Study of Different Formulations of Vaccines Encoding the RSV Monovalent Antigen or the Flu H5 Antigen in Participants 18 to 49 Years of Age

NCT07516418 | Recruiting Phase 1

• 2 other identifiers: VAV00053U1111-1322-6386
• Study Type: interventional
• Target: 570
• Locations: 1 country
• Sites: 6

Brief Summary

The purpose of this study is to evaluate the safety and immunogenicity of different formulations of vaccines encoding the RSV monovalent antigen or the Flu hemagglutinin subtype 5 (H5) antigen in healthy participants aged 18 to 49 years. The total duration of study participation for each participant varies by stage and treatment arm. Stage 1:

• For Arm 1, Arm 2, and Arm 3 the duration of study participation will be approximately 7 months for each participant.
• For Arm 4, Arm 5, and Arm 6 the duration of study participation will be approximately 6 months for each participant. Stage 2: For all arms, the duration of study participation will be approximately 7 months for each participant.

Conditions

Respiratory Syncytial Virus (RSV); Influenza A(H5N1)

Keywords

RSV; RSV Infection; RSV Vaccine; Flu; Flu Infection; Flu Vaccine

Outcome Measures

Primary Outcomes (14)

• Presence of any unsolicited systemic Adverse Events (AEs) reported within 30 minutes after vaccination

  On Day 1

• Presence of solicited injection site reactions (ie, injection site pain, injection site erythema, injection site swelling, pre-listed in participant's diary and in the eCRF (electronic case report form)) occurring through 7 days after each vaccination

  Day 1 through day 8

• Presence of solicited systemic reactions (ie, fever, headache, and only new or worsened fatigue, myalgia, arthralgia, and chills pre-listed in the participant's diary and in the eCRF) occurring through 7 days after each vaccination

  Day 1 through day 8

• Presence of unsolicited AEs reported through 20 days after the first vaccination and after the second vaccination for IMPs with the Flu H5 antigen

  Day 1 through day 21

• Presence of unsolicited AEs reported through 28 days after vaccination for IMPs with the RSV antigen

  Day 1 through day 29

• Presence of SAEs (Serious Adverse Events) and AESIs (Adverse Events of Special Interest) throughout the study (ie, through 6 months after vaccination)

  SAE: Screening day through day 202 (IMPs containing Flu H5 antigen), Screening day through day 181 (IMPs containing RSV antigen); AESI: Day 1 through day 202 (IMPs containing Flu H5 antigen), Day 1 through day 181 (IMPs containing RSV antigen)

• Presence of out-of-range biological test results (including shift from baseline values) through 7 days after each vaccination

  Screening through day 8

• Presence of AEs leading to study discontinuation throughout the study (ie, through 6 months after vaccination)

  Screening through day 202 (IMPs containing Flu H5 antigen), Screening through day 181 (IMPs containing RSV antigen)

• RSV A and RSV B serum nAb (neutralizing antibodies) titers at pre-vaccination and 28 days post-vaccination in all participants receiving IMPs with the RSV antigen

  Day 1 and day 29

• Flu H5 antibody (Ab) titer measured by hemagglutination inhibition (HAI) at pre-vaccination and 21 and 42 days post-vaccination in all participants receiving IMPs with the Flu H5 antigen

  Day 1, day 22 and day 43

• Hemagglutination Inhibition (HAI) geometric mean titer ratio at 21 and 42 days post-vaccination relative to pre-vaccination for all participants receiving IMPs with the Flu H5 antigen

  Ratio of post-vaccination to pre-vaccination hemagglutination inhibition (HAI) antibody titers, calculated as Day 22/Day 1 and Day 43/Day 1.

  Day 1, day 22 and day 43

• Seroconversion rate based on Hemagglutination inhibition (HAI) antibody titers at pre-vaccination and 21 and 42 days post-vaccination in all participants receiving IMPs with the Flu H5 antigen

  Day 1, day 22 and day 43

• Proportion of participants with Hemagglutination Inhibition (HAI) antibody titer ≥40 at pre-vaccination and 21 and 42 days post-vaccination in all participants receiving IMPs with the Flu H5 antigen

  Day 1, day 22, and day 43

• Proportion of participants with detectable HAI antibody titer ≥10 at pre-vaccination and 21 and 42 days post-vaccination in all participants receiving IMPs with the Flu H5 antigen

  Day 1, day 22, and day 43

Secondary Outcomes (5)

• Geometric mean neutralizing antibody titers measured by Neutralization Assay (NT) at pre-vaccination and 21 and 42 days post-vaccination in all participants receiving IMPs with the Flu H5 antigen

  Day 1, day 22, and day 43

• Neutralizing antibody titer ratio at pre-vaccination and 21 and 42 days post-vaccination in all participants receiving IMPs with the Flu H5 antigen

  Day 1, day 22, and day 43

• Proportion of participants with neutralizing antibody titers ≥20, ≥40, and ≥80 at pre-vaccination and 21 and 42 days post-vaccination in all participants receiving IMPs with the Flu H5 antigen

  Day 1, day 22, and day 43

• Proportion of participants with detectable neutralizing antibody titers ≥10 at pre-vaccination and 21 and 42 days post-vaccination in all participants receiving IMPs with the Flu H5 antigen

  Day 1, day 22, and day 43

• Proportion of participants with ≥2-fold and ≥4-fold increase in neutralizing antibody titers at pre-vaccination and 21 and 42 days post-vaccination in all participants receiving IMPs with the Flu H5 antigen

  Day 1, day 22, and day 43

Study Arms (12)

Stage 1, Arm 1

EXPERIMENTAL

Participants will receive a single IM (Intramuscular) injection on day 1 and day 22 of the H5 Flu vaccines according to their randomization schedule.

Biological: H5 Flu Investigational Medical Product (IMP) 1

Stage 1, Arm 2

EXPERIMENTAL

Participants will receive a single IM (Intramuscular) injection on day 1 and day 22 of the H5 Flu vaccines according to their randomization schedule.

Biological: H5 Flu IMP 2

Stage 1, Arm 3

EXPERIMENTAL

Participants will receive a single IM (Intramuscular) injection on day 1 and day 22 of the H5 Flu vaccines according to their randomization schedule.

Biological: H5 Flu IMP 3

Stage 1, Arm 4

EXPERIMENTAL

Participants will receive a single IM (Intramuscular) injection on day 1 of the RSV vaccines according to their randomization schedule.

Biological: RSV IMP 4

Stage 1, Arm 5

EXPERIMENTAL

Participants will receive a single IM (Intramuscular) injection on day 1 of the RSV vaccines according to their randomization schedule.

Biological: RSV IMP 5

Stage 1, Arm 6

EXPERIMENTAL

Participants will receive a single IM (Intramuscular) injection on day 1 of the RSV vaccines according to their randomization schedule.

Biological: RSV IMP 6

Stage 2, Arm 1

EXPERIMENTAL

Participants will receive a single IM (Intramuscular) injection on day 1 and day 22 of the H5 Flu vaccines according to their randomization schedule.

Biological: H5 Flu IMP 7

Stage 2, Arm 2

EXPERIMENTAL

Participants will receive a single IM (Intramuscular) injection on day 1 and day 22 of the H5 Flu vaccines according to their randomization schedule.

Biological: H5 Flu IMP 8

Stage 2, Arm 3

EXPERIMENTAL

Participants will receive a single IM (Intramuscular) injection on day 1 and day 22 of the H5 Flu vaccines according to their randomization schedule.

Biological: H5 Flu IMP 9

Stage 2, Arm 4

EXPERIMENTAL

Participants will receive a single IM (Intramuscular) injection on day 1 and day 22 of the H5 Flu vaccines according to their randomization schedule.

Biological: H5 Flu IMP 10

Stage 2, Arm 5

EXPERIMENTAL

Participants will receive a single IM (Intramuscular) injection on day 1 and day 22 of the H5 Flu vaccines according to their randomization schedule.

Biological: H5 Flu IMP 11

Stage 2, Arm 6

EXPERIMENTAL

Participants will receive a single IM (Intramuscular) injection on day 1 and day 22 of the H5 Flu vaccines according to their randomization schedule.

Biological: H5 Flu IMP 12

Interventions

H5 Flu IMP 2 BIOLOGICAL

Suspension for injection. Route of administration: Intramuscular (IM) injection

Stage 1, Arm 2

H5 Flu IMP 3 BIOLOGICAL

Suspension for injection. Route of administration: Intramuscular (IM) injection

Stage 1, Arm 3

RSV IMP 4 BIOLOGICAL

Suspension for injection. Route of administration: Intramuscular (IM) injection

Stage 1, Arm 4

RSV IMP 5 BIOLOGICAL

Suspension for injection. Route of administration: Intramuscular (IM) injection

Stage 1, Arm 5

RSV IMP 6 BIOLOGICAL

Suspension for injection. Route of administration: Intramuscular (IM) injection

Stage 1, Arm 6

H5 Flu IMP 8 BIOLOGICAL

Suspension for injection. Route of administration: Intramuscular (IM) injection

Stage 2, Arm 2

H5 Flu IMP 9 BIOLOGICAL

Suspension for injection. Route of administration: Intramuscular (IM) injection

Stage 2, Arm 3

H5 Flu IMP 10 BIOLOGICAL

Suspension for injection. Route of administration: Intramuscular (IM) injection

Stage 2, Arm 4

H5 Flu IMP 11 BIOLOGICAL

Suspension for injection. Route of administration: Intramuscular (IM) injection

Stage 2, Arm 5

H5 Flu IMP 12 BIOLOGICAL

Suspension for injection. Route of administration: Intramuscular (IM) injection

Stage 2, Arm 6

H5 Flu Investigational Medical Product (IMP) 1 BIOLOGICAL

Suspension for injection. Route of administration: Intramuscular (IM) injection

Stage 1, Arm 1

H5 Flu IMP 7 BIOLOGICAL

Suspension for injection. Route of administration: Intramuscular (IM) injection

Stage 2, Arm 1

Eligibility Criteria

• Age: 18 Years - 49 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• A female participant is eligible to participate if she is not pregnant or breastfeeding and of the following conditions applies:
• Is of NCBP (Non-Child-Bearing Potential). To be considered of NCBP, a female must be post-menopausal for at least 1 year, or surgically sterile. OR
• Is of CBP (Child-Bearing Potential) and uses an effective contraceptive method or abstinence from at least 4 weeks prior to study intervention administration until at least 12 weeks after the last study intervention administration.

You may not qualify if:

• Any condition which, in the opinion of the Investigator, might interfere with the evaluation of the study objectives
• The above information is not intended to contain all considerations relevant to a patient's potential participation in a clinical trial.

Sponsors & Collaborators

• Sanofi: lead

Study Sites (6)

Site # 0361002

Griffith, Queensland, 4222, Australia

RECRUITING

Site # 0361001

Herston, Queensland, 4006, Australia

RECRUITING

Site # 0361003

Morayfield, Queensland, 4506, Australia

RECRUITING

Site # 0361005

Sippy Downs, Queensland, 4556, Australia

RECRUITING

Site # 03610004

South Brisbane, Queensland, 4104, Australia

RECRUITING

Site # 036006

Taringa, Queensland, 4068, Australia

RECRUITING

MeSH Terms

Conditions

Respiratory Syncytial Virus Infections; Influenza, Human

Interventions

Inosine Monophosphate

Condition Hierarchy (Ancestors)

Pneumovirus Infections; Paramyxoviridae Infections; Mononegavirales Infections; RNA Virus Infections; Virus Diseases; Infections; Respiratory Tract Infections; Orthomyxoviridae Infections; Respiratory Tract Diseases

Intervention Hierarchy (Ancestors)

Inosine Nucleotides; Purine Nucleotides; Purines; Heterocyclic Compounds, 2-Ring; Heterocyclic Compounds, Fused-Ring; Heterocyclic Compounds; Nucleotides; Nucleic Acids, Nucleotides, and Nucleosides; Ribonucleotides

Central Study Contacts

Sanofi Trial Transparency Email Recommended (Toll free for US and Canada)

CONTACT

800-633-1610; contact-us@sanofi.com

Study Design

• Study Type: interventional
• Phase: phase 1
• Allocation: RANDOMIZED
• Masking: TRIPLE
• Who Masked: PARTICIPANT, CARE PROVIDER, INVESTIGATOR
• Masking Details: Modified double-blind design for Sentinel and Main Cohorts. * Blinded to formulation: Participants; Investigators; Sponsor study staff (except biostatistician); Sponsor laboratory personnel (during interim analysis); Sponsor SMT for Main Cohorts only * Unblinded to formulation: Staff preparing and administering study vaccines (at group level); Study biostatistician (throughout study); Sponsor SMT for Sentinel Cohorts, including ESDRs; SMT may receive unblinded data in case of identified safety concern evaluate the potential safety signal. * Blinded to antigen assignment (RSV vs. Flu H5): None * Unblinded to antigen assignment (RSV vs. Flu H5): Investigators; Participants; Sponsor study staff; Sponsor laboratory personnel (for immunogenicity assays); Study biostatistician; SMT
• Purpose: PREVENTION
• Intervention Model: SEQUENTIAL
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: March 31, 2026
• First Posted: April 8, 2026
• Study Start: April 15, 2026
• Primary Completion (Estimated): April 4, 2027
• Study Completion (Estimated): April 4, 2027
• Last Updated: May 8, 2026

Record last verified: 2026-05

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, SAP

Locations

AU (6)