Study to Learn About Safety, Tolerability, and Immune Response of a Catch-up Pneumococcal Vaccine in Children and Adolescents

A PHASE 3, RANDOMIZED DOUBLE-BLIND TRIAL TO EVALUATE THE SAFETY, TOLERABILITY, AND IMMUNOGENICITY OF A CATCH-UP VACCINATION REGIMEN OF A MULTIVALENT PNEUMOCOCCAL CONJUGATE VACCINE IN HEALTHY CHILDREN AND ADOLESCENTS

The purpose of this study is to learn about the safety of a new pneumococcal vaccine and how the new pneumococcal vaccine helps to fight against germs that can cause pneumonia (lung infections), meningitis (brain infections), and otitis media (ear infections) in children when compared to the pneumococcal vaccine that is currently in use, 20vPnC (Prevnar 20®).

This study will test if the new pneumococcal vaccine is as safe as the one that is currently in use. It will also assess how the new vaccine works in comparison to the one that is currently in use. To measure how the new pneumococcal vaccine compares to the current one, blood samples will be used to measure the body's ability to create proteins to fight those germs. This new vaccine can possibly provide additional protection against germs that cause pneumococcal disease that are not included in the vaccines that are currently given to children. Pneumococcal disease includes a variety of infections caused by a specific germ, Streptococcus pneumoniae

This study is seeking participants who:

• Are children aged 15 months to 18 years.
• May or may not have received any doses of pneumococcal conjugate vaccine (PCV) in the past.

The study will be conducted in the United States, Puerto Rico, and other countries.

Participants will be assigned to 1 of 3 groups based on age:

Group 1: 15 months to less than 2 years (about 300 participants) Group 2: 2 years to less than 5 years (about 300 participants) Group 3: 5 years to less than 18 years (about 600 participants)

Within each group, participants will be assigned by chance in a 2:1 ratio to receive 1 vaccine injection (shot) with either PG4 (new vaccine) or 20vPnC, given in the arm or thigh. This means that for every 3 participants, about 2 will receive PG4 and about 1 will receive 20vPnC.

Each participant will take part in the study for approximately 6 months. During this time, each participant will visit a clinic 2 times (visit 1 for vaccination and visit 2 to follow up) and will be contacted via telephone once (for a 6 month follow up).

At the study clinic visits, participants will have their blood drawn and be asked if they have experienced any side effects. A side effect is an unintentional or unexpected reaction to a vaccine. During the 6-month follow-up contact, participants will be asked about any further side effects.

Study Overview

• Status: Recruiting
• Conditions: Pneumococcal Disease
• Intervention / Treatment: Biological: 20-valent pneumococcal conjugate vaccine (20vPnC); Biological: PG4

• Study Type: Interventional
• Enrollment (Estimated): 1200
• Phase: Phase 3

Contacts and Locations

• Study Contact: Name: Pfizer CT.gov Call Center; Phone Number: 1-800-718-1021; Email: ClinicalTrials.gov_Inquiries@pfizer.com

Study Locations

• Puerto Rico
  • San Juan, Puerto Rico, 00907-1509
    • Not yet recruiting
    • BRCR Global Puerto Rico
• United States
  • Alabama
    • Birmingham, Alabama, United States, 35205
      • Not yet recruiting
      • Alabama Clinical Therapeutics, LLC Birmingham Pediatric Associates
  • California
    • Fair Oaks, California, United States, 95628
      • Not yet recruiting
      • Apex Research Group
    • Ontario, California, United States, 91762
      • Not yet recruiting
      • Orange County Research Institute
  • Florida
    • Hialeah, Florida, United States, 33012
      • Not yet recruiting
      • Indago Research & Health Center, Inc
    • Miami Lakes, Florida, United States, 33014
      • Not yet recruiting
      • Riveldi and Associates
  • Idaho
    • Ammon, Idaho, United States, 83406
      • Not yet recruiting
      • Medical Research Partners
    • Blackfoot, Idaho, United States, 83221
      • Not yet recruiting
      • Bingham Memorial Hospital
    • Boise, Idaho, United States, 83702
      • Not yet recruiting
      • ASR, LLC
  • Kentucky
    • Bardstown, Kentucky, United States, 40004
      • Not yet recruiting
      • Kentucky Pediatric/ Adult Research
  • Louisiana
    • Covington, Louisiana, United States, 70433
      • Not yet recruiting
      • Avacare
    • Lafayette, Louisiana, United States, 70508
      • Not yet recruiting
      • Velocity Clinical Research, Lafayette
    • Shreveport, Louisiana, United States, 71101
      • Not yet recruiting
      • LSU Health Shreveport Clinical Trials Office
    • Shreveport, Louisiana, United States, 71101
      • Not yet recruiting
      • Ochsner/LSU Health Shreveport - Progressive Pediatrics
    • Shreveport, Louisiana, United States, 71103
      • Not yet recruiting
      • Ochsner LSU Health Shreveport Ambulatory Care Center
    • Shreveport, Louisiana, United States, 71103
      • Not yet recruiting
      • Ochsner/LSU Health Shreveport Academic Medical Center
  • Michigan
    • Bingham Farms, Michigan, United States, 48025
      • Not yet recruiting
      • Michigan Center of Medical Research
  • Minnesota
    • Minneapolis, Minnesota, United States, 55402
      • Not yet recruiting
      • Clinical Research Institute, Inc.
  • Nebraska
    • Lincoln, Nebraska, United States, 68522
      • Not yet recruiting
      • Midwest Children's Health Research Institute
    • Lincoln, Nebraska, United States, 68516
      • Not yet recruiting
      • Midwest Children's Health Research Institute
    • Lincoln, Nebraska, United States, 68504
      • Not yet recruiting
      • Midwest Children's Health Research Institute
    • Lincoln, Nebraska, United States, 68505
      • Not yet recruiting
      • Midwest Children's Health Research Institute
  • New York
    • East Syracuse, New York, United States, 13057
      • Not yet recruiting
      • Child Health Care Associates
    • Horseheads, New York, United States, 14845
      • Not yet recruiting
      • Corning Center for Clinical Research
  • Ohio
    • Cincinnati, Ohio, United States, 45245
      • Not yet recruiting
      • Pediatric Associates of Mt. Carmel
    • Dayton, Ohio, United States, 45409
      • Not yet recruiting
      • Dayton Clinical Research
    • South Euclid, Ohio, United States, 44121
      • Recruiting
      • Senders Pediatrics
  • South Carolina
    • Simpsonville, South Carolina, United States, 29681
      • Recruiting
      • Tribe Clinical Research LLC. at Parkside Pediatrics Five Forks
  • Tennessee
    • Tullahoma, Tennessee, United States, 37388
      • Not yet recruiting
      • Pediatric Clinical Trials of Tennessee, LLC
  • Texas
    • Houston, Texas, United States, 77065
      • Not yet recruiting
      • Kool Kids Pediatrics
    • Houston, Texas, United States, 77054
      • Not yet recruiting
      • Mercury Clinical Research (Administrative Office)
    • Houston, Texas, United States, 77087
      • Not yet recruiting
      • Mercury Clinical Research - Pediatric Associates
    • Houston, Texas, United States, 77402
      • Not yet recruiting
      • Neutra Life Sciences
    • Richmond, Texas, United States, 77469
      • Not yet recruiting
      • Pediatric Center- Neutra Life Sciences
    • San Antonio, Texas, United States, 78215
      • Not yet recruiting
      • Sun Research Institute
    • Victoria, Texas, United States, 77901
      • Not yet recruiting
      • Victoria Clinical Research Group
  • Utah
    • Layton, Utah, United States, 84041
      • Not yet recruiting
      • Tanner Clinic
    • Layton, Utah, United States, 84041
      • Not yet recruiting
      • Tanner Clinic - Layton Parkway
    • Provo, Utah, United States, 84604
      • Not yet recruiting
      • AMR Clinical
    • Syracuse, Utah, United States, 84075
      • Not yet recruiting
      • AMR Clinical
    • West Jordan, Utah, United States, 84088
      • Not yet recruiting
      • Velocity Clinical Research, Salt Lake City
  • Virginia
    • Charlottesville, Virginia, United States, 22902
      • Not yet recruiting
      • Pediatric Research of Charlottesville, LLC
    • Richmond, Virginia, United States, 23226
      • Recruiting
      • Clinical Research Partners, LLC

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

Cohort 1 (Participants ≥15 Months to <2 Years of Age) Healthy toddlers and children ≥15 months to <2 years of age with documentation of prior receipt of PCV.

Cohort 2 (Participants ≥2 Years to <5 Years of Age) Healthy toddlers and children ≥2 years to <5 years of age with documentation of prior receipt of PCV if applicable.

Cohort 3 (Participants ≥5 Years to <18 Years of Age) Healthy children ≥5 years to <18 years of age with documentation of prior receipt of PCV (if applicable). A negative urine pregnancy test is required for individuals of childbearing potential (IOCBP). IOCBP or participants able to father must also agree to use a highly effective method of birth control.

Exclusion Criteria:

All Cohorts (Participants ≥15 Months to <18 Years of Age)

Children with significant medical, psychiatric, or neurological conditions (eg, immunodeficiency or history of seizure); or a history of confirmed invasive pneumococcal infection in the past will be excluded from enrolment in the trial

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Triple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: 20-valent pneumococcal conjugate vaccine (20vPnC) (intramuscular); 20-valent pneumococcal conjugate vaccine (20vPnC)	Biological: 20-valent pneumococcal conjugate vaccine (20vPnC); 20-valent pneumococcal conjugate vaccine (20vPnC); Other Names: Prevnar 20
Experimental: PG4 (intramuscular); Multivalent Pneumococcal vaccine	Biological: PG4; Multivalent Pneumococcal Vaccine

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Percentage of Participants With Local Reactions Within 7 Days After Vaccination	Within 7 days after Vaccination
Percentage of Participants With Systemic Events Within 7 Days after Vaccination	Within 7 days after Vaccination
Percentage of Participants With Adverse Events (AEs)	From Vaccination to 1 month after Vaccination
Percentage of Participants With Serious Adverse Events (SAEs)	From Vaccination to 6 months after Vaccination
GMCs of serotype-specific IgG concentrations	1 month after vaccination
GMTs of serotype-specific OPA titers	1 month after vaccination

Secondary Outcome Measures

Outcome Measure	Time Frame
Percentage of participants with predefined serotype-specific IgG concentrations	1 month after vaccination
IgG GMFRs	1 month after vaccination
Percentage of participants with a ≥4-fold rise in serotype-specific OPA titers	before to 1 month after vaccination
OPA GMFRs	before to 1 month after vaccination

Collaborators and Investigators

• Sponsor: Pfizer
• Investigators: Study Director: Pfizer CT.gov Call Center, Pfizer

Publications and helpful links

Helpful Links

• To obtain contact information for a study center near you, click here.

Study record dates

Study Major Dates

• Study Start (Estimated): June 17, 2026
• Primary Completion (Estimated): December 4, 2027
• Study Completion (Estimated): December 4, 2027

Study Registration Dates

• First Submitted: June 15, 2026
• First Submitted That Met QC Criteria: June 15, 2026
• First Posted (Actual): June 22, 2026

Study Record Updates

• Last Update Posted (Actual): June 22, 2026
• Last Update Submitted That Met QC Criteria: June 15, 2026
• Last Verified: June 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Infections; Gram-Positive Bacterial Infections; Bacterial Infections; Bacterial Infections and Mycoses; Streptococcal Infections; Pneumococcal Infections
• Other Study ID Numbers: C4931004; 2025-523445-10-00 (Registry Identifier: CTIS (EU))

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (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.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: Yes