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NCT Number: NCT07794748

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

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Key information

Conditions

Pneumococcal Disease Bacterial Infections Bacterial Infections and Mycoses Gram-Positive Bacterial Infections Infections Pneumococcal Infections Streptococcal Infections

Age range

18 year–49 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 3

Primary location

Orange County Research Center, Lake Forest, California, United States

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Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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.

Treatment and study plan

PG4 Multivalent Vaccine

Biological

Multivalent Pneumococcal Vaccine

Other names: PG4 lot 1

20 Valent Pneumococcal Conjugate Vaccine (20vPnC)

Biological

20 Valent Pneumococcal Conjugate Vaccine

Other names: Prevnar 20

Primary outcomes

  1. Percentage of Participants with Prespecified Local Reactions Within 7 Days After Vaccination

    Time frame: Within 7 days after Vaccination

    Prompted local reactions after each dose

  2. Percentage of Participants reporting Prespecified Systemic Events Within 7 Days after Vaccination

    Time frame: Within 7 days after Vaccination

    Prompted systemic events after each dose

  3. Percentage of Participants with Adverse Events (AEs)

    Time frame: From Vaccination to 1 month after Vaccination

    AEs occurring from Dose 1 to 1 month after the vaccination

  4. Percentage of Participants with Serious Adverse Events (SAEs)

    Time frame: From Vaccination to 6 months after Vaccination

    SAEs occurring from Dose 1 to 6 months after the vaccination

  5. OPA geometric mean ratios (GMR) between each pair of PG4 vaccine lots

    Time frame: 1 month after Vaccination

    OPA GMRs between each pair of PG4 vaccine lots at 1 month after vaccination

Secondary outcomes

  1. OPA Serotype-specific geometric mean titers (GMT) for PG4 vaccine serotypes

    Time frame: 1 month after Vaccination

    OPA GMTs at 1 month after vaccination

  2. OPA geometric mean fold rise (GMFR) for PG4 vaccine serotypes

    Time frame: From before vaccination to 1 month after vaccination

    GMFRs in OPA titers from before to 1 month after vaccination

  3. Percentages of participants with a ≥4-fold rise in opsonophagocytic activity (OPA) titers

    Time frame: From Vaccination to 6 months after Vaccination

    Percentages of participants with a ≥4-fold rise in OPA titers from before to 1 month after vaccination

  4. Percentages of participants with OPA titers ≥ lower limit of quantitation (LLOQ)

    Time frame: From before vaccination to 1 month after vaccination

    Percentages of participants with OPA titers ≥ lower limit of quantitation (LLOQ) from before vaccination to 1 month after vaccination

Study contacts

Contact information is provided by the study sponsor or research team.

Pfizer CT.gov Call Center

CONTACT

[email protected]

1-800-718-1021

Sponsors and collaborators

Lead sponsor

Pfizer

Industry

Registry information

Official study title

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

Important dates

Study start
2026
Primary completion
2027
Study completion
2027
First posted
Aug 31, 2026
Registry last updated
Aug 31, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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