Study on an Investigational Yellow Fever Vaccine Compared With Stamaril in Adults in Europe and Asia

Controlled Study of Immunogenicity and Safety of the Investigational vYF Candidate Vaccine in Comparison to Stamaril in Adults

VYF03 is a phase II, randomized, parallel-group prevention study with 2 arms, active-controlled (Stamaril), observer-blind, multi-center study to assess the non-inferiority of the immune response, in terms of seroconversion rates of the investigational vaccine candidate vYF to the licensed Stamaril, in adults aged 18 years up to 60 years in Europe (EU).

The safety and immunogenicity profile of vYF in a cohort of Asian population of Chinese origin outside of China will also be described. The study will also assess the immunogenicity profiles and the safety profiles of vYF and Stamaril.

Participants will be randomized in a 2:1 ratio to receive a single subcutaneous injection of either the vYF vaccine (380 participants in EU and 80 participants of Chinese origin in Asia) or Stamaril (190 participants in EU and 40 participants of Chinese origin in Asia), on Day 01.

The duration of each participant's participation will be approximately 5 years.

Study Overview

• Status: Active, not recruiting
• Conditions: Yellow Fever
• Intervention / Treatment: Biological: Yellow fever vaccine (produced on serum-free Vero cells); Biological: Yellow fever vaccine

Detailed Description

The duration of each participant's participation will be approximately 5 years.

• Study Type: Interventional
• Enrollment (Actual): 690
• Phase: Phase 2

Contacts and Locations

Study Locations

• Finland
  • Helsinki, Finland, 00290
    • Investigational Site Number : 2460001
  • Tampere, Finland, 33100
    • Investigational Site Number : 2460002
  • Turku, Finland, 20520
    • Investigational Site Number : 2460003
• France
  • Lyon, France, 69004
    • Investigational Site Number : 2500008
  • Montpellier, France, 34295
    • Investigational Site Number : 2500006
  • Nantes, France, 44093
    • Investigational Site Number : 2500001
  • Nîmes, France, 30029
    • Investigational Site Number : 2500007
  • Paris, France, 75014
    • Investigational Site Number : 2500009
  • Pierre-Bénite, France, 69495
    • Investigational Site Number : 2500004
• Germany
  • Berlin, Germany, 10117
    • Investigational Site Number : 2760004
  • Hamburg, Germany, 20359
    • Investigational Site Number : 2760001
  • München, Germany, 80802
    • Investigational Site Number : 2760002
  • Rostock, Germany, 18057
    • Investigational Site Number : 2760003
• Singapore
  • Singapore, Singapore, 119074
    • Investigational Site Number : 7020002
  • Singapore, Singapore, 169608
    • Investigational Site Number : 7020003
  • Singapore, Singapore
    • Investigational Site Number : 7020001
• Spain
  • Barcelona, Spain, 08036
    • Investigational Site Number : 7240001
  • Barcelona [Barcelona]
    • Barcelona, Barcelona [Barcelona], Spain, 08035
      • Investigational Site Number : 7240004
    • L'Hospitalet de Llobregat, Barcelona [Barcelona], Spain, 08907
      • Investigational Site Number : 7240003
  • Madrid, Comunidad de
    • Madrid, Madrid, Comunidad de, Spain, 28046
      • Investigational Site Number : 7240002
• Thailand
  • Bangkok, Thailand, 10330
    • Investigational Site Number : 7640001
  • Bangkok, Thailand
    • Investigational Site Number : 7640002
  • Nonthaburi, Thailand, 11000
    • Investigational Site Number : 7640003

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 59 years (Adult)
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Aged 18 years up to 60 years* 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 (1) or abstinence (1) from at least 4 weeks prior to study intervention administration until at least 4 weeks (2) after study intervention administration.

*18 to 60 years means from the day of the 18th birthday up to the day before the 60th birthday

1. Not applicable for Finland

2. Except for French participants which have to apply 12 weeks contraception 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) before any dose of study intervention on Day 1 and the test will be repeated on D29 to confirm the participant is still not pregnant within 28 days of vaccine administration.

   - Informed consent form has been signed and dated (3)

3. For participants aged less than 21 years in Singapore, an informed consent form has been signed and dated by both the participant and the parent(s) or another legally acceptable representative

   • Able to attend all scheduled visits and to comply with all study procedures
   • For participants enrolled in Asian countries as part of the additional cohort only: know Chinese origin, defined as having at least one biological parent of Chinese origin, and will be self-reported by the participant

   Exclusion Criteria:

   Participation at the time of study enrollment (or in the 4 weeks preceding the study vaccination) or planned participation during the first 2 years of the 5-year follow-up in another clinical study investigating a vaccine, drug, medical device, or medical procedure. Enrollment in another study after the first 2 years is permitted, assuming that it does not exclude participation in this study.

   • Receipt of any vaccine in the 4 weeks preceding the study vaccination or planned receipt of any vaccine in the 4 weeks following the study vaccination (prior to visit 4), except for influenza vaccination, which may be received at least 2 weeks before study vaccines (4). This exception includes all influenza vaccines including monovalent pandemic influenza vaccines.
   • Previous vaccination against a FV disease at any time including YF with either the study vaccine or another vaccine.
   • Receipt of immune globulins, blood, or blood-derived products in the past 6 months.
   • 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 history of any FV infection.
   • Known systemic hypersensitivity to any of the vaccine components, eggs, or history of a life-threatening reaction to the vaccines used in the study or to a vaccine containing any of the same substances.
   • Known history or laboratory evidence of HIV infection (5).
   • Known history or laboratory evidence of hepatitis B or hepatitis C infection (6).
   • Personal or family history of thymic pathology (thymoma, thymectomy, or myasthenia).
   • Deprived of freedom by an administrative or court order, or in an emergency setting, or hospitalized involuntarily.
   • Alcohol, prescription drug, or substance abuse that, in the opinion of the Investigator, might interfere with the study conduct or completion.
   • Chronic illness (7) that, in the opinion of the Investigator, is at a stage where it might interfere with trial conduct or completion, including malignancy, such as leukemia, or lymphoma.
   • Moderate or severe acute illness/infection (according to Investigator judgment) on the day of vaccination or febrile illness (temperature ≥ 100.4°F or 38°C). A prospective participant should not be included in the study until the condition has resolved or the febrile event has subsided.
   • Administration of any anti-viral within 2 months preceding the vaccination and planned administration up to the 6 weeks following the vaccination.
   • 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.
   • Planned travel in a YF endemic country within 6 months of investigational or control vaccine administration.
4. Except for Thai participants
5. HIV Serology testing will be performed on all German participants if no evidence of seronegativity in the 90 days preceding vaccination
6. Hepatitis B and Hepatitis C Serology testing will be performed on all German participants if no evidence of seronegativity in the 90 days preceding vaccination
7. Chronic illness may include, but is not limited to, cardiac disorders, renal disorders, auto-immune disorders, diabetes, psychiatric 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

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Group 1; 1 injection of vYF vaccine at Day 1	Biological: Yellow fever vaccine (produced on serum-free Vero cells); Powder and diluent for suspension for injection - Subcutaneous; Other Names: vYF vaccine
Active Comparator: Group 2; 1 injection of Stamaril vaccine at Day 1	Biological: Yellow fever vaccine; Powder and diluent for suspension for injection - Subcutaneous; Other Names: Stamaril

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Percentage of Yellow Fever-naive Participants Who Achieved Seroconversion 28 Days Post Dose 1 Enrolled in European Union	Seroconversion was defined as a 4-fold increase in Nab titers as compared to the pre-vaccination value. YF-naive participants (or negative) at baseline corresponded to participants with no detectable YF Ab titers before vaccination. The YF NAb titers were determined using a validated live virus microneutralization (MN) assay. Percentages are rounded off to the tenth decimal place.	28 days post dose 1 (Day 29)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Percentage of Participants Who Achieved Seroconversion 28 Days Post Dose 1 Enrolled in European Union	Seroconversion was defined as a 4-fold increase in Nab titers as compared to the pre-vaccination value. The YF NAb titers were determined using a validated live virus MN assay. Percentages are rounded off to the tenth decimal place.	28 days post dose 1 (Day 29)
Percentage of Participants Who Achieved Seroconversion Enrolled in European Union and Asia	Seroconversion was defined as a 4-fold increase in Nab titers as compared to the pre-vaccination value: as compared to the Day 1 titers at each timepoint up to Month 6; as compared to the last planned previous timepoint from Year 1 onwards. The YF NAb titers were determined using a validated live virus MN assay. Percentages are rounded off to the tenth decimal place.	Days 1, 11, 29, Month 6, Years 1 and 2
Percentage of Participants Who Achieved Seroprotection to Yellow Fever Virus Enrolled in European Union and Asia	Seroprotection was defined as NAb titers >=threshold of 10 (1/dilution). YF-naive participants (or negative) at baseline corresponded to participants with no detectable YF Ab titers before vaccination. The YF NAb titers were determined using a validated live virus MN assay. Percentages are rounded off to the tenth decimal place.	Days 1, 11, 29, Month 6, Years 1 and 2
Geometric Mean Titers (GMTs) of Antibodies Against Yellow Fever Virus in Participants Enrolled in European Union and Asia	GMTs of antibody against YF virus was measured using a validated live virus MN assay.	Days 1, 11, 29, Month 6, Years 1 and 2
Geometric Mean Titers Ratio (GMTRs) of Antibodies Against Yellow Fever Virus in Participants Enrolled in European Union and Asia	GMTs of antibody against YF virus was measured using a validated live virus MN assay. Ratio was calculated as post-vaccination titer at Days 11, 29 and Month 6 to pre-vaccination titer at Day 1; post-vaccination titer at Year 1 to pre-vaccination titer at Month 6; post-vaccination titer at Year 2 to pre-vaccination titer at Year 1.	Days 1, 11, 29, Month 6, Years 1 and 2
Number of Participants With Unsolicited Systemic Adverse Events (AEs)	An unsolicited AE was an observed AE that did not fulfill the conditions of solicited reactions, ie, pre-listed in the CRF in terms of diagnosis and onset window post-vaccination.	Up to 30 minutes post vaccination on Day 1
Number of Participants With Solicited Injection Site Reactions	A solicited reaction was an "expected" adverse reaction (AR) (sign or symptom) observed and reported under the conditions (nature and onset) pre-listed in the protocol and CRF. An injection site reaction was an AR at and around the injection site of the study vaccine.	Up to 7 days post vaccination (Day 8)
Number of Participants With Solicited Systemic Reactions	A solicited reaction was an "expected" AR (sign or symptom) observed and reported under the conditions (nature and onset) pre-listed in the protocol and CRF. Solicited systemic reactions were systemic AEs observed and reported under the conditions (nature and onset) pre-listed in the protocol and CRF.	Up to 14 days post vaccination (Day 15)
Number of Participants With Unsolicited Adverse Events	An unsolicited AE was an observed AE that did not fulfill the conditions of solicited reactions, ie, pre-listed in the CRF in terms of diagnosis and onset window post-vaccination.	Up to 28 days post vaccination (Day 29)
Number of Participants With Any Serious Adverse Events (SAEs) and Adverse Events of Special Interest (AESIs) up to 6 Months Post-Vaccination	An SAE was any AE that at any dose resulted in death, was life-threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, was a congenital anomaly/birth defect, or was an important medical event. An AESI (serious or non-serious) was defined as one of scientific and medical concern specific to the Sponsor's study intervention or program, for which ongoing monitoring and rapid communication by the Investigator to the Sponsor could be appropriate. AESIs included serious hypersensitivity/allergic reactions, organ failure/serious viscerotropic events, serious neurologic events.	From the first dose of study vaccine administration (Day 1) up to 6 months post vaccination, approximately up to Day 181
Number of Participants With Serious Adverse Events and Deaths up to Day 1030	An SAE was any AE that at any dose resulted in death, was life-threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, was a congenital anomaly/birth defect, or was an important medical event.	From the first dose of study vaccine administration (Day 1) up to DBL date of 01 August 2024, approximately up to Day 1030
Number of Participants With Serious Adverse Events and Deaths Up to Year 5	An SAE was any AE that at any dose resulted in death, was life-threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, was a congenital anomaly/birth defect, or was an important medical event.	From the first dose of study vaccine administration (Day 1) up to end of study, approximately 5 years

Collaborators and Investigators

• Sponsor: Sanofi Pasteur, a Sanofi Company
• Investigators: Study Director: Clinical Sciences & Operations, Sanofi

Publications and helpful links

Helpful Links

• VYF03 Plain Language Results Summary

Study record dates

Study Major Dates

• Study Start (Actual): October 7, 2021
• Primary Completion (Actual): May 23, 2022
• Study Completion (Estimated): April 23, 2027

Study Registration Dates

• First Submitted: August 17, 2021
• First Submitted That Met QC Criteria: August 17, 2021
• First Posted (Actual): August 18, 2021

Study Record Updates

• Last Update Posted (Actual): June 1, 2026
• Last Update Submitted That Met QC Criteria: May 12, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Vector Borne Diseases; Mosquito-Borne Diseases; Infections; RNA Virus Infections; Virus Diseases; Arbovirus Infections; Flavivirus Infections; Flaviviridae Infections; Hemorrhagic Fevers, Viral; Yellow Fever; Biological Products; Complex Mixtures; Vaccines; Viral Vaccines; Yellow Fever Vaccine
• Other Study ID Numbers: VYF03; U1111-1260-4650 (Registry Identifier: ICTRP); 2020-005566-33 (EudraCT Number); 2022-502047-35 (Registry Identifier: CTIS)

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