Study on a Live-attenuated Respiratory Syncytial Virus Vaccine for Assessment of Safety, Transmissibility, and Genetic Stability of the Vaccine Virus Among Close Contacts in Infants and Toddlers 6 to < 24 Months of Age in Puerto Rico (USA)

NCT05687279 | Completed Phase 1 Results FDA Drug

• 2 other identifiers: VAD00014U1111-1278-3910
• Study Type: interventional
• Target: 80
• Locations: 2 countries
• Sites: 6

Brief Summary

The primary purpose of the study is to assess the shedding, transmission, and genetic stability of the live-attenuated RSVt vaccine after each intranasal vaccination (56 days apart) in infants and toddlers 6 to \< 24 months of age.

Conditions

Respiratory Syncytial Virus Infection

Outcome Measures

Primary Outcomes (3)

• Percentage of Placebo Receiving Pediatric Participants With Vaccine Virus Detected in Nasal Swabs After the First Vaccination

  Nasal swabs were collected to assess the presence of vaccine virus after first vaccination. Vaccine virus transmission was defined as presence of detected vaccine virus confirmed by RSVt quantitative reverse transcription polymerase chain reaction (qRT-PCR) assay (vaccine virus shedding \>=lower limit of detection \[LOD=2.80 log10 copies/mL\]) in pediatric participants receiving placebo. Percentages are rounded off to the tenth decimal place.

  Pre-vaccination on Day 1 and post-vaccination on Days 4, 8, 11, 15, 18 and 22

• Titer of Vaccine Virus Shedding in All Pediatric Participants Detected in Nasal Swabs

  Nasal swabs were collected to assess the shedding of the attenuated RSV vaccine strain and quantified by RSVt qRT PCR assay. Quantified virus shedding was defined as vaccine virus shedding \>=lower limit of quantification (LLOQ=3.37 log10 copies/mL).

  Pre-vaccination on Day 1 and post-vaccination on Days 4, 8, 11, 15, 18, 22, 64 and 71

• Percentage of Placebo Receiving Pediatric Participants With Detected Shedding Who Showed Any Genetic Sequence Variation After Each Vaccination

  Nasal swabs were collected to identify the difference in genetic sequence of mutated vaccine virus segments compared to the reference strain vaccine virus isolates in the vaccine virus positive swabs from pediatric participants receiving placebo after each vaccination. Detected virus shedding was defined as vaccine virus shedding \>=LOD (2.80 log10 copies/mL).

  Up to 21 days after each vaccination (Day 1 to Day 22 and Day 57 to Day 78)

Secondary Outcomes (5)

• Geometric Mean Titers (GMTs) of RSV A Serum Neutralizing Antibody (nAb) Titers

  Pre-vaccination on Day 1 (first vaccination) and Day 57 (second vaccination) and up to 28 days after second vaccination, Day 85

• Secondary: Geometric Mean Titers of RSV Serum Anti-F Immunoglobulin G (IgG) Enzyme-linked Immuno-adsorbant Assay (ELISA) Antibody

  Pre-vaccination on Day 1 (first vaccination) and Day 57 (second vaccination) and up to 28 days after second vaccination, Day 85

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

  Up to 30 minutes after each vaccination (Days 1 and 57)

• Number of Participants With Solicited Administration Site Reactions and Systemic Reactions

  Up to 21 days after each vaccination (Day 1 to Day 22 and Day 57 to Day 78)

• Number of Participants With Unsolicited Adverse Events

  Up to 28 days after each vaccination (Day 1 to Day 29 and Day 57 to Day 85)

Study Arms (2)

RSVt Vaccine Group

EXPERIMENTAL

2 intranasal administrations (56 days apart) of the RSVt vaccine at D01 and D57

Biological: RSVt Vaccine

Control Group

PLACEBO COMPARATOR

2 intranasal administrations (56 days apart) of the placebo at D01 and D57

Other: Control Group

Interventions

RSVt Vaccine BIOLOGICAL

Pharmaceutical Form: Suspension of virus in a nasal spray Route of Administration: Intranasal

RSVt Vaccine Group

Control Group OTHER

Pharmaceutical Form: Suspension of virus in a nasal spray Route of Administration: Intranasal

Control Group

Eligibility Criteria

• Age: 6 Months - 23 Months
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Child (0-17)

You may qualify if:

• Participants who are healthy as determined by medical evaluation including medical history.
• Born at full term of pregnancy (≥ 37 weeks) or born after a gestation period of 27 through 36 weeks 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
• Attends a daycare facility at least 3 days per week and 4 hours per day at which the participant would be in a contact group/playroom of at least one other child 6 to \< 24 months of age who will participate in this study or is a member of a household, which includes at least one other child 6 to \< 24 months of age who will participate in this study

You may not qualify if:

• 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
• 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 COVID-19 at the time of enrollment
• 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
• Member of a household that includes, or will include, an infant who is less than 6 months of age at the time of enrollment
• Attends a daycare facility and shares a daycare room with infants less than 6 months of age, and parent/legally acceptable representative is unable or unwilling to suspend attendance at the daycare facility for 28 days following study intervention administration
• Any need of supplemental oxygen therapy in a home or hospital setting at the time of enrollment.
• Participant's mother previous receipt or planned administration of an investigational RSV vaccine or any monoclonal antibody (such as Infliximab) during pregnancy and/or breastfeeding.
• Receipt or planned receipt of any of the following vaccines prior to or after the first study intervention administration:

Sponsors & Collaborators

• Sanofi Pasteur, a Sanofi Company: lead

Study Sites (6)

Meridian Clinical Research Norfolk Site Number : 8400003

Norfolk, Nebraska, 68701, United States

Location

Velocity Clinical Research, Omaha Site Number : 8400001

Omaha, Nebraska, 68134, United States

Location

Investigational Site Number : 6300004

Bayamón, 00960, Puerto Rico

Location

Investigational Site Number : 6300002

Carolina, 984, Puerto Rico

Location

Investigational Site Number : 6300003

Guayama, 00784, Puerto Rico

Location

Investigational Site Number : 6300001

San Juan, 00918, Puerto Rico

Location

MeSH Terms

Conditions

Respiratory Syncytial Virus Infections

Interventions

Control Groups

Condition Hierarchy (Ancestors)

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

Intervention Hierarchy (Ancestors)

Epidemiologic Research Design; Epidemiologic Methods; Investigative Techniques; Research Design; Methods

Results Point of Contact

• Title: Trial Transparency Team
• Organization: Sanofi

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: Observer-blind: * Blinding for vaccine group assignment: participants, parents or legally acceptable representative (LAR), 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: January 6, 2023
• First Posted: January 18, 2023
• Study Start: February 6, 2023
• Primary Completion: December 27, 2024
• Study Completion: December 27, 2024
• Last Updated: January 26, 2026
• Results First Posted: January 26, 2026

Record last verified: 2026-01

Data Sharing

• IPD Sharing: Will share

Locations

PR (4); US (2)