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

NCT04491877 | Completed Phase 1 Results FDA Drug

• 2 other identifiers: VAD00001U1111-1238-1869
• Study Type: interventional
• Target: 259
• Locations: 3 countries
• Sites: 29

Brief Summary

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.

Conditions

Respiratory Syncytial Virus Infection

Outcome Measures

Primary Outcomes (7)

• Number of Participants With Immediate Unsolicited Systemic Adverse Events (AEs)

  An AE is any untoward medical occurrence in a participant or in a clinical investigation participant administered a medicinal product and which does not necessarily have a causal relationship with this treatment. An unsolicited AE is an observed AE that does not fulfill the conditions pre-listed in the case report book (CRB) in terms of diagnosis and/or onset window post-vaccination. Systemic AEs are all AEs that were not injection or administration site reactions. Immediate events are recorded to capture medically relevant unsolicited systemic AEs (including those related to the product administered) that occur within the first 30 minutes after vaccination.

  Cohorts 1 and 3: Within 30 minutes after vaccination on Day 0; Cohorts 2 and 4: Within 30 minutes after vaccination on Days 0 and 56

• Number of Participants With Solicited Administration Site and Systemic Reactions

  All noxious and unintended responses to a medicinal product related to any dose are considered adverse reactions (AR). A solicited reaction is an "expected" AR (sign or symptom) observed and reported under the conditions (nature and onset) pre-listed in the protocol and CRB. An administration site reaction is an AR at and around the administration site. Systemic ARs are all ARs that are not injection or administration site reactions.

  Cohorts 1 and 3: Within 28 days after vaccination on Day 0; Cohorts 2 and 4: Within 28 days after vaccination on Days 0 and 56

• Number of Participants With Unsolicited Adverse Events

  An AE is any untoward medical occurrence in a participant or in a clinical investigation participant administered a medicinal product and which does not necessarily have a causal relationship with this treatment. An unsolicited AE is an observed AE that does not fulfill the conditions pre-listed in the CRB in terms of diagnosis and/or onset window post-vaccination.

  Cohorts 1 and 3: Within 28 days after vaccination on Day 0; Cohorts 2 and 4: Within 28 days after vaccination on Days 0 and 56

• Number of Participants With Adverse Events of Special Interest (AESIs)

  An AESI is one of scientific and medical concern specific to the Sponsor's product or program, for which ongoing monitoring and rapid communication by the investigator to the sponsor can be appropriate.

  Cohorts 1 and 3: Within 28 days after vaccination on Day 0; Cohorts 2 and 4: Within 28 days after vaccination on Days 0 and 56

• Number of Participants With Medically Attended Adverse Events (MAAEs)

  An MAAE is a new onset or a worsening of a condition that prompts the participant or participant's parent/guardian/legally authorized representative to seek unplanned medical advice at a physician's office or Emergency Department.

  Cohorts 1 and 3: Within 28 days after vaccination on Day 0; Cohorts 2 and 4: Within 28 days after vaccination on Days 0 and 56

• Number of Participants With Serious Adverse Events (SAEs)

  An SAE is any untoward medical occurrence that at any dose results in death or is life-threatening or requires inpatient hospitalization or prolongation of existing hospitalization or results in persistent or significant disability/incapacity or is a congenital anomaly/birth defect or is an important medical event.

  From the first study vaccine administration (Day 0) up to end of the study, maximum of 12 months

• Geometric Mean Titers Against RSV A Neutralizing Antibody in RSV-Naïve Participants

  RSV A neutralizing antibody measured by microneutralization. RSV-naïve participants are defined as undetectable serum anti-RSV A IgA antibodies.

  Cohorts 1 and 3: Day 56; Cohorts 2 and 4: Days 56 and 84

Secondary Outcomes (6)

• Titer of Vaccine Virus Shedding Measured by Reverse Transcription Polymerase Chain Reaction (RT-PCR)

  Cohorts 1 and 3: Day 7; Cohorts 2 and 4: Days 7 and 63

• Percentage of Participants Infected With Vaccine Virus at Days 56 and 84

  Cohorts 1 and 3: Day 56; Cohorts 2 and 4: Days 56 and 84

• Geometric Mean Titers Against RSV A Neutralizing Antibody in RSV-Experienced Participants

  Cohorts 1 and 3: Day 56; Cohorts 2 and 4: Days 56 and 84

• Geometric Mean Titers Against Serum Anti-F Immunoglobulin G (IgG) Antibody

  Cohorts 1 and 3: Day 56; Cohorts 2 and 4: Days 56 and 84

• Geometric Mean Titers Against RSV A Neutralizing Antibody After the RSV Surveillance Season

  Cohorts 1 and 3: Within 5 months after vaccination on Day 0; Cohorts 2 and 4: Within 5 months after vaccination on Day 56

Study Arms (9)

Cohort 1 (RSV vaccine formulation 1)

EXPERIMENTAL

1 administration of RSV vaccine formulation 1 on Day 0

Biological: RSV vaccine formulation 1

Cohort 1 (Placebo)

PLACEBO COMPARATOR

1 administration of placebo on Day 0

Biological: Placebo

Cohort 2 (RSV vaccine formulation 1)

EXPERIMENTAL

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

Biological: RSV vaccine formulation 1

Cohort 2 (Placebo)

PLACEBO COMPARATOR

2 administrations of placebo on Day 0 and Day 56

Biological: Placebo

Cohort 3 (RSV vaccine formulation 2)

EXPERIMENTAL

1 administration of RSV vaccine formulation 2 on Day 0

Biological: RSV vaccine formulation 2

Cohort 3 (Placebo)

PLACEBO COMPARATOR

1 administration of placebo on Day 0

Biological: Placebo

Cohort 4 (RSV vaccine formulation 1)

EXPERIMENTAL

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

Biological: RSV vaccine formulation 1

Cohort 4 (RSV vaccine formulation 2)

EXPERIMENTAL

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

Biological: RSV vaccine formulation 2

Cohort 4 (Placebo)

PLACEBO COMPARATOR

2 administrations of placebo on Day 0 and Day 56

Biological: Placebo

Interventions

RSV vaccine formulation 1 BIOLOGICAL

Pharmaceutical form: Suspension of virus Route of administration: Intranasal

Cohort 1 (RSV vaccine formulation 1); Cohort 2 (RSV vaccine formulation 1); Cohort 4 (RSV vaccine formulation 1)

RSV vaccine formulation 2 BIOLOGICAL

Pharmaceutical form: Suspension of virus Route of administration: Intranasal

Cohort 3 (RSV vaccine formulation 2); Cohort 4 (RSV vaccine formulation 2)

Placebo BIOLOGICAL

Pharmaceutical form: Suspension Route of administration: Intranasal

Cohort 1 (Placebo); Cohort 2 (Placebo); Cohort 3 (Placebo); Cohort 4 (Placebo)

Eligibility Criteria

• Age: 6 Months - 18 Months
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Child (0-17)

You may qualify if:

• 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

You may not qualify if:

• 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

Sponsors & Collaborators

• Sanofi Pasteur, a Sanofi Company: lead

Study Sites (29)

Matrix Clinical Research-Site Number:8400012

Gardena, California, 90247, United States

Location

Paradigm Clinical Research-Site Number:8400026

La Mesa, California, 91942, United States

Location

Matrix Clinical Research-Site Number:8400032

Los Angeles, California, 90057, United States

Location

California Research Foundation-Site Number:8400016

San Diego, California, 92123-1881, United States

Location

Elite Clinical Trials, Inc.-Site Number:8400001

Blackfoot, Idaho, 83221, United States

Location

Leavitt Clinical Research-Site Number:8400036

Idaho Falls, Idaho, 83404, United States

Location

Snake River Research-Site Number:8400022

Idaho Falls, Idaho, 83404, United States

Location

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

South Bend, Indiana, 46617, United States

Location

Alliance for Multispeciality Research-Site Number:8400014

El Dorado, Kansas, 67042, United States

Location

AMR - Newton-Site Number:8400002

Newton, Kansas, 67114, United States

Location

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

Lexington, Kentucky, 40517, United States

Location

Benchmark Research-Site Number:8400006

Covington, Louisiana, 70433, United States

Location

Nola Research Works-Site Number:8400017

New Orleans, Louisiana, 70125, United States

Location

Clinical Research Institute-Site Number:8400053

Minneapolis, Minnesota, 55402, United States

Location

Boeson Research-Site Number:8400011

Missoula, Montana, 59804, United States

Location

Be Well Clinical Studies-Site Number:8400054

Lincoln, Nebraska, 68516, United States

Location

Meridian Clinical Research - Norfolk-Site Number:8400005

Norfolk, Nebraska, 68701, United States

Location

MedPharmics Inc-Site Number:8400040

Albuquerque, New Mexico, 87102, United States

Location

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

Greenville, North Carolina, 27834, United States

Location

Coastal Pediatric Research-Site Number:8400031

Charleston, South Carolina, 29414, United States

Location

Tribe Clinical Research-Site Number:8400027

Greenville, South Carolina, 29607, United States

Location

FMC Science-Site Number:8400042

Lampasas, Texas, 76550-1820, United States

Location

JBR Clinical Research-Site Number:8400041

Salt Lake City, Utah, 84107, United States

Location

Pediatric Associates of Charlottesville North-Site Number:8400007

Charlottesville, Virginia, 22911, United States

Location

National Clinical Research Inc-Site Number:8400004

Richmond, Virginia, 23294, United States

Location

Investigational Site Number :1520001

Santiago, Reg Metropolitana de Santiago, 8380453, Chile

Location

Investigational Site Number :1520004

Santiago, Reg Metropolitana de Santiago, 8420383, Chile

Location

Investigational Site Number :3400001

San Pedro Sula, 21104, Honduras

Location

Investigational Site Number :3400002

Tegucigalpa, 11101, Honduras

Location

Related Publications (1)

• 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.

  PMID: 40856556 DERIVED

Related Links

• VAD00001 Plain Language Results Summary

MeSH Terms

Conditions

Respiratory Syncytial Virus Infections

Condition Hierarchy (Ancestors)

Pneumovirus Infections; Paramyxoviridae Infections; Mononegavirales Infections; RNA Virus Infections; Virus Diseases; Infections

Results Point of Contact

• Title: Trial Transparency Team
• Organization: Sanofi Pasteur

Contact-US@sanofi.com

800-633-1610

Study Officials

• Clinical Sciences & Operations

  Sanofi Pasteur, a Sanofi Company

  STUDY DIRECTOR

Publication Agreements

• PI is Sponsor Employee: No
• Restriction Type: OTHER
• Restrictive Agreement: Yes

Study Design

• Study Type: interventional
• Phase: phase 1
• Allocation: RANDOMIZED
• Masking: QUADRUPLE
• Who Masked: PARTICIPANT, CARE PROVIDER, INVESTIGATOR, OUTCOMES ASSESSOR
• Masking Details: 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.
• Purpose: PREVENTION
• Intervention Model: SEQUENTIAL
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: July 27, 2020
• First Posted: July 29, 2020
• Study Start: September 17, 2020
• Primary Completion: April 13, 2023
• Study Completion: April 13, 2023
• Last Updated: September 9, 2025
• Results First Posted: June 13, 2024

Record last verified: 2025-09

Data Sharing

• IPD Sharing: Will share

Locations

HO (2); CL (2); US (25)