NCT06866405|RecruitingPhase 3DMCFDA Drug

A Phase 3 Study of Revaccination in Subsequent Pregnancies With Bivalent RSV Vaccine and Duration of Protection of a Single Dose

A Phase 3 Study to Investigate the Safety, Tolerability, and Immunogenicity of Revaccinating Pregnant Participants During Subsequent Pregnancies and Persistence of Immunity of a Single Dose of a Bivalent Respiratory Syncytial Virus (RSV) Vaccine.

Pfizer ClinicalTrials.gov

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2 other identifiers

C3671059C3671059-OPENLABEL; Marguerite

Study Type

interventional

Target

550

Locations

4 countries

Sites

Timeline

RegisteredMar 2025

StartedApr 2025

CompletionFeb 2028

Brief Summary

This study aims to check how safe and well-tolerated a second dose of RSVpreF is when given during later pregnancies, and to see how long the immunity lasts from a single dose given during a previous pregnancy by examining the blood of nonpregnant participants who had the vaccine before.

Trial Health

On Track

Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Enrollment

550

participants targeted

Target at P75+ for phase_3

Timeline

22mo left

Started Apr 2025

Typical duration for phase_3

Geographic Reach

4 countries

94 active sites

Status

recruiting

Health score is calculated from publicly available data and should be used for screening purposes only.

Trial Relationships

Click on a node to explore related trials.

Study Timeline

Key milestones and dates

2.9 years study duration

Study Progress37%

Apr 2025Feb 2028

First Submitted

Initial submission to the registry

March 4, 2025

Completed

6 days until next milestone

First Posted

Study publicly available on registry

March 10, 2025

Completed

1 month until next milestone

Study Start

First participant enrolled

April 16, 2025

Completed

2.9 years until next milestone

Primary Completion

Last participant's last visit for primary outcome

February 24, 2028

Expected

Same day until next milestone

Study Completion

Last participant's last visit for all outcomes

February 24, 2028

Last Updated

May 5, 2026

Status Verified

May 1, 2026

Enrollment Period

2.9 years

First QC Date

March 4, 2025

Last Update Submit

May 4, 2026

Conditions

RSV Infection

Keywords

PregnancyRSV vaccineRSVMaternal immunization

Outcome Measures

Primary Outcomes (7)

Percentage of pregnant participants reporting local reactions
Pain at the injection site, redness, and swelling
From Day 1 Through at least Day 7 after Vaccination
Percentage of pregnant participants reporting systemic events
Fever, fatigue, headache, vomiting, nausea, diarrhea, muscle pain, and joint pain
From Day 1 Through at least Day 7 after Vaccination
Percentage of pregnant participants reporting adverse events
From Day 1 through 4 weeks after vaccination
Percentage of pregnant participants reporting serious adverse events
From Day 1 throughout the study
In infant participants born to pregnant participants receiving a second dose of the study intervention, the percentage of participants reporting adverse events.
From birth through 1 month of age
In infant participants born to pregnant participants receiving a second dose of the study intervention, the percentage of participants reporting serious adverse events and newly diagnosed medical conditions.
From birth through 6 months of age.
Proportion of participants achieving neutralizing antibody to RSV A and RSV B at birth
At birth

Secondary Outcomes (1)

Proportion of participants achieving neutralizing antibody to RSV A and RSV B at 3 months and 6 months
At 3 months and 6 months

Study Arms (2)

RSVpreF

EXPERIMENTAL

Biological: RSVpreF

Placebo

PLACEBO COMPARATOR

Biological: Placebo

Interventions

RSVpreFBIOLOGICAL

Single Dose

RSVpreF

PlaceboBIOLOGICAL

Single Dose

Placebo

Eligibility Criteria

Age0 Years+

Sexall

Healthy VolunteersYes

Age GroupsChild (0-17), Adult (18-64), Older Adult (65+)

You may qualify if:

Women aged 18 to 49 who are pregnant, between 24 and 36 weeks along, and expecting one baby without known risks for complications can participate.
Had the RSVpreF or Abrysvo vaccine during a previous pregnancy.
Had an ultrasound scan at 18 weeks or later during their current pregnancy, with no major fetal problems detected.
Based on their medical history, physical check-up, and the doctor's judgment, they are found suitable to join the study.
Agrees to let their baby take part in the study and gives their permission.
Able to sign a consent form, agreeing to follow the rules and conditions of the study.

You may not qualify if:

Received any approved or experimental RSV vaccine since their previous pregnancy.
Has a pre-pregnancy body mass index (BMI) over 40 kg/m2.
History of a severe bad reaction to a vaccine or a serious allergic reaction (like anaphylaxis) to any ingredient in the study vaccine or a similar vaccine.
Current pregnancy problems or issues at the time of giving consent.
Previous pregnancy issues or problems at the time of giving consent.
Women who are breastfeeding at the time of enrollment
Infant Participants
Proof that the parent(s) or legal guardian(s) has signed and dated a consent form.
Parent(s) or legal guardian(s) must agree to attend scheduled visits and follow the study plan, including laboratory tests and other procedures.
Have already received one dose of the RSVpreF vaccine during their previous pregnancy as part of the Pfizer clinical trial, and the results from that time can be used for this study.
Able to sign a consent form, agreeing to follow the rules and requirements of the study.
Received any approved or experimental RSV vaccine after participating in the Pfizer clinical trial.
Taking part in other studies with new drugs within 28 days before giving consent or during the study period.

Contact the study team to confirm eligibility.

Sponsors & Collaborators

Pfizerlead

Study Sites (94)

Center for Research in Women's Health

Birmingham, Alabama, 35233, United States

RECRUITING

Children's of Alabama

Birmingham, Alabama, 35233, United States

RECRUITING

University of Alabama at Birmingham - School of Medicine

Birmingham, Alabama, 35233, United States

RECRUITING

University of Alabama at Birmingham Women & Infants Center

Birmingham, Alabama, 35233, United States

RECRUITING

USA Health Children's and Women's Hospital

Mobile, Alabama, 36604, United States

RECRUITING

USA Health Strada Patient Care Center

Mobile, Alabama, 36604, United States

RECRUITING

Ronald Reagan UCLA Medical Center

Los Angeles, California, 90024, United States

RECRUITING

Ronald Reagan UCLA Medical Center (inpatient hospital)

Los Angeles, California, 90095, United States

RECRUITING

Ronald Reagan UCLA Medical Center

Los Angeles, California, 90095, United States

RECRUITING

UCLA (outpatient clinic)

Los Angeles, California, 90095, United States

RECRUITING

UCLA Clinical and Translational Research Center (research clinic)

Los Angeles, California, 90095, United States

RECRUITING

UCLA

Los Angeles, California, 90095, United States

RECRUITING

Lucile Packard Children's Hospital-Labor and Delivery Unit

Palo Alto, California, 94304, United States

RECRUITING

Stanford Obstetrics Clinic

Palo Alto, California, 94304, United States

RECRUITING

Stanford University Medical Center

Palo Alto, California, 94304, United States

RECRUITING

Stanford University

Palo Alto, California, 94304, United States

RECRUITING

Anschutz Health Sciences Building (AHSB)