A Study to Learn About How a New Pneumococcal Vaccine Works in Infants.

A PHASE 3, RANDOMIZED, DOUBLE-BLIND TRIAL TO EVALUATE THE SAFETY, TOLERABILITY, AND IMMUNOGENICITY OF A MULTIVALENT PNEUMOCOCCAL CONJUGATE VACCINE IN HEALTHY INFANTS

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 infants 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 when given with other childhood vaccines.

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 infants. Pneumococcal disease includes a variety of infections caused by a specific germ, Streptococcus pneumoniae.

There are three groups in this study. All participants will be assigned to one of the three groups. This study is seeking participants who are:

• infants who are 2 months of age in Group 1;
• infants who are 2 to 6 months of age in Groups 2 and 3; and
• said to be healthy by the study doctor

About 3000 infants will be assigned to Group 1. The infants in this group will have a 1 in 2 chance (50%) of receiving either PG4 (new vaccine) or 20vPnC (currently in use) into the left thigh muscle at 2, 4, 6, and 12 to 15 months of age.

About 140 infants from outside the United States will be assigned to Group 2. The infants in this group will have a 1 in 2 chance (50%) of receiving either PG4 or 20vPnC into the left thigh muscle at 2 to 6, 3 to 8, 4 to 10, and 12 to 15 months of age.

About 90 infants from outside the United States will be assigned to Group 3. The infants in Group 3 will have a 1 in 3 chance (33%) of receiving either PG4 into the left thigh muscle, PG4 under the skin of the left thigh, or 20vPnC into the left thigh muscle at 2 to 6, 3 to 8, 4 to 10, and 12 to 15 months of age.

Infants in Group 1 will take part in this study for about 16 to 19 months (about 1 and a half years). Infants in Groups 2 and 3 will take part in this study for 12 to 21 months (about 1 to 1 and a half years). During this time, infants will have 6 study clinic visits and 1 phone call. At these study clinic visits, parent(s)/legal guardian(s) will be asked if the infant experienced any side effects. A side effect is an unintentional or unexpected reaction to a vaccine. Infants will have 3 blood samples collected.

Study Overview

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

• Study Type: Interventional
• Enrollment (Estimated): 3230
• 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

• Japan
  • Fukui, Japan, 910-0833
    • Not yet recruiting
    • Fukui Aiiku Hospital
  • Osaka, Japan, 544-0033
    • Not yet recruiting
    • Kubota Children's Clinic
  • Fukuoka
    • Fukuoka, Fukuoka, Japan, 814-0121
      • Not yet recruiting
      • Shindo children's clinic
    • Kasuga, Fukuoka, Japan, 816-0801
      • Not yet recruiting
      • Yokoyama Children'S Clinic
  • Hokkaido
    • Sapporo, Hokkaido, Japan, 062-0907
      • Not yet recruiting
      • Ohigesenseino Kodomo Clinic
  • Tokyo
    • Shinjuku-ku, Tokyo, Japan, 160-0017
      • Not yet recruiting
      • Futaba Clinic
  • Yamanashi
    • Kofu, Yamanashi, Japan, 400-0853
      • Not yet recruiting
      • Kose Children Clinic
• Puerto Rico
  • Bayamón, Puerto Rico, 00960
    • Not yet recruiting
    • Clinical Research Investigator Group
  • Caguas, Puerto Rico, 00726
    • Not yet recruiting
    • San Juan Bautista School of Medicine - Clinical Research Unit
  • Caguas, Puerto Rico, 00725
    • Not yet recruiting
    • Caguas Clinical Research
  • Guayama, Puerto Rico, 00784
    • Not yet recruiting
    • Clinical Research Puerto Rico
  • Ponce, Puerto Rico, 00716
    • Not yet recruiting
    • Ponce Medical School Foundation Inc./ CAIMED Center
  • Ponce, Puerto Rico, 00717
    • Not yet recruiting
    • BRCR Global Puerto Rico
  • San Juan, Puerto Rico, 00907
    • Not yet recruiting
    • BRCR Global Puerto Rico
  • Trujillo Alto, Puerto Rico, 00976-3910
    • Recruiting
    • San Miguel Medical
• United States
  • Alabama
    • Birmingham, Alabama, United States, 35205
      • Recruiting
      • Alabama Clinical Therapeutics, LLC Birmingham Pediatric Associates
  • Arkansas
    • Fayetteville, Arkansas, United States, 72703
      • Not yet recruiting
      • Northwest Arkansas Pediatric Clinic
    • Jonesboro, Arkansas, United States, 72401
      • Not yet recruiting
      • The Children's Clinic of Jonesboro, P.A.
  • California
    • Arcadia, California, United States, 91007
      • Not yet recruiting
      • San Gabriel Woman's Health
    • El Monte, California, United States, 91731
      • Not yet recruiting
      • Family Medical Clinic
    • Fresno, California, United States, 93704
      • Recruiting
      • Clinical Research of Central California
    • Montebello, California, United States, 90640
      • Not yet recruiting
      • SeraCollection Research Services, LLC
    • Palo Alto, California, United States, 94304
      • Not yet recruiting
      • Stanford University Medical Center CTRU - 800 Welch Road
  • Florida
    • Homestead, Florida, United States, 33030
      • Recruiting
      • C & R Research Services USA
    • Miami, Florida, United States, 33143
      • Recruiting
      • Florida Pharmaceutical Research and Associates, Inc.
    • Miami, Florida, United States, 33155
      • Not yet recruiting
      • Bioresearch Partner
    • Miami, Florida, United States, 33155
      • Not yet recruiting
      • Gold Coast Health Research Center, LLC
    • Miami, Florida, United States, 33173
      • Not yet recruiting
      • Dade Research Center
    • Miami, Florida, United States, 33183
      • Not yet recruiting
      • Vasconcello-Cohen MD Research, LLC.
    • Miami Lakes, Florida, United States, 33014
      • Not yet recruiting
      • Riveldi and Associates
    • North Lauderdale, Florida, United States, 33068
      • Recruiting
      • Eminent Clinical Research and Associates
    • Sweetwater, Florida, United States, 33182
      • Not yet recruiting
      • Cordova Research Institute LLC
  • Georgia
    • Norcross, Georgia, United States, 30093
      • Recruiting
      • Altruistic Clinical Research Global
  • Idaho
    • Ammon, Idaho, United States, 83406
      • Not yet recruiting
      • Medical Research Partners
    • Boise, Idaho, United States, 83702
      • Not yet recruiting
      • ASR, LLC
  • Illinois
    • Moline, Illinois, United States, 61265
      • Not yet recruiting
      • MidValley Research, Inc
  • Iowa
    • Ankeny, Iowa, United States, 50023
      • Not yet recruiting
      • The Iowa Clinic.
    • West Des Moines, Iowa, United States, 50265
      • Not yet recruiting
      • Eximia Research - IA, LLC (dba Integrated Clinical Trial Services, LLC)
  • Kansas
    • Derby, Kansas, United States, 67037
      • Not yet recruiting
      • Integrity Clinical Network, LLC
  • Louisiana
    • Haughton, Louisiana, United States, 71037
      • Recruiting
      • ACC Pediatric Research
  • Maryland
    • Columbia, Maryland, United States, 21045
      • Not yet recruiting
      • Kur Research, LLC
  • Michigan
    • Allen Park, Michigan, United States, 48101
      • Not yet recruiting
      • Michigan Institute of Research
    • Bingham Farms, Michigan, United States, 48025
      • Not yet recruiting
      • Michigan Center of Medical Research
  • Nebraska
    • Grand Island, Nebraska, United States, 68803
      • Not yet recruiting
      • Velocity Clinical Research, Grand Island
    • Lincoln, Nebraska, United States, 68516
      • Recruiting
      • Midwest Children's Health Research Institute
    • Lincoln, Nebraska, United States, 68522
      • 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
    • Rochester, New York, United States, 14642
      • Not yet recruiting
      • University of Rochester Medical Center
  • North Carolina
    • Durham, North Carolina, United States, 27703
      • Recruiting
      • Duke Vaccine and Trials Unit
    • Durham, North Carolina, United States, 27704
      • Recruiting
      • Durham Pediatrics at North Duke Street
    • Wilmington, North Carolina, United States, 28405
      • Not yet recruiting
      • Wilmington Health
  • Ohio
    • Cincinnati, Ohio, United States, 45245
      • Not yet recruiting
      • Pediatric Associates of Mt. Carmel
    • Dayton, Ohio, United States, 45429
      • Not yet recruiting
      • PriMED Clinical Research
    • South Euclid, Ohio, United States, 44121
      • Recruiting
      • Senders Pediatrics
  • Pennsylvania
    • Erie, Pennsylvania, United States, 16506
      • Not yet recruiting
      • Allegheny Health and Wellness Pavilion
  • South Carolina
    • Simpsonville, South Carolina, United States, 29680
      • Recruiting
      • Tribe Clinical Research LLC. at Parkside Pediatrics Harrison Bridge Road
  • Tennessee
    • Tullahoma, Tennessee, United States, 37388
      • Not yet recruiting
      • Pediatric Clinical Trials of Tennessee, LLC
  • Texas
    • Brownsville, Texas, United States, 78520
      • Not yet recruiting
      • Proactive RGV
    • Edinburg, Texas, United States, 78539
      • Not yet recruiting
      • Proactive Clinical Research LLC
    • El Paso, Texas, United States, 79902
      • Not yet recruiting
      • Proactive El Paso,LLC
    • Houston, Texas, United States, 77065
      • Not yet recruiting
      • Kool Kids Pediatrics
    • Houston, Texas, United States, 77090
      • Not yet recruiting
      • Houston Clinical Research Associates
    • Houston, Texas, United States, 77087
      • Recruiting
      • Mercury Clinical Research - Pediatric Associates
    • Houston, Texas, United States, 77042
      • Not yet recruiting
      • Neutra Life Sciences
    • Houston, Texas, United States, 77054
      • Recruiting
      • Mercury Clinical Research (Administrative Office)
    • Houston, Texas, United States, 77077
      • Recruiting
      • Mercury Clinical Research - Sunrise Pediatrics
    • Mesquite, Texas, United States, 75149
      • Recruiting
      • SMS Clinical Research LLC
    • Richmond, Texas, United States, 77469
      • Not yet recruiting
      • Pediatric Center- Neutra Life Sciences
  • Utah
    • Provo, Utah, United States, 84604
      • Not yet recruiting
      • AMR Clinical
    • Syracuse, Utah, United States, 84075
      • Not yet recruiting
      • AMR Clinical
  • Virginia
    • Richmond, Virginia, United States, 23226
      • Recruiting
      • Clinical Research Partners, LLC
    • Richmond, Virginia, United States, 23233
      • Not yet recruiting
      • Tekton Research, LLC.

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• infants who are 2 months of age in Group 1.
• infants who are 2 to 6 months of age in Groups 2 and 3.
• Healthy infants determined by clinical assessment, including medical history and clinical judgment, to be eligible for the study.

Exclusion Criteria:

• History of severe adverse reaction associated with a vaccine and/or severe allergic reaction (eg, anaphylaxis).
• Major known congenital malformation or serious chronic disorder.
• Other acute or chronic medical or psychiatric condition or laboratory abnormality that may increase the risk associated with study participation or investigational product administration or may interfere with the interpretation of study results and, in the judgment of the investigator, would make the participant inappropriate for entry into this study.
• Previous vaccination with any licensed or investigational pneumococcal vaccine, or planned receipt through study participation.

Study Plan

How is the study designed?

Design Details

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

Number of Arms

7

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Group 1 PG4 (intramuscular); Multivalent Pneumococcal Vaccine	Biological: PG4; Multivalent Pneumococcal Vaccine
Active Comparator: Group 1 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: Group 2 PG4 (intramuscular); Multivalent Pneumococcal Vaccine	Biological: PG4; Multivalent Pneumococcal Vaccine
Active Comparator: Group 2 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: Group 3 PG4 (intramuscular); Multivalent Pneumococcal Vaccine	Biological: PG4; Multivalent Pneumococcal Vaccine
Experimental: Group 3 PG4 (subcutaneous); Multivalent Pneumococcal Vaccine	Biological: PG4; Multivalent Pneumococcal Vaccine
Active Comparator: Group 3 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

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Percentage of participants reporting local reactions within 7 days after each dose	Prompted local reactions after each dose	Day 7
Percentage of participants reporting serious adverse events (SAEs)	SAEs occurring from Dose 1 to 6 months after Dose 4	Dose 1 to 6 months after Dose 4
Percentage of participants reporting systemic events within 7 days after each dose	Prompted systemic events after each dose	Day 7
Percentage of participants reporting adverse events (AEs) from Dose 1 to 1 month after Dose 3	AEs occurring from Dose 1 to 1 month after Dose 3	Dose 1 to 1 month after Dose 3
Percentage of participants reporting AEs from Dose 4 to 1 month after Dose 4	AEs occurring from Dose 4 to 1 month after Dose 4	Dose 4 to 1 month after Dose 4
Differences in percentages of participants with predefined pneumococcal specific immunoglobulin G (IgG) concentrations 1 month after Dose 3	Differences in pneumococcal immunoglobulin G (IgG) concentrations 1 month after Dose 3	1 month after Dose 3
Pneumococcal IgG geometric mean concentrations (GMCs) 1 month after Dose 4	Pneumococcal IgG GMCs 1 month after Dose 4	1 month after Dose 4

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Pneumococcal IgG GMCs 1 month after Dose 3	Pneumococcal IgG GMCs 1 month after Dose 3	1 month after Dose 3
Percentage of participants with serotype 3 specific predefined pneumococcal IgG concentrations 1 month after Dose 3	Pneumococcal serotype 3 IgG concentrations 1 month after Dose 3	1 month after Dose 3
Pneumococcal serotype 3 IgG GMCs 1 month after Dose 4	Pneumococcal serotype 3 IgG GMCs 1 month after Dose 4	1 month after Dose 4
Differences in percentages of participants with predefined pneumococcal serotype 6C and 15C immunoglobulin G (IgG) concentrations 1 month after Dose 3	Differences in pneumococcal serotype 6C and 15C immunoglobulin G (IgG) concentrations 1 month after Dose 3	1 month after Dose 3
Pneumococcal serotype 6C and 15C IgG GMCs and GMRs 1 month after Dose 4	Pneumococcal serotype 6C and 15C IgG GMCs and GMRs 1 month after Dose 4	1 month after Dose 4
Pneumococcal opsonophagocytic activity (OPA) titers 1 month after Dose 3	Pneumococcal OPA titers 1 month after Dose 3	1 month after Dose 3
Pneumococcal OPA titers prior to Dose 4	Pneumococcal OPA titers prior to Dose 4	Prior to Dose 4
Pneumococcal OPA titers 1 month after Dose 4	Pneumococcal OPA titers 1 month after Dose 4	1 month after Dose 4
Percentage of participants with predefined pneumococcal specific IgG concentrations 1 month after Dose 4	Percentage of participants with predefined pneumococcal specific IgG concentrations 1 month after Dose 4	1 month after Dose 4
Pneumococcal IgG concentrations 1 month after Dose 3	Pneumococcal IgG concentrations 1 month after Dose 3	1 month after Dose 3
Pneumococcal IgG concentrations prior to Dose 4	Pneumococcal IgG concentrations prior to Dose 4	Prior to Dose 4
Pneumococcal IgG concentrations 1 month after Dose 4	Pneumococcal IgG concentrations 1 month after Dose 4	1 month after Dose 4
IgG geometric mean fold rise (GMFR) from before Dose 4 to 1 month after Dose 4	IgG GMFR from before Dose 4 to 1 month after Dose 4	Before Dose 4 to 1 month after Dose 4
IgG GMFR from 1 month after Dose 3 to 1 month after Dose 4	IgG GMFR from 1 month after Dose 3 to 1 month after Dose 4	From 1 month after Dose 3 to 1 month after Dose 4
Percentages of participants with prespecified antibody levels to specific concomitant vaccine antigens 1 month after Dose 3	Prespecified antibody levels to specific concomitant vaccine antigens 1 month after Dose 3	1 month after Dose 3
Geometric mean of antibody levels to measles, mumps, rubella, varicella, and hepatitis A virus antigens 1 month after Dose 4	Geometric mean of antibody levels to measles, mumps, rubella, varicella, and hepatitis A virus antigens 1 month after Dose 4	1 month after Dose 4
Geometric mean of immunoglobulin A (IgA) antibody levels to rotavirus 1 month after Dose 3	Geometric mean of IgA antibody levels to rotavirus 1 month after Dose 3	1 month after Dose 3

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 (Actual): May 29, 2026
• Primary Completion (Estimated): June 5, 2029
• Study Completion (Estimated): June 5, 2029

Study Registration Dates

• First Submitted: May 27, 2026
• First Submitted That Met QC Criteria: June 4, 2026
• First Posted (Actual): June 5, 2026

Study Record Updates

• Last Update Posted (Actual): June 5, 2026
• Last Update Submitted That Met QC Criteria: June 4, 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: C4931008

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