A Study on the Immunogenicity and Safety of 3 Different Dose Concentrations of a Respiratory Syncytial Virus Vaccine in Infants and Toddlers

NCT06705140 | Terminated Phase 3 Results DMC FDA Drug

• 3 other identifiers: VAD000152023-509536-26U1111-1298-7338
• Study Type: interventional
• Target: 42
• Locations: 1 country
• Sites: 3

Brief Summary

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.

Conditions

Healthy Volunteers; RSV Immunisation

Keywords

RSV; RSVt (RSV toddler and Infant) Vaccine

Outcome Measures

Primary Outcomes (9)

• Cohort 2: Geometric Mean Titers (GMT) of RSV A Serum Neutralizing Antibodies at Day 85 (Post-Dose 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).

  Day 85 (28 days post-vaccination 2)

• Cohort 2: Geometric Mean Titers of RSV B Serum Neutralizing Antibodies at Day 85 (Post-Dose 2)

  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.

  Day 85 (28 days post-vaccination 2)

• Cohorts 1 and 2: Number of Participants With Immediate Unsolicited Systemic Adverse Events (AEs)

  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.

  Up to 30 minutes after each vaccination (post-dose on Day 1)

• Cohorts 1 and 2: Number of Participants With Solicited Administration Site Reactions

  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.

  Up to 21 days after each vaccination (post-dose on Day 1)

• Cohorts 1 and 2: 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 and considered as related to the study vaccine administered.

  Up to 21 days after each vaccination (post-dose on Day 1)

• Cohorts 1 and 2: Number of Participants With Unsolicited Adverse Events

  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.

  Up to 28 days after each vaccination (post-dose on Day 1)

• Cohorts 1 and 2: Number of Participants With Medically Attended Adverse Events (MAAEs)

  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.

  From first dose of study vaccine administration (Day 1) to 198 days

• Cohorts 1 and 2: Number of Participants With Serious Adverse Events (SAEs)

  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.

  From first dose of study vaccine administration (Day 1) to 198 days

• Cohorts 1 and 2: Number of Participants With Adverse Events of Special Interest (AESIs)

  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.

  From first dose of study vaccine administration (Day 1) to 198 days

Secondary Outcomes (5)

• Cohort 1: Geometric Mean Titers of RSV A and B Serum Neutralizing Antibodies at Baseline (Day 1) and Day 85

  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

  Baseline (Day 1) and Day 85

• Cohorts 1 and 2: Percentage of Participants With Quantified Shedding >=3.37 Lower Limit of Quantitation (LLOQ)

  Day 8 and Day 64

• Cohorts 1 and 2: Percentage of Participants With Detectable Shedding >=2.08 Limit of Detection

  Day 8 and Day 64

• Cohorts 1 and 2: Titer of Vaccine Virus Shedding in Participants Detected in Nasal Samples Quantified by Quantitative Real Time-Polymerase Chain Reaction

  Day 8 and Day 64

Study Arms (8)

Cohort 1: Group 1- (SD RSVt vaccine)

EXPERIMENTAL

Participants received 2 intranasal administrations of SD RSVt vaccine

Biological: Standard Dose (SD) RSVt vaccine

Cohort 1: Group 2-Control

PLACEBO COMPARATOR

Participants received 2 intranasal administrations of placebo

Biological: Placebo

Cohort 1: Group 3- (HD RSVt vaccine)

EXPERIMENTAL

Participants received 2 intranasal administrations of HD RSVt vaccine

Biological: High Dose (HD) RSVt vaccine

Cohort 1: Group 4-Control

PLACEBO COMPARATOR

Participants received 2 intranasal administrations of placebo

Biological: Placebo

Cohort 2: Group 1- (LD RSVt vaccine)

EXPERIMENTAL

Participants received 2 intranasal administrations of LD RSVt vaccine

Biological: Low Dose (LD) RSVt vaccine

Cohort 2: Group 2- (SD RSVt vaccine)

EXPERIMENTAL

Participants received 2 intranasal administrations of SD RSVt vaccine

Biological: Standard Dose (SD) RSVt vaccine

Cohort 2: Group 3- (HD RSVt vaccine

EXPERIMENTAL

Participants received 2 intranasal administrations of HD RSVt vaccine

Biological: High Dose (HD) RSVt vaccine

Cohort 2: Group 4-Control

PLACEBO COMPARATOR

Participants received 2 intranasal administrations of placebo

Biological: Placebo

Interventions

Placebo BIOLOGICAL

Pharmaceutical form:Liquid for nasal spray-Route of administration:Intranasal

Cohort 1: Group 2-Control; Cohort 1: Group 4-Control; Cohort 2: Group 4-Control

Low Dose (LD) RSVt vaccine BIOLOGICAL

Pharmaceutical form: Liquid for nasal spray Route of administration: Intranasal

Also known as: 534

Cohort 2: Group 1- (LD RSVt vaccine)

Standard Dose (SD) RSVt vaccine BIOLOGICAL

Pharmaceutical form:Liquid for nasal spray-Route of administration:Intranasal

Also known as: 534

Cohort 1: Group 1- (SD RSVt vaccine); Cohort 2: Group 2- (SD RSVt vaccine)

High Dose (HD) RSVt vaccine BIOLOGICAL

Pharmaceutical form:Liquid for nasal spray-Route of administration:Intranasal

Also known as: 534

Cohort 1: Group 3- (HD RSVt vaccine); Cohort 2: Group 3- (HD RSVt vaccine

Eligibility Criteria

• Age: 6 Months - 21 Months
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Child (0-17)

You may qualify if:

• 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).

You may not qualify if:

• 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:

Sponsors & Collaborators

• Sanofi Pasteur, a Sanofi Company: lead

Study Sites (3)

Investigational Site Number : 3400002

San Pedro Sula, Honduras

Location

Investigational Site Number : 3400001

Tegucigalpa, 11101, Honduras

Location

Investigational Site Number : 3400003

Tegucigalpa, 11101, Honduras

Location

MeSH Terms

Interventions

YM 534

Limitations and Caveats

The study was terminated early as per sponsor's decision (no safety concerns).

Results Point of Contact

• Title: Trial Transparency Team
• Organization: Sanofi Pasteur

Contact-US@sanofi.com

800-633-1610

Publication Agreements

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

Study Design

• Study Type: interventional
• Phase: phase 3
• Allocation: RANDOMIZED
• Masking: TRIPLE
• Who Masked: PARTICIPANT, INVESTIGATOR, OUTCOMES ASSESSOR
• Masking Details: * Blinding for vaccine group assignment: participants, parents or legally acceptable representatives (LARs), outcome assessors, investigators, laboratory personnel, Sponsor study staff * No blinding for study staff who prepare and administer the study interventions
• Purpose: PREVENTION
• Intervention Model: PARALLEL
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: November 22, 2024
• First Posted: November 26, 2024
• Study Start: November 25, 2024
• Primary Completion: June 11, 2025
• Study Completion: June 11, 2025
• Last Updated: August 3, 2026
• Results First Posted: August 3, 2026

Record last verified: 2026-07

Data Sharing

• IPD Sharing: Will share

Locations

HO (3)