Study of an Live-Attenuated Respiratory Syncytial Virus Vaccine in Infants and Toddlers

NCT ID: NCT04491877

Last Updated: 2025-09-09

Study Results

Results available

Outcome measurements, participant flow, baseline characteristics, and adverse events have been published for this study.

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Basic Information

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Recruitment Status

COMPLETED

Clinical Phase

PHASE1/PHASE2

Total Enrollment

259 participants

Study Classification

INTERVENTIONAL

Study Start Date

2020-09-17

Study Completion Date

2023-04-13

Brief Summary

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The primary objectives of the study were:

* To assess the safety profile of each dose of the study product after each and any administration in all infants and toddlers regardless of baseline serostatus.
* To characterize the Respiratory Syncytial Virus (RSV) A serum neutralizing antibody responses to the study product in each vaccine group after vaccination in RSV-naïve participants.

The secondary objectives of the study were:

* To quantify the amount of vaccine virus shed by each participant by baseline serostatus.
* To determine the proportion of vaccinated infants and toddlers in each vaccine group infected with the vaccine virus at D56 (56 days after vaccination 1) for Cohorts 1, 2, 3 and 4, and at Day 84 (28 days after vaccination 2) for Cohorts 2 and 4 by baseline serostatus.
* To characterize the RSV A serum neutralizing antibody responses to the study product in each vaccine group after vaccination in RSV-experienced participants.
* To characterize serum RSV anti-F immunoglobulin G (IgG) antibody responses to the study product in each vaccine group after vaccination by baseline serostatus.
* To characterize serum RSV antibody responses (RSV A-neutralizing and anti-RSV F IgG) to the study product in each vaccine group after the RSV surveillance season or at least 5 months after the last vaccine administration by baseline serostatus.

Detailed Description

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Study duration per participant was maximum 12 months

Conditions

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Respiratory Syncytial Virus Infection

Study Design

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Allocation Method

RANDOMIZED

Intervention Model

SEQUENTIAL

Primary Study Purpose

PREVENTION

Blinding Strategy

QUADRUPLE

Participants Caregivers Investigators Outcome Assessors
The study was performed in an observer-blind fashion. Investigators and study staff who conducted the safety assessment and the participants did not know which vaccine is administered. Only the study staff who prepare and administer the vaccine and were not involved with the safety evaluation knew which vaccine was administered.

Study Groups

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Cohort 1 (RSV vaccine formulation 1)

1 administration of RSV vaccine formulation 1 on Day 0

Group Type EXPERIMENTAL

RSV vaccine formulation 1

Intervention Type BIOLOGICAL

Pharmaceutical form: Suspension of virus Route of administration: Intranasal

Cohort 1 (Placebo)

1 administration of placebo on Day 0

Group Type PLACEBO_COMPARATOR

Placebo

Intervention Type BIOLOGICAL

Pharmaceutical form: Suspension Route of administration: Intranasal

Cohort 2 (RSV vaccine formulation 1)

2 administrations of RSV vaccine formulation 1 on Day 0 and Day 56

Group Type EXPERIMENTAL

RSV vaccine formulation 1

Intervention Type BIOLOGICAL

Pharmaceutical form: Suspension of virus Route of administration: Intranasal

Cohort 2 (Placebo)

2 administrations of placebo on Day 0 and Day 56

Group Type PLACEBO_COMPARATOR

Placebo

Intervention Type BIOLOGICAL

Pharmaceutical form: Suspension Route of administration: Intranasal

Cohort 3 (RSV vaccine formulation 2)

1 administration of RSV vaccine formulation 2 on Day 0

Group Type EXPERIMENTAL

RSV vaccine formulation 2

Intervention Type BIOLOGICAL

Pharmaceutical form: Suspension of virus Route of administration: Intranasal

Cohort 3 (Placebo)

1 administration of placebo on Day 0

Group Type PLACEBO_COMPARATOR

Placebo

Intervention Type BIOLOGICAL

Pharmaceutical form: Suspension Route of administration: Intranasal

Cohort 4 (RSV vaccine formulation 1)

2 administrations of RSV vaccine formulation 1 on Day 0 and Day 56

Group Type EXPERIMENTAL

RSV vaccine formulation 1

Intervention Type BIOLOGICAL

Pharmaceutical form: Suspension of virus Route of administration: Intranasal

Cohort 4 (RSV vaccine formulation 2)

2 administrations of RSV vaccine formulation 2 on Day 0 and Day 56

Group Type EXPERIMENTAL

RSV vaccine formulation 2

Intervention Type BIOLOGICAL

Pharmaceutical form: Suspension of virus Route of administration: Intranasal

Cohort 4 (Placebo)

2 administrations of placebo on Day 0 and Day 56

Group Type PLACEBO_COMPARATOR

Placebo

Intervention Type BIOLOGICAL

Pharmaceutical form: Suspension Route of administration: Intranasal

Interventions

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RSV vaccine formulation 1

Pharmaceutical form: Suspension of virus Route of administration: Intranasal

Intervention Type BIOLOGICAL

RSV vaccine formulation 2

Pharmaceutical form: Suspension of virus Route of administration: Intranasal

Intervention Type BIOLOGICAL

Placebo

Pharmaceutical form: Suspension Route of administration: Intranasal

Intervention Type BIOLOGICAL

Eligibility Criteria

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Inclusion Criteria

* Aged 6 through 18 months at Day 0.
* Informed consent form has been signed and dated by the parent(s) or other legally acceptable representative (and by independent witness if required by local regulations).
* Participant and parent / guardian / legally acceptable representative are able to attend all scheduled visits and to comply with all trial procedures

Exclusion Criteria

* Born at less than 34 weeks gestation
* Born at less than 37 weeks gestation and less than 1 year of age at the time
* 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).
* Probable or confirmed case of Coronavirus Disease 2019 (COVID-19).
* Known systemic hypersensitivity to any of the vaccine components, or history of a life-threatening reaction to the vaccine used in the trial or to a vaccine containing any of the same substances
* Any chronic illness

• Chronic illness may include, but is not limited to, cardiac disorders, lung disease (including any history of reactive airway disease, receipt of bronchodilator therapy, or medically diagnosed wheezing), renal disorders, auto-immune disorders, diabetes, psychomotor diseases, and known congenital or genetic diseases
* Any history of medically diagnosed wheezing
* Any acute febrile, respiratory or gastrointestinal illness in the past 24 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
* Any previous anaphylactic reaction
* Current suspected or documented developmental disorder, delay, or other developmental problem
* Receipt of any of the following vaccines prior to enrollment:

* any influenza vaccine within 7 days prior, or
* any inactivated vaccine or live-attenuated rotavirus vaccine within the 14 days prior, or
* any live vaccine, other than rotavirus vaccine, within the 28 days prior, or
* another investigational vaccine or investigational drug within 28 days prior
* Previous receipt of a licensed or investigational RSV vaccine or previous receipt or planned administration of any anti-RSV product (such as ribavirin or RSV immune immune globulins \[IG\] or RSV monoclonal antibody)
* Receipt of immune globulins, blood or blood-derived products in the past 6 months prior to enrolment
* Receipt of any of the following medications within 3 days prior to study enrollment (Day 0):

* systemic antibacterial, antiviral, antifungal, anti-parasitic, or antituberculous agents, whether for treatment or prophylaxis, or
* intranasal medications, or
* other prescription medication except as permitted concomitant medications (prescription or non-prescription) including nutritional supplements, medications for gastroesophageal reflux, eye drops, and topical medications, including (but not limited to) cutaneous (topical) steroids, topical antibiotics, and topical antifungal agents
* Receipt of salicylate (aspirin) or salicylate-containing products within the 28 days prior to enrollment (Day 0)
* Any previous vaccine-associated adverse reaction that was Grade 3 or above. Note: if grading is not possible, determine if the reaction was considered severe or life threatening; if so, it is exclusionary.
* Scheduled administration of the following after planned inoculation:

* any influenza vaccine within 7 days after, or
* inactivated vaccine or live-attenuated rotavirus vaccine within the 14 days after, or
* any live vaccine other than rotavirus in the 28 days after, or
* another investigational vaccine or investigational drug in the 56 days after.
* Any previous receipt of supplemental oxygen therapy in a home or hospital setting, except the temporary receipt of supplemental oxygen for transient tachypnea in newborn
* 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 enrollment
* a person receiving immunosuppressant agents
* a person living with a solid organ or bone marrow transplant
* Participation at the time of study enrollment (or in the 6 weeks preceding the first trial vaccination) or planned participation during the present trial period in another clinical trial investigating a vaccine, drug, medical device, or medical procedure
* Member of a household that contains, or will contain, an infant who is less than 6 months of age at the enrollment date (or in the 6 weeks preceding the first trial vaccination) through Day 28
* Member of a household that contains another child/other children who is/are, or is/are scheduled to be, enrolled in this study in the same year AND the date of enrollment will not be concurrent with the other participant(s) living in the household (i.e., all eligible children from the same household must be enrolled on the same date)
* Attends a daycare facility and shares a daycare room with infants less than 6 months of age, and parent/guardian is unable or unwilling to suspend daycare for 28 days following inoculation
* Deprived of freedom in an emergency setting or hospitalized involuntarily
* Identified as a natural or adopted child of the Investigator or employee with direct involvement in the proposed study

The above information was not intended to contain all considerations relevant to a participant's potential participation in a clinical trial.
Minimum Eligible Age

6 Months

Maximum Eligible Age

18 Months

Eligible Sex

ALL

Accepts Healthy Volunteers

Yes

Sponsors

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Sanofi Pasteur, a Sanofi Company

INDUSTRY

Sponsor Role lead

Responsible Party

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Responsibility Role SPONSOR

Principal Investigators

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Clinical Sciences & Operations

Role: STUDY_DIRECTOR

Sanofi Pasteur, a Sanofi Company

Locations

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Matrix Clinical Research-Site Number:8400012

Gardena, California, United States

Site Status

Paradigm Clinical Research-Site Number:8400026

La Mesa, California, United States

Site Status

Matrix Clinical Research-Site Number:8400032

Los Angeles, California, United States

Site Status

California Research Foundation-Site Number:8400016

San Diego, California, United States

Site Status

Elite Clinical Trials, Inc.-Site Number:8400001

Blackfoot, Idaho, United States

Site Status

Leavitt Clinical Research-Site Number:8400036

Idaho Falls, Idaho, United States

Site Status

Snake River Research-Site Number:8400022

Idaho Falls, Idaho, United States

Site Status

The South Bend Clinic Center for Research-Site Number:8400024

South Bend, Indiana, United States

Site Status

Alliance for Multispeciality Research-Site Number:8400014

El Dorado, Kansas, United States

Site Status

AMR - Newton-Site Number:8400002

Newton, Kansas, United States

Site Status

Michael W. Simon, MD, PSC-Site Number:8400013

Lexington, Kentucky, United States

Site Status

Benchmark Research-Site Number:8400006

Covington, Louisiana, United States

Site Status

Nola Research Works-Site Number:8400017

New Orleans, Louisiana, United States

Site Status

Clinical Research Institute-Site Number:8400053

Minneapolis, Minnesota, United States

Site Status

Boeson Research-Site Number:8400011

Missoula, Montana, United States

Site Status

Be Well Clinical Studies-Site Number:8400054

Lincoln, Nebraska, United States

Site Status

Meridian Clinical Research - Norfolk-Site Number:8400005

Norfolk, Nebraska, United States

Site Status

MedPharmics Inc-Site Number:8400040

Albuquerque, New Mexico, United States

Site Status

East Carolina University/Brody Medical Sciences Building-Site Number:8400043

Greenville, North Carolina, United States

Site Status

Coastal Pediatric Research-Site Number:8400031

Charleston, South Carolina, United States

Site Status

Tribe Clinical Research-Site Number:8400027

Greenville, South Carolina, United States

Site Status

FMC Science-Site Number:8400042

Lampasas, Texas, United States

Site Status

JBR Clinical Research-Site Number:8400041

Salt Lake City, Utah, United States

Site Status

Pediatric Associates of Charlottesville North-Site Number:8400007

Charlottesville, Virginia, United States

Site Status

National Clinical Research Inc-Site Number:8400004

Richmond, Virginia, United States

Site Status

Investigational Site Number :1520001

Santiago, Reg Metropolitana de Santiago, Chile

Site Status

Investigational Site Number :1520004

Santiago, Reg Metropolitana de Santiago, Chile

Site Status

Investigational Site Number :3400001

San Pedro Sula, , Honduras

Site Status

Investigational Site Number :3400002

Tegucigalpa, , Honduras

Site Status

Countries

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United States Chile Honduras

References

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Idoko OT, Vargas SL, Bueso A, Rivera D, Edward H, Simon M, Banooni P, Berger S, Janicot S, Vercasson C, Pallardy S, Nteene R, Adhikarla H, Gerchman E, Gasparotto M, Gallichan S, Rivas E, Buchholz UJ, Collins PL, Sesay S, Gurunathan S, De Bruijn I, Dhingra MS. Live-Attenuated Intranasal RSV Vaccine in Infants and Toddlers. NEJM Evid. 2025 Sep;4(9):EVIDoa2500026. doi: 10.1056/EVIDoa2500026. Epub 2025 Aug 26.

Reference Type DERIVED
PMID: 40856556 (View on PubMed)

Provided Documents

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Document Type: Study Protocol

View Document

Document Type: Statistical Analysis Plan

View Document

Related Links

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Other Identifiers

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U1111-1238-1869

Identifier Type: REGISTRY

Identifier Source: secondary_id

VAD00001

Identifier Type: -

Identifier Source: org_study_id

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