A Study to Assess the Safety, Tolerability, and Immunogenicity of 3 Lots of a Multivalent Pneumococcal Conjugate Vaccine Administered to Adults

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

The purpose of this study is to provide safety data and demonstrate lot consistency with the PG4 vaccine by evaluating the immunogenicity of 3 different lots of this vaccine.

This study will compare a new pneumococcal vaccine with the vaccine currently in use to see if they are similarly safe. It will also compare three batches of the new vaccine to make sure they work the same way. Blood samples will be taken to measure how the body responds to the vaccines.

The study will be conducted in the United States. Participants will be assigned to 1 of 4 groups. Group 1: PG4 vaccine lot 1; Group 2: PG4 vaccine lot 2; Group 3: PG4 vaccine lot 3; Group 4: 20vPnC.

Within each group, participants will be assigned by chance in a 2:2:2:1 ratio to receive 1 vaccine injection (shot) with either PG4 (new vaccine) lot 1, PG4 lot 2, PG4 Lot 3 or 20vPnC, given in the arm. This means that for every 7 participants, about 2 will receive either PG4 lot 1, lot 2 or lot 3 and about 1 will receive 20vPnC.

Each participant will take part in the study for approximately 6 months.

Study Overview

• Status: Not yet recruiting
• Conditions: Pneumococcal Disease
• Intervention / Treatment: Biological: PG4 Multivalent Vaccine; Biological: 20 Valent Pneumococcal Conjugate Vaccine (20vPnC)

• Study Type: Interventional
• Enrollment (Estimated): 4670
• 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

• United States
  • California
    • Lake Forest, California, United States, 92630
      • Orange County Research Center
    • Walnut Creek, California, United States, 94598
      • Diablo Clinical Research, LLC dba Flourish Research
  • Connecticut
    • Milford, Connecticut, United States, 06460
      • Clinical Research Consulting
  • Florida
    • Doral, Florida, United States, 33172
      • Suncoast Research Associates
    • Miami, Florida, United States, 33176
      • Entrust Clinical Research
    • Miami Lakes, Florida, United States, 33014
      • Palm Springs Community Health Center
    • Miami Lakes, Florida, United States, 33016
      • Indago Research and Health Center, Inc.
    • West Palm Beach, Florida, United States, 33409
      • Palm Beach Research Center
  • Georgia
    • Fayetteville, Georgia, United States, 30214
      • Javara Inc.
    • Stockbridge, Georgia, United States, 30281
      • Clinical Research Atlanta
  • Hawaii
    • Honolulu, Hawaii, United States, 96814
      • East-West Medical Research Institute
  • Illinois
    • Melrose Park, Illinois, United States, 60160
      • DM Clinical Research
  • Iowa
    • Sioux City, Iowa, United States, 51106
      • Velocity Clinical Research, Sioux City
  • Michigan
    • Grosse Pointe Woods, Michigan, United States, 48236
      • Henry Ford St. John Hospital - Thomas Mackey Center for Infectious Disease Research
  • Missouri
    • Chesterfield, Missouri, United States, 63005
      • Clinical Research Professionals
  • Nebraska
    • Grand Island, Nebraska, United States, 68803
      • Velocity Clinical Research, Grand Island
  • North Carolina
    • Wilmington, North Carolina, United States, 28401
      • Accellacare - Wilmington
  • Ohio
    • Cincinnati, Ohio, United States, 45212
      • CTI Clinical Research Center
  • South Carolina
    • Moncks Corner, South Carolina, United States, 29461
      • Clinical Trials of South Carolina
    • Myrtle Beach, South Carolina, United States, 29572
      • TMA Headlands LLC (d/b/a Trial Management Associates)
  • Texas
    • Mesquite, Texas, United States, 75149
      • SMS Clinical Research LLC
    • Sugar Land, Texas, United States, 77478
      • DM Clinical Research - Sugar Land
    • Tomball, Texas, United States, 77375
      • DM Clinical Research
  • Utah
    • Salt Lake City, Utah, United States, 84109
      • J. Lewis Research, Inc. / Foothill Family Clinic
    • Salt Lake City, Utah, United States, 84121
      • J. Lewis Research, Inc. / Foothill Family Clinic South

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

Adults 18 through 49 years of age, who have no history of receiving a pneumococcal vaccine after 5 years of age.

Exclusion Criteria:

Individuals with a history of severe allergic reactions to a vaccine or its components, serious chronic medical disorders, significant psychiatric conditions, known or suspected immunodeficiency, substance abuse issues, asplenia, bleeding diathesis or prolonged bleeding, a history of a prior confirmed invasive pneumococcal infection, and pregnant or breastfeeding females will be excluded from enrollment 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

4

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: PG4 Vaccine Lot 1; Multivalent Pneumococcal Vaccine	Biological: PG4 Multivalent Vaccine; Multivalent Pneumococcal Vaccine; Other Names: PG4 Lot 3
Experimental: PG4 Vaccine Lot 2; Multivalent Pneumococcal Vaccine	Biological: PG4 Multivalent Vaccine; Multivalent Pneumococcal Vaccine; Other Names: PG4 Lot 3
Experimental: PG4 Vaccine Lot 3; Multivalent Pneumococcal Vaccine	Biological: PG4 Multivalent Vaccine; Multivalent Pneumococcal Vaccine; Other Names: PG4 Lot 3
Active Comparator: 20 Valent Pneumococcal Conjugate Vaccine (20vPnC); 20 Valent Pneumococcal Conjugate Vaccine	Biological: 20 Valent Pneumococcal Conjugate Vaccine (20vPnC); 20 Valent Pneumococcal Conjugate Vaccine; Other Names: Prevnar 20

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Percentage of Participants with Prespecified Local Reactions Within 7 Days After Vaccination	Prompted local reactions after each dose	Within 7 days after Vaccination
Percentage of Participants reporting Prespecified Systemic Events Within 7 Days after Vaccination	Prompted systemic events after each dose	Within 7 days after Vaccination
Percentage of Participants with Adverse Events (AEs)	AEs occurring from Dose 1 to 1 month after the vaccination	From Vaccination to 1 month after Vaccination
Percentage of Participants with Serious Adverse Events (SAEs)	SAEs occurring from Dose 1 to 6 months after the vaccination	From Vaccination to 6 months after Vaccination
OPA geometric mean ratios (GMR) between each pair of PG4 vaccine lots	OPA GMRs between each pair of PG4 vaccine lots at 1 month after vaccination	1 month after Vaccination

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
OPA Serotype-specific geometric mean titers (GMT) for PG4 vaccine serotypes	OPA GMTs at 1 month after vaccination	1 month after Vaccination
OPA geometric mean fold rise (GMFR) for PG4 vaccine serotypes	GMFRs in OPA titers from before to 1 month after vaccination	From before vaccination to 1 month after vaccination
Percentages of participants with a ≥4-fold rise in opsonophagocytic activity (OPA) titers	Percentages of participants with a ≥4-fold rise in OPA titers from before to 1 month after vaccination	From Vaccination to 6 months after Vaccination
Percentages of participants with OPA titers ≥ lower limit of quantitation (LLOQ)	Percentages of participants with OPA titers ≥ lower limit of quantitation (LLOQ) from before vaccination to 1 month after vaccination	From before vaccination 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): September 8, 2026
• Primary Completion (Estimated): June 7, 2027
• Study Completion (Estimated): June 7, 2027

Study Registration Dates

• First Submitted: August 26, 2026
• First Submitted That Met QC Criteria: August 26, 2026
• First Posted (Actual): August 31, 2026

Study Record Updates

• Last Update Posted (Actual): August 31, 2026
• Last Update Submitted That Met QC Criteria: August 26, 2026
• Last Verified: August 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: C4931012

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