Influenza ImmunizationPhase 1/2NCT06361875
A Study to Investigate the Safety and Immunogenicity of the Quadrivalent Influenza mRNA Vaccines in Adults Aged 18 Years and Above
A Phase 1/2 study testing Quadrivalent Influenza mRNA Vaccine MRT5421, Quadrivalent Influenza mRNA Vaccine MRT5424 and Quadrivalent Influenza mRNA Vaccine MRT5429 in people with Influenza Immunization and Healthy Volunteers, run by Sanofi Pasteur, a Sanofi Company at 13 sites in 3 countries.
Trial summary
The purpose of this study was to evaluate the safety and immunogenicity of a single intramuscular (IM) injection of different formulations of Quadrivalent Influenza Vaccine (QIV) messenger ribonucleic acid (mRNA) (MRT5421, MRT5424, and MRT5429) compared to an active control (QIV- standard dose (SD), QIV- high dose… Read more about this study
- Who is it for?
- Ages 18 years and olderHealthy volunteers can take part
- Conditions the study is for
- Influenza Immunization, Healthy Volunteers
- What is being tested?
- Quadrivalent Influenza mRNA Vaccine MRT5421, Quadrivalent Influenza mRNA Vaccine MRT5424 and Quadrivalent Influenza mRNA Vaccine MRT5429
- Type of treatment
- Vaccines, Injection or infusion
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 908 participants
- Where
- 13 sitesin 3 countries
- Study dates
- 1 Apr 2024to 9 Jun 2025
- Phase
- Phase 1/2
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
- Aged from 18 years on the day of inclusion or aged from 21 years on the days of inclusion, depending on the countries.
- A female participant was eligible to participate if she was not pregnant or breastfeeding and one of the following conditions applied:
- Was of non-childbearing potential. To be considered of non-childbearing potential, a female must of been postmenopausal for at least 1 year, or surgically sterile OR
- Was of childbearing potential and agreed to use an effective contraceptive method or abstinence from at least 4 weeks prior to study intervention administration until at least 12 weeks after study intervention administration.
- A female participant of childbearing potential must of had a negative highly sensitive pregnancy test (urine or serum as required by local regulation) within 8 hours before the 1st dose of study intervention
- Exclusion Criteria: Participants were excluded from the study if any of the following criteria applied:
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- Known or suspected congenital or acquired immunodeficiency; or receipt of immunosuppressive therapy, such as anti-cancer chemotherapy or radiation therapy, within the preceding 6 months; or long-term systemic corticosteroid therapy (prednisone or equivalent for more than 2 consecutive weeks within the past 3 months)
- Known systemic hypersensitivity to any of the study intervention components (eg, polyethylene glycol, polysorbate); history of a life-threatening reaction to the study interventions used in the study or to a product containing any of the same substances; any allergic reaction (eg, anaphylaxis) after administration of mRNA vaccine
- Previous history of myocarditis, pericarditis, and / or myopericarditis
- Known history of previous episodes of Gillian-Barre Syndrome (GBS), neuritis (including Bell's palsy), convulsions, encephalitis, transverse myelitis, and vasculitis
- Participants with an ECG that is consistent with possible myocarditis or pericarditis or, in the opinion of the investigator, demonstrates clinically relevant abnormalities that may affect participant safety or study results
- Self-reported thrombocytopenia, contraindicating Intramuscular vaccination based on Investigator's judgment
- Bleeding disorder, or receipt of anticoagulants in the 3 weeks preceding inclusion, contraindicating Intramuscular vaccination based on Investigator's judgment
- Chronic illness that, in the opinion of the Investigator, was at a stage where it might have interfered with study conduct or completion
- Moderate or severe acute illness / infection (according to Investigator's judgment) or febrile illness (temperature ≥ 38.0°C [≥ 100.4°F]) on the day of vaccination. A prospective participant was not included in the study until the condition was resolved or the febrile event subsided
- Participant who had acute infection symptoms or a positive SARS-CoV-2 RT-PCR or antigen test in the past 10 days prior to the 1st visit (V01)
- Receipt of any vaccine in the 4 weeks preceding study intervention administration or planned receipt of any vaccine in the 4 weeks following study intervention administration
- Receipt of immune globulins, blood or blood-derived products in the past 3 months
- Previous vaccination against influenza in the previous 6 months with an investigational or marketed vaccine
- Receipt of any mRNA vaccine/product in the 2 months preceding study intervention administration
- NOTE: The above information was not intended to contain all considerations relevant to a patient's potential participation in a clinical trial.
Who cannot join
None listed.
Trial locations and contacts
13 sites in 3 countries.
13 sites in 3 countries
United States11 sites
Indago Research and Health Center- Site Number : 8400032
Hialeah, Florida, 33012
Cenexel Research Centers of America- Site Number : 8400037
Hollywood, Florida, 33024
Brengle Family Medicine Site Number : 8400045
Indianapolis, Indiana, 46260
The Alliance for Multispecialty Research - KCM, LLC- Site Number : 8400034
Kansas City, Missouri, 64114
AMR Knoxville- Site Number : 8400043
Knoxville, Tennessee, 37909
AMR Lexington- Site Number : 8400042
Lexington, Kentucky, 40509
Velocity Clinical Research- New Orleans Site Number : 8400053
New Orleans, Louisiana, 70119
Velocity Clinical Research Norfolk- Site Number : 8400046
Norfolk, Nebraska, 68701
Cenexel JBR- Site Number : 8400051
Salt Lake City, Utah, 84107
Clinical Trials of Texas, Inc. - PPDS- Site Number : 8400029
San Antonio, Texas, 78229
California Research Foundation Site Number : 8400038
San Diego, California, 92123-1881
Puerto Rico1 site
Investigational Site Number : 6300002
Barrio Sabana, 00694
About this study
Official title: A Phase I/II Study to Investigate the Safety and Immunogenicity of Quadrivalent Influenza mRNA Vaccines MRT5421, MRT5424, and MRT5429 in Healthy Participants Aged 18 Years and Above
The purpose of this study was to evaluate the safety and immunogenicity of a single intramuscular (IM) injection of different formulations of Quadrivalent Influenza Vaccine (QIV) messenger ribonucleic acid (mRNA) (MRT5421, MRT5424, and MRT5429) compared to an active control (QIV- standard dose (SD), QIV- high dose (HD) [adults ≥ 65 years of age only], or quadrivalent recombinant influenza vaccine (RIV4)) in adults 18 years of age and older.
Read the detailed description
Study duration per participant was approximately 12 months.
- Treatment duration: 1 injection of one of the 7 QIV mRNA or one of the controls
- Dose escalation with sequential enrollment
- Conditions
- Influenza Immunization, Healthy Volunteers
- Being tested
- Quadrivalent Influenza mRNA Vaccine MRT5421, Quadrivalent Influenza mRNA Vaccine MRT5424, Quadrivalent Influenza mRNA Vaccine MRT5429, Quadrivalent Influenza Standard Dose Vaccine, Quadrivalent Influenza High-Dose Vaccine
- Medical subject headings
- Influenza, Human
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Quadrivalent Influenza mRNA Vaccine MRT5421Biological
Pharmaceutical form:solution in a vial-Route of administration:Intramuscular injection
Quadrivalent Influenza mRNA Vaccine MRT5424Biological
Pharmaceutical form:solution in a vial-Route of administration:Intramuscular injection
Quadrivalent Influenza mRNA Vaccine MRT5429Biological
Pharmaceutical form:solution in a vial-Route of administration:Intramuscular Injection
Quadrivalent Influenza Standard Dose VaccineBiological
Also called Fluzone Qudrivalent®
Pharmaceutical form: suspension for injection in prefilled syringe -Route of administration:Intramuscular injection
Quadrivalent Influenza High-Dose VaccineBiological
Also called Fluzone High-Dose Quadrivalent®
Pharmaceutical form:suspension for injection in pre filled syringe -Route of administration:Intramuscular injection
Quadrivalent Recombinant Influenza VaccineBiological
Also called Flublok Quadrivalent®
Pharmaceutical form:suspension for injection in pre filled syringe-Route of administration:Intramuscular injection
| Study group | Role | What they receive |
|---|---|---|
| Quadrivalent Influenza mRNA Vaccine MRT5421 Dose 1 | Experimental | participants received a single dose of QIV mRNA vaccine MRT5421 Receives: Biological: Quadrivalent Influenza mRNA Vaccine MRT5421 |
| Quadrivalent Influenza mRNA Vaccine MRT5429 Dose 1 | Experimental | participants received a single dose of QIV mRNA vaccine MRT5429 Receives: Biological: Quadrivalent Influenza mRNA Vaccine MRT5429 |
| Quadrivalent Influenza mRNA Vaccine MRT5429 Dose 2 | Experimental | participants received a single dose of QIV mRNA vaccine MRT5429 Receives: Biological: Quadrivalent Influenza mRNA Vaccine MRT5429 |
| Quadrivalent Influenza mRNA Vaccine MRT5429 Dose 3 | Experimental | participants received a single dose of QIV mRNA vaccine MRT5429 Receives: Biological: Quadrivalent Influenza mRNA Vaccine MRT5429 |
| Quadrivalent Influenza mRNA Vaccine MRT5429 Dose 4 | Experimental | participants received a single dose of QIV mRNA vaccine MRT5429 Receives: Biological: Quadrivalent Influenza mRNA Vaccine MRT5429 |
| Quadrivalent Influenza mRNA Vaccine MRT5424 Dose 1 | Experimental | participants received a single dose of QIV mRNA vaccine MRT5424 Receives: Biological: Quadrivalent Influenza mRNA Vaccine MRT5424 |
| Quadrivalent Influenza mRNA Vaccine MRT5424 Dose 2 | Experimental | participants received a single dose of QIV mRNA vaccine MRT5424 Receives: Biological: Quadrivalent Influenza mRNA Vaccine MRT5424 |
| Quadrivalent Influenza SD Vaccine | Active comparator | participants received a single dose of QIV-SD vaccine Receives: Biological: Quadrivalent Influenza Standard Dose Vaccine |
| Quadrivalent Influenza HD Vaccine | Active comparator | participants received a single dose of QIV -HD vaccine (for adults ≥ 65 years of age only) Receives: Biological: Quadrivalent Influenza High-Dose Vaccine |
| Quadrivalent Influenza RIV4 Vaccine | Active comparator | participants received a single dose of RIV4 vaccine Receives: Biological: Quadrivalent Recombinant Influenza Vaccine |
What is being measured
The primary outcome is the main question the study is designed to answer.
Number of Participants With Immediate Unsolicited Systemic Adverse Events (AEs) After Vaccine Administration
An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study vaccine, whether or not considered related to the study vaccine. An unsolicited AE is an observed AE that does not fulfill the conditions of solicited reactions, that is, pre-listed in the case report form in terms of diagnosis and onset window post-vaccination. Systemic AEs are all AEs that were not injection or administration site reactions. Immediate events are recorded to capture medically relevant unsolicited systemic AEs which occur within the first 30 minutes after vaccination.
Measured: Within 30 minutes after vaccine administration on Day 1
Number of Participants With Solicited Injection Site Reactions After Vaccine Administration
An adverse reaction (AR) is any noxious and unintended response to a study vaccine related to any dose. Solicited injection site reactions are reactions at and around the injection site of the vaccine observed and reported under the conditions (nature and onset) pre-listed in the protocol and case report form.
Measured: Within 7 days after vaccine administration on Day 1
Number of Participants With Solicited Systemic Reactions After Vaccine Administration
An AR is any noxious and unintended response to a study vaccine related to any dose. Solicited systemic reactions are systemic AEs observed and reported under the conditions (nature and onset) pre-listed in the protocol and case report form.
Measured: Within 7 days after vaccine administration on Day 1
Number of Participants With Unsolicited Adverse Events After Vaccine Administration
An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study vaccine, whether or not considered related to the study vaccine. An unsolicited AE is an observed AE that does not fulfill the conditions of solicited reactions, that is, pre-listed in the case report form in terms of diagnosis and onset window post-vaccination.
Measured: Within 28 days after vaccine administration on Day 1
Number of Participants With Medically Attended Adverse Events (MAAEs)
An MAAE is a new onset or a worsening of a condition that prompts the participant or participant's parent/legally acceptable representative to seek unplanned medical advice at a physician's office or emergency department.
Measured: Within 180 days after vaccine administration on Day 1
Number of Participants With Serious Adverse Events (SAEs) and Adverse Event of Special Interest (AESIs)
An SAE is any untoward medical occurrence that at any dose results in death or is life-threatening or requires inpatient hospitalization or prolongation of existing hospitalization or results in persistent or significant disability/incapacity or is a congenital anomaly/birth defect or is an important medical event. An AESI (serious or non-serious) is 1 of scientific and medical concern specific to the Sponsor's study vaccine or program, for which ongoing monitoring and rapid communication by the investigator to the Sponsor can be appropriate. The AESIs was defined as anaphylactic reactions (including bronchospasms, and laryngeal spasms), Guillain-Barré syndrome, neuritis (including Bell's palsy), myocarditis, pericarditis, myopericarditis and vasculitis.
Measured: From the vaccine administration (Day 1) until 12 months after vaccine administration, approximately 366 days
Number of Participants With Abnormal Biological Test Results
Blood samples were collected for the assessment of abnormal hematology and clinical chemistry parameters. Only participants with outside the normal range hematology and clinical chemistry parameters are reported.
Measured: Within 8 days after vaccine administration on Day 1
Geometric Mean of Hemagglutination Inhibition (HAI) Antibody (Ab) Titer at Day 1
The HAI Ab was measured by hemagglutinin inhibition using quality control sera (sheep, ferret and/or human sera) measurement method. The 95% confidence interval (CI) was based on the Clopper-Pearson method.
Measured: Day 1
Geometric Mean of Hemagglutination Inhibition Antibody Titer at Day 29
The HAI Ab was measured by hemagglutinin inhibition using quality control sera (sheep, ferret and/or human sera) measurement method. The 95% CI was based on the Clopper-Pearson method.
Measured: Day 29
Percentage of Participants With Detectable Hemagglutination Inhibition Antibody Titer >=1:10 at Day 1
The HAI Ab was measured by hemagglutinin inhibition using quality control sera (sheep, ferret and/or human sera) measurement method. The 95% CI for the single percentage was based on the Clopper-Pearson method. The percentages are rounded off to the tenth decimal place.
Measured: Day 1
Percentage of Participants With Detectable Hemagglutination Inhibition Antibody Titer >=1:10 at Day 29
The HAI Ab was measured by hemagglutinin inhibition using quality control sera (sheep, ferret and/or human sera) measurement method. The 95% CI for the single percentage was based on the Clopper-Pearson method. The percentages are rounded off to the tenth decimal place.
Measured: Day 29
Geometric Mean Ratio of Hemagglutination Inhibition Antibody Titer at Day 29
The HAI Ab was measured by hemagglutinin inhibition using quality control sera (sheep, ferret and/or human sera) measurement method. The geometric mean ratio of antibody titer at post-vaccination over pre-vaccination is reported. The 95% CI was based on the Clopper-Pearson method.
Measured: Days 1 and 29
Percentage of Participants With Seroconversion of Hemagglutination Inhibition Antibody Titer at Day 29
The seroconversion was defined as titer <10 on Day 1 and post-injection titer >=40 on Day 29; or defined as titer >=10 on Day 1 and a >=4-fold increase in titer on Day 29. The 95% CI for the single percentage was based on the Clopper-Pearson method. The percentages are rounded off to the tenth decimal place.
Measured: Day 29
Percentage of Participants With Hemagglutination Inhibition Antibody Titer >=1:40 at Day 29
The HAI Ab was measured by hemagglutinin inhibition using quality control sera (sheep, ferret and/or human sera) measurement method. The 95% CI for the single percentage was based on the Clopper-Pearson method. The percentages are rounded off to the tenth decimal place.
Measured: Day 29
Percentage of Participants With >=2 and >=4 Fold Increase in Hemagglutination Inhibition Antibody Titer at Day 29
The HAI Ab was measured by hemagglutinin inhibition using quality control sera (sheep, ferret and/or human sera) measurement method. The 95% CI for the single percentage was based on the Clopper-Pearson method. The percentages are rounded off to the tenth decimal place.
Measured: Days 1 and 29
Secondary outcomes (3)
Geometric Mean of Neutralization Test (NT) Antibody Titer at Days 1 and 29
The NT Ab was planned to be measured using seroneutralization (SN) measurement method. The 95% CI was planned to be calculated using the Clopper-Pearson method.
Measured: Days 1 and 29
Geometric Mean Ratio of Neutralization Test Antibody Titer at Day 29
The NT Ab was planned to be measured using SN measurement method. The geometric mean ratio of antibody titer at post-vaccination over pre-vaccination was planned to be reported. The 95% CI was planned to be calculated using the Clopper-Pearson method.
Measured: Days 1 and 29
Percentage of Participants With >=2 and >=4 Fold Increase in Neutralization Test Antibody Titer at Day 29
The NT Ab was planned to be measured using SN measurement method. The 95% CI for the single percentage was planned to be calculated using the Clopper-Pearson method.
Measured: Days 1 and 29
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted12 Apr 2024
- Study start1 Apr 2024
- Primary completion9 Jun 2025
- Study completion9 Jun 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Other trials for Influenza ImmunizationStudies of the same condition, open and under way.
- More trials run by Sanofi Pasteur, a Sanofi CompanyThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
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 1/2
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- Parallel with dose escalation for sentinel cohort
- Masking
- Triple blind
- Who is masked
- Participant, Investigator, Outcomes assessor
- Enrolment
- 908 participants (actual)
Sponsor and investigators
- Lead sponsor
- Sanofi Pasteur, a Sanofi Company
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06361875
- Sponsor's protocol ID
- VAV00045
- Other IDs
- U1111-1295-2852
- Status last verified
- Jul 2026
- First submitted
- 4 Apr 2024
- Last updated
- 4 Aug 2026
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- Yes: Qualified researchers may request access to patient level data and related study documents including the clinical study report, study protocol with any amendments, blank case report form, statistical analysis plan, and dataset specifications. Patient level data will be anonymized and study documents will be redacted to protect the privacy of trial participants. Further details on Sanofi's data sharing criteria, eligible studies, and process for requesting access can be found at: https://vivli.org