A Study on the Immunogenicity and Safety of 3 Different Dose Concentrations of a Respiratory Syncytial Virus Vaccine in Infants and Toddlers (OPAL)
July 30, 2026 updated by: Sanofi Pasteur, a Sanofi Company
A Parallel Group, Phase III, Randomized, Observer Blind, Placebo Controlled, Multi Center, Multinational, Multi Arm Study to Demonstrate Non-inferiority of the Immune Response of a Low Dose Compared to the Standard Dose and to Evaluate the Safety of a Respiratory Syncytial Virus Vaccine in Infants and Toddlers (OPAL)
This study was a Phase III, parallel group, randomized, observer blind, placebo controlled, multi-national, multi-center, multi-arm study conducted in 42 healthy children enrolled at 6 months to <22 months of age.
The purpose of the study was to evaluate the non-inferiority of the immune response of the lower dose (LD) when compared to the standard dose (SD) respiratory syncytial virus infant and toddler (RSVt) vaccine and the safety of the LD, SD and high dose (HD) vaccine in preterm born children and of the HD vaccine in full term born children administered by intranasal route and compared to placebo.
Study Overview
Status
Terminated
Conditions
Detailed Description
The study duration was approximately 8 months for each participant, including the 6 months safety follow-up phone call after the second study intervention administration.
Study Type
Interventional
Enrollment (Actual)
42
Phase
- Phase 3
Contacts and Locations
This section provides the contact details for those conducting the study, and information on where this study is being conducted.
Study Locations
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-
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San Pedro Sula, Honduras
- Investigational Site Number : 3400002
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Tegucigalpa, Honduras, 11101
- Investigational Site Number : 3400001
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Tegucigalpa, Honduras, 11101
- Investigational Site Number : 3400003
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Participation Criteria
Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.
Eligibility Criteria
Ages Eligible for Study
- Child
Accepts Healthy Volunteers
Yes
Description
Inclusion Criteria:
- Aged 6 months to < 22 months on the day of inclusion (means from the day of the 6-month birthday to the day before the 22-month birthday. The second vaccine administration was administered before the study participant has turned 24 months of age).
- Participants who were healthy as determined by medical evaluation including medical history.
For Cohort 1 and Cohort 2 (contingent upon satisfactory safety profile of the RSVt vaccine in Cohort 1):
--Participant born 28 through 36 weeks of gestation and medically stable as assessed by the investigator, based on the following definition: "Medically stable" refers to the condition of premature infants who do not require significant medical support or ongoing management for debilitating disease and who have demonstrated a clinical course of sustained recovery by the time they receive the first dose of study intervention.
For Cohort 2:
- Participant born at full term of pregnancy (≥ 37 weeks of gestation).
Exclusion Criteria:
Participants were excluded from the study if any of the following criteria apply:
- 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, or history of a life-threatening reaction to the study intervention used in the study or to a product containing any of the same substances.
Chronic illness that, in the opinion of the investigator, is at a stage where it might interfere with study conduct or completion.
- History of medically diagnosed wheezing. Children with a history of recurrent wheezing will be excluded. Children with a previous single episode of wheezing may be included if that episode of wheezing was not associated with hospitalization or if does not have a family history of wheezing.
- Any acute febrile illness in the past 48 hours that according to investigator judgment is significant enough to interfere with successful inoculation 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.
- Probable or confirmed ongoing case of viral respiratory infection (including COVID-19, influenza, rhinovirus, etc.) at the time of enrollment. A prospective participant should not be included in the study until the respiratory infection has resolved.
Member of a household that contains an immunocompromised individual, including, but not limited to:
- a person who is HIV infected
- a person who has received chemotherapy within the 12 months prior to study enrollment
- a person who has received (within the past 6 months) or is receiving (at the time of enrollment) immunosuppressant agents
- a person living with a solid organ or bone marrow transplant
- Potential close contact with other immunocompromised individual within 30 days after each vaccination as per investigator's discretion.
- Participant's biological mother's previous receipt or planned administration of an investigational RSV vaccine during pregnancy and/or breastfeeding.
Receipt or planned receipt of any of the following vaccines prior to enrollment or after the first study intervention administration:
- Any other intranasal live attenuated vaccine within the 28 days prior to and after Dose 1 study administration
- Unless given on the day of the first study intervention administration, any other injectable live attenuated vaccines within the 28 days prior to and after. Concomitant receipt on the day of the first study intervention administration is allowed
- Planned receipt of any monoclonal antibody for RSV (such as Nirsevimab or Palivizumab) for the duration of the study.
- Previous receipt of an investigational RSV vaccine or receiving any anti-RSV product (such as ribavirin or RSV immune globulin) at the time of enrollment. Previous receipt of an RSV monoclonal antibody within 6 months prior to the first study vaccine administration.
- Receipt of immune globulins, blood or blood-derived products in the past 3 months
- Receipt of intranasal and intra-ocular medications within 3 days prior to study enrollment
- Participation at the time of study enrollment or planned participation during the present study period in another clinical study investigating a vaccine, drug, medical device, or medical procedure
Note: The above information is not intended to contain all considerations relevant to a potential participation in a clinical trial.
Study Plan
This section provides details of the study plan, including how the study is designed and what the study is measuring.
How is the study designed?
Design Details
- Primary Purpose: Prevention
- Allocation: Randomized
- Interventional Model: Parallel Assignment
- Masking: Triple
Arms and Interventions
Participant Group / Arm |
Intervention / Treatment |
|---|---|
|
Experimental: Cohort 1: Group 1- (SD RSVt vaccine)
Participants received 2 intranasal administrations of SD RSVt vaccine
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Pharmaceutical form:Liquid for nasal spray-Route of administration:Intranasal
Other Names:
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Placebo Comparator: Cohort 1: Group 2-Control
Participants received 2 intranasal administrations of placebo
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Pharmaceutical form:Liquid for nasal spray-Route of administration:Intranasal
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Experimental: Cohort 1: Group 3- (HD RSVt vaccine)
Participants received 2 intranasal administrations of HD RSVt vaccine
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Pharmaceutical form:Liquid for nasal spray-Route of administration:Intranasal
Other Names:
|
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Placebo Comparator: Cohort 1: Group 4-Control
Participants received 2 intranasal administrations of placebo
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Pharmaceutical form:Liquid for nasal spray-Route of administration:Intranasal
|
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Experimental: Cohort 2: Group 1- (LD RSVt vaccine)
Participants received 2 intranasal administrations of LD RSVt vaccine
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Pharmaceutical form: Liquid for nasal spray Route of administration: Intranasal
Other Names:
|
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Experimental: Cohort 2: Group 2- (SD RSVt vaccine)
Participants received 2 intranasal administrations of SD RSVt vaccine
|
Pharmaceutical form:Liquid for nasal spray-Route of administration:Intranasal
Other Names:
|
|
Experimental: Cohort 2: Group 3- (HD RSVt vaccine
Participants received 2 intranasal administrations of HD RSVt vaccine
|
Pharmaceutical form:Liquid for nasal spray-Route of administration:Intranasal
Other Names:
|
|
Placebo Comparator: Cohort 2: Group 4-Control
Participants received 2 intranasal administrations of placebo
|
Pharmaceutical form:Liquid for nasal spray-Route of administration:Intranasal
|
What is the study measuring?
Primary Outcome Measures
Outcome Measure |
Measure Description |
Time Frame |
|---|---|---|
|
Cohort 2: Geometric Mean Titers (GMT) of RSV A Serum Neutralizing Antibodies at Day 85 (Post-Dose 2)
Time Frame: Day 85 (28 days post-vaccination 2)
|
Serum samples were planned to be collected at specified timepoints for immunogenicity assessments.
RSV A serum neutralizing antibody titers were planned to be determined using a validated plaque reduction neutralization test (PRNT).
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Day 85 (28 days post-vaccination 2)
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Cohort 2: Geometric Mean Titers of RSV B Serum Neutralizing Antibodies at Day 85 (Post-Dose 2)
Time Frame: Day 85 (28 days post-vaccination 2)
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Serum samples were planned to be collected at specified timepoints for immunogenicity assessments.
RSV B serum neutralizing antibody titers were planned to be determined using a validated PRNT.
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Day 85 (28 days post-vaccination 2)
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Cohorts 1 and 2: Number of Participants With Immediate Unsolicited Systemic Adverse Events (AEs)
Time Frame: Up to 30 minutes after each vaccination (post-dose on Day 1)
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An AE was any untoward medical occurrence in a clinical study participant temporally associated with the use of study vaccine, whether or not considered related to the study vaccine.
An unsolicited AE was an observed AE that did not fulfill the conditions of solicited reactions, i.e., pre-listed in the case report form (CRF) in terms of diagnosis and onset window post-vaccination.
All participants were observed for 30 minutes after each vaccination and any unsolicited AEs that occurred during that time were recorded as immediate unsolicited AEs.
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Up to 30 minutes after each vaccination (post-dose on Day 1)
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Cohorts 1 and 2: Number of Participants With Solicited Administration Site Reactions
Time Frame: Up to 21 days after each vaccination (post-dose on Day 1)
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A solicited injection/administration site reactions were adverse reactions (AR) at and around the injection/administration site of the study vaccine observed and reported under the conditions (nature and onset) pre-listed in the protocol and CRF and considered as related to the study vaccine administered.
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Up to 21 days after each vaccination (post-dose on Day 1)
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Cohorts 1 and 2: Number of Participants With Solicited Systemic Reactions
Time Frame: Up to 21 days after each vaccination (post-dose on Day 1)
|
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 and considered as related to the study vaccine administered.
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Up to 21 days after each vaccination (post-dose on Day 1)
|
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Cohorts 1 and 2: Number of Participants With Unsolicited Adverse Events
Time Frame: Up to 28 days after each vaccination (post-dose on Day 1)
|
An unsolicited AE was an observed AE that did not fulfill the conditions of solicited reactions, that is, pre-listed in the CRF in terms of diagnosis and onset window post-vaccination.
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Up to 28 days after each vaccination (post-dose on Day 1)
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Cohorts 1 and 2: Number of Participants With Medically Attended Adverse Events (MAAEs)
Time Frame: From first dose of study vaccine administration (Day 1) to 198 days
|
An MAAE was defined as a new onset or a worsening of a condition that prompted the participant or participant's parent/legally acceptable representative to seek unplanned medical advice at a physician's office or emergency department.
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From first dose of study vaccine administration (Day 1) to 198 days
|
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Cohorts 1 and 2: Number of Participants With Serious Adverse Events (SAEs)
Time Frame: From first dose of study vaccine administration (Day 1) to 198 days
|
An SAE was defined as 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 other medically important event.
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From first dose of study vaccine administration (Day 1) to 198 days
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Cohorts 1 and 2: Number of Participants With Adverse Events of Special Interest (AESIs)
Time Frame: From first dose of study vaccine administration (Day 1) to 198 days
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An AESI (serious or non-serious) was one of scientific and medical concern specific to the sponsor's study vaccine or program, for which ongoing monitoring and rapid communication by the investigator to the sponsor was appropriate.
Acute wheeze and anaphylaxis were collected as AESI.
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From first dose of study vaccine administration (Day 1) to 198 days
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Secondary Outcome Measures
Outcome Measure |
Measure Description |
Time Frame |
|---|---|---|
|
Cohort 1: Geometric Mean Titers of RSV A and B Serum Neutralizing Antibodies at Baseline (Day 1) and Day 85
Time Frame: Baseline (Day 1) and Day 85
|
Serum samples were planned to be collected at specified timepoints for immunogenicity assessments.
RSV A and RSV B serum neutralizing antibody titers were planned to be determined using a validated PRNT.
|
Baseline (Day 1) and Day 85
|
|
Cohorts 1 and 2: Mean Titers of RSV Serum Anti-F Immunoglobulin (Ig) A and IgG Antibodies at Baseline (Day 1) and Day 85
Time Frame: Baseline (Day 1) and Day 85
|
Serum samples were collected at specified timepoints for immunogenicity assessments.
Antibodies to RSV F antigen were measured using the anti-RSV serum anti-F IgA and IgG using electrochemiluminescence method.
Log10 titer values are reported.
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Baseline (Day 1) and Day 85
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Cohorts 1 and 2: Percentage of Participants With Quantified Shedding >=3.37 Lower Limit of Quantitation (LLOQ)
Time Frame: Day 8 and Day 64
|
Nasal swabs were collected to assess shedding of the attenuated RSV vaccine strain at specified timepoints.
Quantitative reverse transcription polymerase chain reaction (qRT-PCR) assay was developed to detect and quantify RSV ΔNS2 candidate in nasal swab samples.
Percentages rounded off to tenth decimal place.
|
Day 8 and Day 64
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Cohorts 1 and 2: Percentage of Participants With Detectable Shedding >=2.08 Limit of Detection
Time Frame: Day 8 and Day 64
|
Nasal swabs were collected to assess shedding of the attenuated RSV vaccine strain at specified timepoints.
qRT-PCR assay was developed to detect and quantify RSV ΔNS2 candidate in nasal swab samples.
Percentages rounded off to tenth decimal place.
|
Day 8 and Day 64
|
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Cohorts 1 and 2: Titer of Vaccine Virus Shedding in Participants Detected in Nasal Samples Quantified by Quantitative Real Time-Polymerase Chain Reaction
Time Frame: Day 8 and Day 64
|
Nasal swabs were collected to assess shedding of the attenuated RSV vaccine strain at specified timepoints.
qRT-PCR assay was developed to detect and quantify RSV ΔNS2 candidate in nasal swab samples.
Quantified virus shedding was defined as vaccine virus shedding >=lower limit of quantification (LLOQ=3.37 log10 copies/mL).
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Day 8 and Day 64
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Collaborators and Investigators
This is where you will find people and organizations involved with this study.
Sponsor
Publications and helpful links
The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.
Helpful Links
Study record dates
These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.
Study Major Dates
Study Start (Actual)
November 25, 2024
Primary Completion (Actual)
June 11, 2025
Study Completion (Actual)
June 11, 2025
Study Registration Dates
First Submitted
November 22, 2024
First Submitted That Met QC Criteria
November 22, 2024
First Posted (Actual)
November 26, 2024
Study Record Updates
Last Update Posted (Actual)
August 3, 2026
Last Update Submitted That Met QC Criteria
July 30, 2026
Last Verified
July 1, 2026
More Information
Terms related to this study
Keywords
Additional Relevant MeSH Terms
Other Study ID Numbers
- VAD00015
- 2023-509536-26 (Registry Identifier: CTIS)
- U1111-1298-7338 (Registry Identifier: WHO 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
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