresponse in terms of neutralizing titer against RSV-B

    Seroresponse is defined as at least a 4-fold increase compared to pre-dosing titer.

    Measured: Day 8 and Day 30 (post-Dose 1), Day 37, Day 59, Month 7 and Month 13 (post-Dose 2) compared with baseline (Day 1, pre-Dose 1)

Timeline

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

  1. First posted27 Aug 2024
  2. Study start30 Sep 2024
  3. Primary completion26 Feb 2026
  4. Study completion26 Feb 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 1
Primary purpose
Prevention
Allocation
Randomised
Intervention model
Sequential
Masking
Quadruple blind
Who is masked
Participant, Care provider, Investigator, Outcomes assessor
Enrolment
213 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT06573281
Sponsor's protocol ID
222261
Other IDs
2024-512846-41
Status last verified
Jul 2026
First submitted
26 Aug 2024
Last updated
30 Jul 2026
Results posted
No
Data monitoring committee
Yes
FDA-regulated drug
Yes
FDA-regulated device
No
Individual data sharing
Yes: GSK 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 1 study testing Investigational RSV vaccine 1, Investigational RSV vaccine 2 and Investigational RSV vaccine 3 in people with Respiratory Syncytial Virus Infections, run by GlaxoSmithKline at 9 sites in 3 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 22 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 30 Jul 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 9 sites in United States, Spain, Australia. 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. Some participants in this study may receive a placebo. 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 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.

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?

Number of participants reporting solicited administration site events within 7 days post-Dose 1 (time frame: From Day 1 to Day 7). The study lists 16 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 NCT06573281.

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 30 Jul 2026.

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