Study to Evaluate Safety and Immunogenicity of a Pandemic Flu H5 mRNA Vaccine in Healthy Adults Aged 18 Years and Older

NCT ID: NCT06727058

Last Updated: 2026-01-21

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

ACTIVE_NOT_RECRUITING

Clinical Phase

PHASE1/PHASE2

Total Enrollment

276 participants

Study Classification

INTERVENTIONAL

Study Start Date

2024-12-09

Study Completion Date

2026-03-31

Brief Summary

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The purpose of this study is to evaluate a pandemic flu H5 strain messenger ribonucleic acid (mRNA) vaccine at 3 dose levels (low, medium, and high) in comparison with placebo in 276 healthy adult participants to select the adequate dose for further clinical development.

The duration per participant will be approximately 13 months.

Detailed Description

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Conditions

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Influenza Immunization

Study Design

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Allocation Method

RANDOMIZED

Intervention Model

SEQUENTIAL

Primary Study Purpose

PREVENTION

Blinding Strategy

TRIPLE

Participants Investigators Outcome Assessors
Modified double blind (participants; sites, except for those preparing/administering study intervention; and Sponsor will be blinded). Sponsor's internal safety monitoring team will be unblinded if necessary. "Evaluation of the Safety of the sentinel cohorts will be unmasked for the Sponsor's safety Team".

Study Groups

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Group 1: Low Dose Pandemic flu H5 mRNA vaccine

Participants will receive 2 injections of pandemic flu H5 mRNA vaccine 21 days apart (at Day 01 and Day 22)

Group Type EXPERIMENTAL

Pandemic flu H5 mRNA vaccine

Intervention Type BIOLOGICAL

Pharmaceutical Form: Suspension for injection

Route of Administration: Intramuscular (IM)

Group 2: Medium Dose Pandemic flu H5 mRNA vaccine

Participants will receive 2 injections of pandemic flu H5 mRNA vaccine 21 days apart (at Day 01 and Day 22)

Group Type EXPERIMENTAL

Pandemic flu H5 mRNA vaccine

Intervention Type BIOLOGICAL

Pharmaceutical Form: Suspension for injection

Route of Administration: Intramuscular (IM)

Group 3: High Dose Pandemic flu H5 mRNA vaccine

Participants will receive 2 injections of pandemic flu H5 mRNA vaccine 21 days apart (at Day 01 and Day 22)

Group Type EXPERIMENTAL

Pandemic flu H5 mRNA vaccine

Intervention Type BIOLOGICAL

Pharmaceutical Form: Suspension for injection

Route of Administration: Intramuscular (IM)

Group 4: Placebo

Participants will receive 2 injections of placebo 21 days apart (at Day 01 and Day 22)

Group Type PLACEBO_COMPARATOR

Placebo

Intervention Type OTHER

Pharmaceutical Form: Liquid solution for injection

Route of Administration: Intramuscular (IM)

Interventions

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Pandemic flu H5 mRNA vaccine

Pharmaceutical Form: Suspension for injection

Route of Administration: Intramuscular (IM)

Intervention Type BIOLOGICAL

Placebo

Pharmaceutical Form: Liquid solution for injection

Route of Administration: Intramuscular (IM)

Intervention Type OTHER

Eligibility Criteria

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Inclusion Criteria

* Aged 18 years or older on the day of inclusion.
* A female participant is eligible to participate if she is not pregnant or breastfeeding and one of the following conditions applies:

* Is of non-childbearing potential. To be considered of non-childbearing potential, a female must be postmenopausal for at least 1 year, or surgically sterile.

OR

• Is of childbearing potential and agrees to use an effective contraceptive method or abstinence from at least 4 weeks prior to each study intervention administration until at least 12 weeks after the last study intervention administration.

* A female participant of childbearing potential must have a negative highly sensitive pregnancy test (urine or serum as required by local regulation) within 8 hours before the first dose of study intervention.

Exclusion Criteria

* 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 an mRNA vaccine .
* Previous history of myocarditis, pericarditis, and/or myopericarditis.
* Known history of previous episodes of Guillain-Barré Syndrome (GBS), neuritis (including Bell's palsy), convulsions , encephalitis, transverse myelitis, and vasculitis.
* Participants with an electrocardiogram 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 IM injection based on investigator's judgment.
* Bleeding disorder, or receipt of anticoagulants in the 3 weeks preceding inclusion, contraindicating IM injection based on investigator's judgment.
* Chronic illness that, in the opinion of the investigator, is at a stage where it might interfere 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 study intervention. A prospective participant should not be included in the study until the condition has resolved or the febrile event has subsided.
* Alcohol, prescription drug, or substance abuse that, in the opinion of the investigator, might interfere with the study conduct or completion.
* Participant who had acute infectious symptoms or a positive severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) reverse transcriptase polymerase chain reaction (RT PCR) or antigen test in the past 10 days prior to the first visit (V)01.
* Receipt of any vaccine other than an mRNA vaccine in the 4 weeks preceding study intervention administration or planned receipt of any vaccine other than an mRNA vaccine in the 3 weeks following the second dose of the study intervention .
* Receipt of immune globulins, blood or blood-derived products in the past 3 months.
* Receipt of any mRNA vaccine/product in the 2 months preceding study intervention administration or planned receipt of any mRNA vaccine in the 2 months after the second dose of the study intervention.
* Participation at the time of study enrollment (or in the 4 weeks preceding study intervention administration) or planned participation during the present study period in another clinical study investigating a vaccine, drug, medical device, or medical procedure.
* Previous history of participation in an H5 influenza A vaccine study. This includes any influenza subtypes that contain H5 such as H5N1, H5N8, or H5N6.

Note: The above information is not intended to contain all considerations relevant to a potential participation in a clinical trial.
Minimum Eligible Age

18 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

Yes

Sponsors

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Sanofi Pasteur, a Sanofi Company

INDUSTRY

Sponsor Role lead

Responsible Party

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Responsibility Role SPONSOR

Locations

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Velocity Clinical Research - San Diego- Site Number : 8400013

La Mesa, California, United States

Site Status

Accel Research Sites Network - DeLand Clinical Research Unit- Site Number : 8400002

DeLand, Florida, United States

Site Status

ARSN-Lakeland CRU- Site Number : 8400006

Lakeland, Florida, United States

Site Status

Accel Research Sites - St. Petersburg- Site Number : 8400004

Largo, Florida, United States

Site Status

Atlanta Clinical Research Center- Site Number : 8400007

Atlanta, Georgia, United States

Site Status

Accel Research Site - NeuroStudies.net, LLC - ERN - PPDS- Site Number : 8400003

Decatur, Georgia, United States

Site Status

QUEST Research Institute- Site Number : 8400014

Bingham Farms, Michigan, United States

Site Status

Velocity Clinical Research - Norfolk- Site Number : 8400015

Norfolk, Nebraska, United States

Site Status

Velocity Clinical Research - Omaha- Site Number : 8400012

Omaha, Nebraska, United States

Site Status

Velocity Clinical Research - Springdale- Site Number : 8400010

Cincinnati, Ohio, United States

Site Status

Coastal Carolina Research Center - North Charleston- Site Number : 8400001

North Charleston, South Carolina, United States

Site Status

Olympus Clinical Research - Sugar Land- Site Number : 8400009

Sugar Land, Texas, United States

Site Status

Velocity Clinical Research, Salt Lake City- Site Number : 8400011

West Jordan, Utah, United States

Site Status

Charlottesville Medical Research- Site Number : 8400005

Charlottesville, Virginia, United States

Site Status

Countries

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United States

Related Links

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Other Identifiers

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VBS00001

Identifier Type: -

Identifier Source: org_study_id

U1111-1309-8833

Identifier Type: OTHER

Identifier Source: secondary_id

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