Clinical trial NCT06866405: A Phase 3 Study of Revaccination in Subsequent Pregnancies With Bivalent RSV Vaccine and Duration of Protection of a Single Dose
Official title: 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.
Study type: INTERVENTIONAL
Overall status: RECRUITING
Phase: PHASE3
Conditions: RSV Infection
Keywords: Pregnancy
RSV vaccine
RSV
Maternal immunization
Lead sponsor: Pfizer
Sponsor class: INDUSTRY
First posted: 2025-03-10
Enrollment: 550
Sex: ALL
Minimum age (years): 0
Standard ages: CHILD
ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: PREVENTION

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.

Detailed description: This study will include pregnant participants and their unborn babies (Cohort 1 and Cohort 2) and non-pregnant participants (Cohort 3), as described below:

* Cohort 1- Pregnant participants who had previously received RSVpreF as part of a Pfizer clinical trial and have antibody data available from that trial will get a second dose of RSVpreF.
* Cohort 2- Pregnant participants who received the RSVpreF in a previous pregnancy, either through commercial means with Abrysvo® or as part of a Pfizer clinical trial, will be randomly chosen to get either one dose of the RSVpreF or one dose of a placebo. This applies to those who do not have antibody data available from the earlier trial.

For both groups of pregnant participants, the study will look at how safe and well-tolerated the vaccine is during pregnancy, as well as how the body responds to it.

Infants will be monitored for six months after birth to check safety and antibodies level.

• Cohort 3- Nonpregnant participants who received RSVpreF during a previous pregnancy as part of an earlier clinical trial will have blood samples taken to see how well their immune response has persisted over time. Participants will not receive any vaccine.

Eligibility criteria: Pregnant Participants-Cohort 1 and Cohort 2 Key Inclusion Criteria

* 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.

Key Exclusion Criteria

* 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.

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.

Nonpregnant Participants-Cohort 3 Key Inclusion Criteria

* 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.

Key Exclusion Criteria

* 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.

Primary outcomes:
measure: Percentage of pregnant participants reporting local reactions
timeFrame: From Day 1 Through at least Day 7 after Vaccination
measure: Percentage of pregnant participants reporting systemic events
timeFrame: From Day 1 Through at least Day 7 after Vaccination
measure: Percentage of pregnant participants reporting adverse events
timeFrame: From Day 1 through 4 weeks after vaccination
measure: Percentage of pregnant participants reporting serious adverse events
timeFrame: From Day 1 throughout the study
measure: In infant participants born to pregnant participants receiving a second dose of the study intervention, the percentage of participants reporting adverse events.
timeFrame: From birth through 1 month of age
measure: 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.
timeFrame: From birth through 6 months of age.
measure: Proportion of participants achieving neutralizing antibody to RSV A and RSV B at birth
timeFrame: At birth
Secondary outcomes:
measure: Proportion of participants achieving neutralizing antibody to RSV A and RSV B at 3 months and 6 months
timeFrame: At 3 months and 6 months
Other outcomes:
Locations:
city: Panama City Beach
country: United States
facility: Emerald Coast Pediatrics
state: Florida
city: Panama City
country: United States
facility: Emerald Coast OBGYN Clinical Research
state: Florida
city: Panama City
country: United States
facility: Emerald Coast Pediatrics
state: Florida
city: Panama City
country: United States
facility: HCA Florida Gulf Coast Hospital
state: Florida
city: Boise
country: United States
facility: Advanced Specialty Research
state: Idaho
city: Boise
country: United States
facility: Saint Alphonsus Regional Medical Center
state: Idaho
city: Boise
country: United States
facility: St. Luke's Boise Medical Center
state: Idaho
city: Idaho Falls
country: United States
facility: Clinical Research Prime
state: Idaho
city: Nampa
country: United States
facility: Saint Alphonsus Medical Center
state: Idaho
city: Nampa
country: United States
facility: St. Luke's Nampa Medical Center
state: Idaho
city: Lafayette
country: United States
facility: Velocity Clinical Research, Lafayette
state: Louisiana
city: New Orleans
country: United States
facility: Velocity Clinical Research - New Orleans
state: Louisiana
city: Boston
country: United States
facility: Boston Medical Center
state: Massachusetts
city: Gulfport
country: United States
facility: Velocity Clinical Research, Gulfport
state: Mississippi
city: Great Falls
country: United States
facility: Boeson Research GTF
state: Montana
city: Great Falls
country: United States
facility: OBGYN Associates
state: Montana
city: Kalispell
country: United States
facility: Boeson Research KAL
state: Montana
city: Kalispell
country: United States
facility: Heart & Hands Midwifery
state: Montana
city: Missoula
country: United States
facility: Boeson Research MSO
state: Montana
city: Missoula
country: United States
facility: Origin Health
state: Montana
city: Grand Island
country: United States
facility: Velocity Clinical Research, Grand Island
state: Nebraska
city: Norfolk
country: United States
facility: Velocity Clinical Research, Norfolk
state: Nebraska
city: Albuquerque
country: United States
facility: Presbyterian Hospital
state: New Mexico
city: Albuquerque
country: United States
facility: UNM Hospital
state: New Mexico
city: Albuquerque
country: United States
facility: Velocity Clinical Research, Albuquerque
state: New Mexico
city: Albuquerque
country: United States
facility: Lovelace Women's Hospital
state: New Mexico
city: Houston
country: United States
facility: Memorial Hermann Memorial City Hospital
state: Texas
city: Houston
country: United States
facility: The University of Texas Health Science Center at Houston
state: Texas
city: Norfolk
country: United States
facility: Sentara Leigh Hospital
state: Virginia
city: Norfolk
country: United States
facility: The Group For Women - Kempsville Office
state: Virginia
city: Norfolk
country: United States
facility: Tidewater Physicians for Women
state: Virginia
city: Norfolk
country: United States
facility: WomensCare Center
state: Virginia
city: North Chesterfield
country: United States
facility: Virginia Physicians For Women (VPFW)
state: Virginia
city: Richmond
country: United States
facility: Clinical Research Partners, LLC
state: Virginia
city: Richmond
country: United States
facility: Infusion Solutions, LLC
state: Virginia
Study officials:
affiliation: Pfizer
name: Pfizer CT.gov Call Center
role: STUDY_DIRECTOR
References: