Safety and Immunogenicity of Quadrivalent Influenza mRNA Vaccine MRT5410 in Adult Participants 18 Years of Age and Older

Study Overview
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Brief Summary
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The purpose of this study is to evaluate the safety and immunogenicity of a single intramuscular (IM) injection of up to 3 dose levels of Quadrivalent Influenza mRNA Vaccine MRT5410 compared to an active control (QIV SD, QIV HD [adults ≥ 65 years of age only], or RIV4) in adults 18 years of age and older.

Detailed Description
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Approximately 12 months

Official Title
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Safety and Immunogenicity of Quadrivalent Influenza mRNA Vaccine MRT5410 in Adults Aged 18 Years and Older

Conditions
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Influenza Immunization

Intervention / Treatment
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* Biological: Quadrivalent Influenza mRNA Vaccine MRT5410
* Biological: Quadrivalent Recombinant Influenza vaccine RIV4
* Biological: Quadrivalent Inactivated Influenza Standard Dose QIV-SD
* Biological: Quadrivalent Inactivated Influenza High Dose QIV-HD


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Aged 18 years on the day of inclusion (US) and aged 21 years on the day of inclusion (Puerto Rico) 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 study intervention administration until at least 12 weeks after study intervention administration. 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) Previous history of myocarditis, pericarditis, and / or myopericarditis Self-reported thrombocytopenia, contraindicating IM vaccination based on Investigator's judgment Bleeding disorder, or receipt of anticoagulants in the 3 weeks preceding inclusion, contraindicating IM vaccination based on Investigator's judgment 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 should not be included in the study until the condition has resolved or the febrile event has subsided Self-reported or documented seropositivity for human immunodeficiency virus, hepatitis B virus, or hepatitis C virus NOTE: The above information is not intended to contain all considerations relevant to a patient's potential participation in a clinical trial.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: Sentinel Cohort: Open label Main Cohort: Open label (Sponsor, except laboratory testing personnel) Blinded (Sites, except for those preparing/administering study intervention)
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Group 1: Quadrivalent Influenza mRNA Vaccine MRT5410 low dose<br>participants will receive a single dose (low) of QIV mRNA vaccine | Biological: Quadrivalent Influenza mRNA Vaccine MRT5410<br>* Pharmaceutical form: Liquid frozen solution for injection in a vial Route of administration: Intramuscular<br>|
| Experimental: Group 2: Quadrivalent Influenza mRNA Vaccine MRT5410 medium dose<br>participants will receive a single dose (medium) of QIV mRNA vaccine | Biological: Quadrivalent Influenza mRNA Vaccine MRT5410<br>* Pharmaceutical form: Liquid frozen solution for injection in a vial Route of administration: Intramuscular<br>|
| Experimental: Group 3: Quadrivalent Influenza mRNA Vaccine MRT5410 high dose<br>participants will receive a single dose (high) of QIV mRNA vaccine | Biological: Quadrivalent Influenza mRNA Vaccine MRT5410<br>* Pharmaceutical form: Liquid frozen solution for injection in a vial Route of administration: Intramuscular<br>|
| Active Comparator: Group 4: RIV4<br>participants will receive a single dose of RIV4 vaccine | Biological: Quadrivalent Recombinant Influenza vaccine RIV4<br>* Pharmaceutical form: Liquid suspension for injection in prefilled syringe Route of administration: Intramuscular<br>* Other names: Flublok Quadrivalent®;|
| Active Comparator: Group 5: QIV-SD<br>participants will receive a single dose of QIV-SD vaccine | Biological: Quadrivalent Inactivated Influenza Standard Dose QIV-SD<br>* Pharmaceutical form: Liquid suspension for injection in prefilled syringe Route of administration: Intramuscular<br>* Other names: Fluzone Quadrivalent®;|
| Active Comparator: Group 6: QIV-HD<br>participants will receive a single dose of QIV -HD vaccine | Biological: Quadrivalent Inactivated Influenza High Dose QIV-HD<br>* Pharmaceutical form: Liquid suspension for injection in prefilled syringe Route of administration: Intramuscular<br>* Other names: Fluzone High-Dose Quadrivalent®;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of participants with immediate adverse events (AEs) | Unsolicited systemic AEs that occur within 30 minutes after vaccination | Within 30 minutes after injection | 
| Number of participants with solicited injection site reactions or systemic reactions | Adverse reactions pre-listed in the protocol and case report form (CRF) Injection site reactions: pain, redness, swelling, hardening, bruising Systemic reactions: fever, headache, malaise, myalgia, arthralgia, chills | Within 7 days after injection | 
| Number of participants with unsolicited AEs | AEs that do not fulfill the conditions of solicited reactions | Within 28 days after injection | 
| Number of participants with medically attended adverse events (MAAE)s | AEs with a new onset or a worsening of a condition that prompts the participant or participant to seek unplanned medical advice at a physician's office or Emergency Department | Within 180 days after injection | 
| Number of participants with serious adverse events (SAEs) | SAEs reported throughout the study | From Day 1 until Day 366 | 
| Number of participants with out-of-range biological test results | Out-of-range biological test results (including shift from baseline values) | Within 8 days after injection | 
| Individual Hemagglutination inhibition (HAI) titer | Antibody titers are expressed as GMTs at baseline and post-baseline | Day 1 and Day 29 | 
| Percentage of participants with detectable antibody HAI titers greater than or equal to (≥) 10 [1/dil] |  | Day 1 and Day 29 | 
| Individual HAI titer ratio | Ratios of antibody titers measured by HAI in each group before and after vaccination | Day 1 and Day 29 | 
| Number of participants archiving HAI seroconversion against Antigens | Number of participants with titer < 10 [1/dil] at Day 1 and post-vaccination titer ≥ 40 [1/dil] at Day 29, or titer ≥ 10 [1/dil] at Day 1 and a ≥ 4-fold-rise in titer [1/dil] at Day 29 | Day 1 and Day 29 | 
| Percentage of participants with antibody HAI titers greater than or equal to (≥) 40 [1/dil] |  | Day 29 | 
| Percentage of participants with 2-fold and 4-fold rise in HAI titers |  | Day 1 and Day 29 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Neutralizing Ab titers | Neutralizing Ab titers expressed as GMTs | Day 1 and Day 29 | 
| Individual neutralizing antibodies titer ratio |  | Day 1 and Day 29 | 
| Percentage of participants with 2-fold and 4-fold increase in neutralizing titers |  | Day 1 and Day 29 | 
| Individual HAI Ab titer ratio |  | Day 1, Day 91, Day 181 and Day 366 | 
| Percentage of participants with antibody HAI titers greater than or equal to (≥) 40 [1/dil] |  | Day 91, Day 181 and Day 366 | 
| Individual antibodies HAI titer ratio |  | Day 1, Day 91, Day 181 and Day 366 |