A Study to Learn About Group B Streptococcus Vaccine in Healthy Pregnant Women and Their Infants

Overview

Sponsor-declared trial summary

Key facts

Sponsor

Pfizer Inc.

Participant type

Pediatric, Healthy volunteers

Age range

In Utero, 0-17 years, 18-64 years

Gender

Male and Female

Therapeutic area

Diseases [C] - Bacterial Infections and Mycoses [C01]

Trial duration

23 Dec 2025 → ongoing

Decision date (initial)

2025-11-18

Transition trial

No

Low-intervention

No

Rare-disease indication

No

Vulnerable population

Yes

Trial design

CTIS Part I — objectives, methods, condition coding

Main objective

Scope: Safety, Others

- To describe the safety and tolerability of GBS6 in maternal participants
- To assess the safety of maternal immunization in infant participants born to pregnant individuals who were vaccinated with GBS6 during pregnancy
- To assess the ability of GBS6 to induce anti-CPS IgG antibody levels predicted to provide protection from invasive GBS late-onset disease (LOD) caused by the 6 individual vaccine serotypes (Ia, Ib, II III, IV, and V) in infants when GBS6 is administered to healthy pregnant women
- To assess the ability of GBS6 to induce anti-CPS IgG antibody levels predicted to provide protection from invasive GBS early-onset disease (EOD) caused by the 6 individual vaccine serotypes (Ia, Ib, II III, IV, and V) in infants when GBS6 is administered to healthy pregnant women
- To evaluate the aggregate predicted VE combining all 6 serotypes in GBS6 to provide protection from invasive GBS LOD based on serotype-specific anti-CPS IgG concentrations measured in infants at birth
- To evaluate the aggregate predicted VE combining all 6 serotypes in GBS6 to provide protection from invasive GBS EOD based on serotype-specific anti-CPS IgG concentrations measured in infants at birth

Secondary objectives 6

1. To describe anti-CPS IgG antibody levels predicted to provide protection from invasive GBS disease (all disease) caused by the 6 individual vaccine serotypes in infants when GBS6 is administered to healthy pregnant women
2. To describe anti-CPS IgG antibody levels in infant participants born to maternal participants vaccinated with GBS6
3. To assess the ability of GBS6 to induce opsonophagocytic activity (OPA) titers at birth in infant participants born to maternal participants vaccinated with GBS6
4. To describe anti-CPS IgG antibody levels predicted to provide protection from invasive GBS EOD and LOD, separately, caused by the 6 individual vaccine serotypes (Ia, Ib, II, III, IV, and V) in infants when GBS6 is administered to healthy pregnant women
5. To further describe the immunogenicity of GBS6 in maternal participants when administered to healthy pregnant women
6. To describe serum IgG responses to active immunization with diphtheria toxoid– containing vaccine and/or PCV in infant participants born to maternal participants vaccinated with GBS6 versus placebo

Conditions and MedDRA coding

Group B streptococcus (GBS) disease

Regulatory references

Scientific advice from competent authorities

Medicines And Healthcare Products Regulatory Agency, European Medicines Agency, Food And Drug Administration

EMA paediatric investigation plan (PIP)

EMEA-000025-PIP58-54

Plan to share IPD

Yes

IPD plan description

Pfizer will provide access to individual de-identified participant data and related study documents (e.g. protocol, Statistical Analysis Plan (SAP), Clinical Study Report (CSR)) upon request from qualified researchers, and subject to certain criteria, conditions, and exceptions. Further details on Pfizer's data sharing criteria and process for requesting access can be found at: https://www.pfizer.com/science/clinical_trials/trial_data_and_results/data_requests.

Eligibility criteria

Principal inclusion / exclusion criteria as submitted by sponsor

Inclusion criteria 3

1. Inclusion Criteria – Maternal Participants - Healthy pregnant women ≤49 years of age who are between 24 0/7 and 36 0/7 weeks of gestation on the day of planned vaccination, with an uncomplicated, singleton pregnancy, and who have no known increased risk of pregnancy complications
2. Inclusion Criteria – Maternal Participants - Had a fetal anomaly ultrasound examination performed at ≥18 weeks of gestation with no significant fetal abnormalities observed
3. Inclusion Criteria – Maternal Participants - Documented negative human immunodeficiency virus (HIV) antibody test, syphilis test, and hepatitis B virus (HBV) surface antigen test during this pregnancy and prior to randomization

Exclusion criteria 9

1. Exclusion Criteria – Maternal Participants - Prepregnancy body mass index (BMI) of >40 kg/m2. If a prepregnancy BMI is not available, the BMI at the time of the first obstetric visit during the current pregnancy must be used
2. Exclusion Criteria – Maternal Participants - Current pregnancy complications or abnormalities that may increase the risk associated with the participation in and completion of the study
3. Exclusion Criteria – Maternal Participants - Prior pregnancy complications or abnormalities that, based on the investigator’s judgment, may increase the risk associated with the participation in and completion of the study
4. Exclusion Criteria – Maternal Participants - History of microbiologically proven invasive disease caused by GBS in the current pregnancy (eg, isolation of GBS from a sterile site: blood, cerebrospinal fluid [CSF], or synovial fluid). This does not include asymptomatic bacteriuria or urinary tract infection (UTI) unless associated with a positive blood culture
5. Exclusion Criteria – Maternal Participants - A known or suspected infection during the current pregnancy that may increase the risk of complications in pregnancy (eg, active tuberculosis, syphilis, primary genital herpes simplex, malaria)
6. Exclusion Criteria – Maternal Participants - Congenital or acquired immunodeficiency disorder, rheumatologic disorder, or other illness requiring chronic treatment with known immunosuppressant medications, including monoclonal antibodies, within the year prior to enrollment
7. Exclusion Criteria – Maternal Participants - Receiving treatment with known systemic immunosuppressive therapy, including cytotoxic agents for cancer or an autoimmune disease, or radiotherapy, within 60 days before enrollment or planned receipt throughout the course of the study
8. Exclusion Criteria – Maternal Participants - Receipt or planned receipt of blood/plasma products or immunoglobulin, from 60 days before study intervention administration, or planned receipt through delivery, with 1 exception: Rho(D) immune globulin (eg, RhoGAM), which can be given at any time
9. Exclusion Criteria – Maternal Participants - Receipt of monoclonal antibodies within the year prior to enrollment or the use of systemic corticosteroids (≥20 mg/day of prednisone or equivalent) for ≥14 days within 28 days prior to study vaccination and/or during study participation

Endpoints

Primary and secondary outcome measures (English text)

Primary endpoints 6

1. Prespecified local reactions (redness, swelling, and pain at the injection site).
2. Prespecified systemic events (fever, nausea, vomiting, diarrhea, headache, fatigue, muscle pain, and joint pain).
3. Adverse events (AEs).
4. Serious adverse events (SAEs).
5. Medically attended adverse events (MAAEs).
6. GBS serotype specific anti-CPS IgG antibody concentrations measured at birth in infant participants

Secondary endpoints 5

1. GBS serotype-specific anti-CPS IgG antibody concentrations in infant participants
2. GBS serotype-specific OPA antibody titers in infant participants
3. GBS serotype-specific anti-CPS IgG antibody concentrations measured at birth in infant participants
4. GBS serotype-specific anti-CPS IgG antibody concentrations in maternal participants
5. Serum IgG concentration to diphtheria toxoid in a subset of infant participants. Serum IgG concentration to PCV serotypes in a subset of infant participants

Investigational products

Investigational medicinal products (IMPs), comparators, placebo, auxiliary

Test 1

Placebo 1

Sponsors and contacts

Sponsor organisations, regulatory contacts, third parties

Pfizer Inc.

Sponsor organisation

Pfizer Inc.

Address

235 East 42nd Street

City

New York

Postcode

10017-5703

Country

United States

Scientific contact point

Organisation

Pfizer Inc.

Contact name

Clinical Medical Lead

Public contact point

Organisation

Pfizer Inc.

Contact name

Clinical Medical Lead

Third parties 3

Locations

3 EU/EEA countries · 26 investigational sites

By country

Investigational sites

Country notifications

Trial-start, recruitment-start, end and early-termination notifications submitted per Member State

Results and documents

Annex IV summary of results, Annex V layperson summary, and all documents registered in CTIS for this trial

Documents 24 files

Public protocol annexes, IB summaries, regulatory submissions and post-authorisation documents registered in CTIS.

Application history

6 submissions — initial application plus substantial / non-substantial modifications