Study of a Combination Vaccine Comprised of Different Recombinant Spike Antigen Levels of a Matrix-M Adjuvanted Recombinant COVID-19 Vaccine and High-Dose Inactivated Influenza Vaccine in Adult Participants 50 Years of Age and Older

A Phase 1/2, Parallel, Randomized, Modified Double-blind, Multi-arm Study to Assess the Safety and Immunogenicity of a Combination Vaccine Comprised of Different Recombinant Spike Antigen Levels of a Matrix-M Adjuvanted Recombinant COVID-19 Vaccine and High-dose Inactivated Influenza Vaccine in Adult Participants 50 Years of Age and Older

Study VBT00001 is planned to be a Phase 1/2, randomized, modified double-blind, active-controlled, multi-center study to be conducted in approximately 980 adults aged 50 years and older in the United States.

The purpose of the study is to assess the safety and immunogenicity of IIV-HD (high-dose inactivated influenza vaccine) + rC19 (adjuvanted recombinant COVID-19 vaccine) vaccine comprised of IIV-HD combined with different recombinant Spike (rS) antigen levels of rC19 compared to IIV-HD alone, rC19 (dose 1) alone, and IIV-HD and rC19 (dose 1) (coadministered in opposite arms).

Placebo will be coadministered in the IIV-HD alone, rC19 (dose 1) alone, and IIV-HD + rC19 study groups to control for the number of injections and to maintain observer-blinding.

Thus, each participant will receive two injections at enrollment, one in each deltoid muscle.

Study details include:

• The study duration will be approximately 12 months
• Study intervention will be administered via a single intramuscular (IM) injection into the right and left deltoid muscles on D01
• Dose escalation with sequential enrollment (sentinel cohort followed by main cohort for a given dose)
• The visit frequency will be D01, D09 (telephone call), D30, D182 (telephone call), and D366 (telephone call)

Number of Participants:

Approximately 980 participants are expected to be randomized.

Study Overview

• Status: Completed
• Conditions: Influenza Immunization; COVID-19 Immunization
• Intervention / Treatment: Other: Placebo (0.9% NaCl); Biological: rC19 (dose 1); Biological: IIV-HD; Biological: IIV-HD + rC19 (dose 1); Biological: IIV-HD + rC19 (dose 2); Biological: IIV-HD + rC19 (dose 3); Biological: IIV-HD + rC19 (dose 4)

• Study Type: Interventional
• Enrollment (Actual): 980
• Phase: Phase 2; Phase 1

Contacts and Locations

Study Locations

• United States
  • Alabama
    • Birmingham, Alabama, United States, 35211
      • Simon Williamson Clinic - Birmingham- Site Number : 8400003
    • Huntsville, Alabama, United States, 35802-2568
      • AES - DRS - Optimal Research Alabama - Huntsville Site Number : 8400006
  • Arizona
    • Tucson, Arizona, United States, 85741
      • Orange Grove Family Practice- Site Number : 8400012
  • Florida
    • The Villages, Florida, United States, 32162
      • Synexus Clinical Research US - The Villages- Site Number : 8400011
  • Georgia
    • Atlanta, Georgia, United States, 30328
      • Synexus Clinical Research US - Atlanta- Site Number : 8400001
  • Illinois
    • Chicago, Illinois, United States, 60602
      • Synexus Clinical Research- Site Number : 8400004
  • Missouri
    • Creve Coeur, Missouri, United States, 63141
      • Synexus Clinical Research - St. Louis- Site Number : 8400010
  • New York
    • New York, New York, United States, 10017
      • Synexus Clinical Research - New York- Site Number : 8400007
  • Texas
    • Austin, Texas, United States, 78705
      • Optimal Research - Texas- Site Number : 8400002
    • Dallas, Texas, United States, 75234
      • Synexus Clinical Research US - Dallas- Site Number : 8400005
    • San Antonio, Texas, United States, 78229
      • Synexus Clinical Research US - San Antonio- Site Number : 8400009
  • Utah
    • Salt Lake City, Utah, United States, 84106
      • Synexus Salt Lake City Site Number : 8400008

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

Inclusion criteria to be checked at Screening Visit

• Aged 50 years or older on the day of inclusion
• Informed consent form has been signed and dated.
• Able to attend all scheduled visits and to comply with all study procedures.
• Participant must be able to receive an injection in the deltoid muscle of both arms.
• Participant must have completed a primary vaccination series against SARS-CoV-2 and at least 1 booster with a locally authorized or approved COVID-19 vaccine.

Inclusion criteria to be checked at Visit 1 (D01):

• Aged 50 years or older on the day of inclusion
• Participants who are healthy or with pre-existing stable condition (defined as disease not requiring significant change in therapy or hospitalization for worsening disease during the 12 weeks before enrollment), as determined by medical evaluation including medical history and physical examination.

• 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 post-menopausal 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 4 weeks after 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) on the day of enrollment before the first dose of study intervention.

• Informed consent form has been signed and dated.
• Able to attend all scheduled visits and to comply with all study procedures.
• Participant must be able to receive an injection in the deltoid muscle of both arms.
• Participant must have completed a primary vaccination series against SARS-CoV-2 and at least 1 booster with a locally authorized or approved COVID-19 vaccine.

Exclusion Criteria:

Exclusion criteria to be checked at Screening Visit and at Visit 1 (D01):

• 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 (for glucocorticoids, ≥ 10 milligrams/day of prednisone or equivalent for more than 2 consecutive weeks within the past 3 months).
• Known systemic hypersensitivity to any of the study intervention components, or history of a life-threatening reaction to the study interventions used in the study or to a product containing any of the same substances .
• Self-reported thrombocytopenia, contraindicating intramuscular injection, based on investigator's judgment.
• Bleeding disorder, or receipt of anticoagulants in the 3 weeks preceding inclusion, contraindicating intramuscular injection, based on investigator's judgment.
• Chronic illness (1) 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 judgment) or febrile illness (temperature ≥ 100.4°F) on the day of study intervention administration. 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.
• History of serious adverse reaction to any influenza or COVID-19 vaccines.
• Personal or family history of Guillain-Barré syndrome.
• Prior history of myocarditis, pericarditis, or myopericarditis.
• Prior history of stroke, transient ischemic attack, or stroke risk factors, which may include untreated/uncontrolled hypertension, untreated/uncontrolled hyperlipidemia, active smoking, atrial fibrillation, and additional risk factors, based on investigator's judgment, which may include history of thromboembolic disease, obesity, cardiac structural or valvular abnormality, carotid stent placement, or family history of stroke..
• Receipt of any vaccine in the 4 weeks preceding study intervention administration or planned receipt of any vaccine prior to the second blood draw (ie, approximately in the 28 days following study intervention administration .
• Previous vaccination against influenza (in the previous 6 months) with an investigational or marketed vaccine.
• Previous vaccination against COVID-19 (in the previous 6 months) with an investigational or marketed vaccine OR history of COVID-19 in the previous 6 months .
• Receipt of immune globulins, blood or blood-derived products in the past 3 months.
• 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.
• Deprived of freedom by an administrative or court order, or being in an emergency setting, or hospitalized involuntarily.

• Identified as an Investigator or employee of the Investigator or study center with direct involvement in the proposed study, or identified as an immediate family member (ie, parent, spouse, natural or adopted child) of the Investigator or employee with direct involvement in the proposed study.

  1. Chronic illness may include, but is not limited to, cardiac disorders, hypertension, pulmonary disease, renal disorders, auto-immune disorders, diabetes mellitus, psychiatric disorders, neurologic disorders, or chronic infection

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Quadruple

Number of Arms

7

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Group 2: rC19 (dose 1) (in right or left deltoid) and placebo (in opposite deltoid); two IM injections on D01	Other: Placebo (0.9% NaCl); Normal saline; Biological: rC19 (dose 1); Protein subunit
Experimental: Group 1: IIV-HD (in right or left deltoid) and placebo (in opposite deltoid); two IM injections on D01	Other: Placebo (0.9% NaCl); Normal saline; Biological: IIV-HD; Inactivated, split-virion
Experimental: Group 3: IIV-HD (in right or left deltoid) and rC19 (dose1) (in opposite deltoid); two IM injections on D01	Biological: rC19 (dose 1); Protein subunit; Biological: IIV-HD; Inactivated, split-virion
Experimental: Group 4: IIV-HD + rC19 (dose 1) (in right or left deltoid) and placebo (in opposite deltoid); two IM injections on D01	Other: Placebo (0.9% NaCl); Normal saline; Biological: IIV-HD + rC19 (dose 1); IIV-HD component: Inactivated, split-virion rC19 component: Protein subunit
Experimental: Group 5: IIV-HD + rC19 (dose 2) (in right or left deltoid) and placebo (in opposite deltoid); two IM injections on D01	Other: Placebo (0.9% NaCl); Normal saline; Biological: IIV-HD + rC19 (dose 2); IIV-HD component: Inactivated, split-virion rC19 component: Protein subunit
Experimental: Group 6: IIV-HD + rC19 (dose 3) (in right or left deltoid) and placebo (in opposite deltoid); two IM injections on D01	Other: Placebo (0.9% NaCl); Normal saline; Biological: IIV-HD + rC19 (dose 3); IIV-HD component: Inactivated, split-virion rC19 component: Protein subunit
Experimental: Group 7: IIV-HD + rC19 (dose 4) (in right or left deltoid) and placebo (in opposite deltoid); two IM injections on D01	Other: Placebo (0.9% NaCl); Normal saline; Biological: IIV-HD + rC19 (dose 4); IIV-HD component: Inactivated, split-virion rC19 component: Protein subunit

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of participants with solicited injection site reactions	Solicited injection site reactions include injection site pain, erythema and swelling	Up to 7 each days after vaccination
Number of participants with solicited systemic reactions	Solicited systemic reactions include fever, headache, fatigue, myalgia and chills	Up to 7 days after each vaccination
Number of participants with unsolicited AEs	Unsolicited (spontaneously reported) AEs, not fulfilling criteria for solicited adverse reactions	Up to 28 days after each vaccination
Number of participants with adverse events of special interest (AESIs)	AESIs	Up to 180 days after each vaccination
Number of participants with medical attended adverse events (MAAEs)	MAAEs	Up to 180 days after each vaccination
Number of participants with serious adverse events (SAEs)	SAEs	Up to 180 days after each vaccination
Number of participants with immediate adverse events (AEs)	Immediate adverse events are any unsolicited systemic adverse events reported in the 30 minutes after vaccination	Within 30 minutes after each vaccination
Number of MAAEs relating to predefined potential immune-mediated disease (PIMDs)	MAAEs relating to predefined PIMDs	From D182 through 12 months following the last study vaccination
Number of participants with related SAEs	Related SAEs	From D182 through 12 months following the last study vaccination
Number of MAAEs relating to predefined PIMDs that meet the criteria for SAEs	MAAEs relating to predefined PIMDs that meet the criteria for SAEs	From D182 through 12 months following the last study vaccination
Geometric mean (GM) of HAI titers in all participants	HAI titers	At D01 and D30
Geometric mean ratio (GMR) HAI titers ratio D30/D01 in all participants	Individual HAI titers ratio D30/D01	At D01 and D30
GM of SARS-CoV-2 neutralizing titers in all participants	SARS-CoV-2 neutralizing titers	At D01 and D30
GMR of SARS-CoV-2 neutralizing titers ratio D30/D01 in all participants	Individual SARS-CoV-2 neutralizing titers ratio D30/D01	At D01 and D30

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Percentage of participants with seroconversion in all participants	Seroconversion is defined by: HAI titer < 10 [1/dil] at D01 and post-injection titer ≥ 40 [1/dil] at D30 or HAI titer ≥ 10 [1/dil] and a ≥ 4-fold increase in titer [1/dil] at D30	At D30
Percentage of participants with HAI titer ≥ 10 (1/dil) in all participants	detectable HAI titer ≥ 10 (1/dil)	At D01 and D30
Percentage of participants with HAI titer ≥ 40 (1/dil) in all participants	HAI titer ≥ 40 (1/dil)	At D01 and D30
Percentage of participants with seroresponse to SARS-CoV-2 in all participants	Seroresponse to SARS-CoV-2 is defined by SARS-CoV-2 neutralizing titers ≥ 4-fold rise in SARS-CoV-2 neutralizing titers from D01 to D30	At D30

Collaborators and Investigators

• Sponsor: Sanofi

Publications and helpful links

Helpful Links

• VBT00001 Plain Language Results Summary

Study record dates

Study Major Dates

• Study Start (Actual): November 19, 2024
• Primary Completion (Actual): April 16, 2026
• Study Completion (Actual): April 16, 2026

Study Registration Dates

• First Submitted: November 14, 2024
• First Submitted That Met QC Criteria: November 15, 2024
• First Posted (Actual): November 19, 2024

Study Record Updates

• Last Update Posted (Actual): May 5, 2026
• Last Update Submitted That Met QC Criteria: April 29, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: COVID-19 Vaccine and Influenza Vaccine
• Additional Relevant MeSH Terms: Respiratory Tract Infections; Infections; Orthomyxoviridae Infections; RNA Virus Infections; Virus Diseases; Respiratory Tract Diseases; Influenza, Human
• Other Study ID Numbers: VBT00001; U1111-1310-5034 (Registry Identifier: ICTRP)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: 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

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No