Safety, Tolerability, and Immunogenicity of VAX-31 in Adults ≥50 Years With Prior Pneumococcal Vaccination

NCT07425392 | Active Not Recruiting Phase 3 DMC FDA Drug

• 1 other identifier: VAX31-105
• Study Type: interventional
• Target: 752
• Locations: 1 country
• Sites: 30

Brief Summary

The study will evaluate the safety, tolerability, and immunogenicity of VAX-31 in adults ≥50 years of age.

Conditions

Pneumococcal Vaccines

Keywords

Pneumonia; Pneumococcal Infection; 31-Valent PCV

Outcome Measures

Primary Outcomes (6)

• Serotype-specific OPA geometric mean titers (GMT)

  1 month after VAX-31 vaccination

• Serotype-specific OPA geometric mean fold rise (GMFR) from baseline

  1 month after VAX-31 vaccination

• Percentage of subjects reporting solicited local adverse events (AE) (redness, swelling, and pain at injection site)

  up to 7 days after vaccination

• Percentage of subjects reporting solicited systemic AE (fever, headache, fatigue, muscle pain, and joint pain)

  up to 7 days after vaccination

• Percentage of subjects reporting unsolicited AE

  up to 31 days after vaccination

• Percentage of subjects reporting new onset of chronic illness (NOCI), medically attended AE (MAAE), and serious adverse events (SAE)

  up to 6 months after vaccination

Secondary Outcomes (2)

• Serotype-specific IgG geometric mean concentration (GMC)

  1 month after VAX-31 vaccination

• Serotype-specific IgG geometric mean fold-rise (GMFR) from baseline

  1 month after VAX-31 vaccination

Study Arms (6)

Cohort 1 (VAX-31): Prior PPSV23

EXPERIMENTAL

Participants will receive a single dose of VAX-31 administered via intramuscular injection at Day 1

Biological: 31-valent pneumococcal conjugate vaccine

Cohort 1 (PCV20): Prior PPSV23

ACTIVE COMPARATOR

Participants will receive a single dose of PCV20 (Prevnar 20) administered via intramuscular injection at Day 1

Biological: PCV20

Cohort 2 (VAX-31): Prior PCV20

EXPERIMENTAL

Participants will receive a single dose of VAX-31 administered via intramuscular injection at Day 1

Biological: 31-valent pneumococcal conjugate vaccine

Cohort 2 (PCV20): Prior PCV20

ACTIVE COMPARATOR

Participants will receive a single dose of PCV20 (Prevnar 20) administered via intramuscular injection at Day 1

Biological: PCV20

Cohort 3 (VAX-31): Other prior licensed pneumococcal vaccine or combination

EXPERIMENTAL

Participants will receive a single dose of VAX-31 administered via intramuscular injection at Day 1

Biological: 31-valent pneumococcal conjugate vaccine

Cohort 3 (PCV20): Other prior licensed pneumococcal vaccine or combination

ACTIVE COMPARATOR

Participants will receive a single dose of PCV20 (Prevnar 20) administered via intramuscular injection at Day 1

Biological: PCV20

Interventions

31-valent pneumococcal conjugate vaccine BIOLOGICAL

0.5 mL of VAX-31 will be administered into the deltoid muscle

Cohort 1 (VAX-31): Prior PPSV23; Cohort 2 (VAX-31): Prior PCV20; Cohort 3 (VAX-31): Other prior licensed pneumococcal vaccine or combination

PCV20 BIOLOGICAL

0.5 mL of the 20-valent pneumococcal conjugate vaccine will be administered into the deltoid muscle

Cohort 1 (PCV20): Prior PPSV23; Cohort 2 (PCV20): Prior PCV20; Cohort 3 (PCV20): Other prior licensed pneumococcal vaccine or combination

Eligibility Criteria

• Age: 50 Years+
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Male or female ≥50 years of age (inclusive) at the time of randomization into the study.
• Previous receipt of a licensed pneumococcal vaccine or combination of licensed vaccines, with most recent vaccination ≥1 year prior to randomization; the exception is PCV21, which may have been received ≥6 months prior to randomization (confirmed).
• Able and willing to complete the informed consent process.
• Available for clinical follow-up through the last study visit.
• In good general health or with stable underlying chronic condition(s), as determined by medical history, oral temperature, physical examination, and clinical judgment of the Investigator (ongoing chronic conditions must be documented as stable per Investigator).
• Willing to have blood samples collected and used for research purposes.
• Able to provide proof of identity to the satisfaction of the site personnel completing the enrollment process.
• Female participants of childbearing potential, defined as premenopausal females capable of becoming pregnant, must have a negative urine pregnancy test immediately prior to randomization and agree to use acceptable contraception. Male subjects with partners of childbearing potential must agree to practice an acceptable contraception method.
• Able to access and use a device connected to Wi-Fi or cellular network for completion of an electronic diary (eDiary).

You may not qualify if:

• Previous invasive pneumococcal disease (IPD) or pneumococcal pneumonia (either confirmed or self-reported) at any age.
• Previous receipt of an investigational pneumococcal vaccine at any age.
• Receipt of any investigational product within 30 days prior to Day 1, currently participating in another interventional investigational study, or having plans to receive another investigational product(s) while on study.
• Receipt of any live vaccine within 30 days prior to Day 1, or receipt of any non-live (including inactivated) vaccine within 14 days prior to Day 1.
• Body temperature \>38.0°C (\>100.4°F) or acute illness within 3 days prior to study vaccination (subject may be rescreened).
• Current diagnosis of human immunodeficiency virus, Hepatitis B, or Hepatitis C.
• History of severe allergic reaction with generalized urticaria, angioedema, or anaphylaxis to any previous vaccination.
• Individual who is pregnant, breastfeeding, or planning to become pregnant during study participation.
• Has a known or suspected immunocompromising condition, including, but not limited to, leukemia, lymphoma, chronic renal failure, or congenital or acquired immunodeficiency.
• Bleeding disorder diagnosed by a doctor (e.g., factor deficiency, coagulopathy, or platelet disorder requiring special precautions) resulting in clinically significant bruising or bleeding difficulties with IM injections or blood draws.
• Receipt of blood or blood product (including polyclonal intravenous immunoglobulin) within 60 days prior to enrollment into the study.
• Is currently receiving immunosuppressive or immune-modifying therapy, including systemic corticosteroids (this includes ≥3 months of prednisone equivalent from 5 to ≤10 mg/day and ≥2 weeks of prednisone equivalent \>10 mg/day).
• Received any part of a ≥14-day course of systemic corticosteroids (prednisone equivalent \>10 mg/day) within 14 days of study vaccination
• History of malignancy ≤5 years before enrollment, except for adequately treated basal cell or squamous cell skin cancer or in situ cervical cancer.
• Any medical, psychiatric, or social condition that in the judgment of the Investigator is a contraindication to protocol participation or impairs a subject's ability to give informed consent.

Sponsors & Collaborators

• Vaxcyte, Inc.: lead

Study Sites (30)

Chinle Center for Indigenous Health

Chinle, Arizona, 86503, United States

Location

Avacare (CCT Research)

Phoenix, Arizona, 85044, United States

Location

Whiteriver Center for Indigenous Health

Whiteriver, Arizona, 85941, United States

Location

Chase Medical Research

Waterbury, Connecticut, 06708, United States

Location

CenExel (RCA)

Hollywood, Florida, 33024, United States

Location

Eximia (Health Awareness)

Jupiter, Florida, 33458, United States

Location

Eximia (Health Awareness)

Port Saint Lucie, Florida, 34952, United States

Location

Precision Clinical Research

Sunrise, Florida, 33351, United States

Location

The Villages

The Villages, Florida, 32162, United States

Location

DelRicht Clinical Research

Stockbridge, Georgia, 30281, United States

Location

Velocity Clinical Valparaiso

Valparaiso, Indiana, 46383, United States

Location

Johnson County Clin-Trials, LLC

Lenexa, Kansas, 66219, United States

Location

DelRicht Clinical Research

New Orleans, Louisiana, 70115, United States

Location

Velocity (Meridian Clinical Research)

Rockville, Maryland, 20854, United States

Location

DM Clinical Research-Detroit

Southfield, Michigan, 48076, United States

Location

AMR

Kansas City, Missouri, 64114, United States

Location

DelRicht Research (Command Family Medicine)

Springfield, Missouri, 65807, United States

Location

Quality Clinical Research

Omaha, Nebraska, 68114, United States

Location

Center of American Indian Health

Gallup, New Mexico, 87301, United States

Location

Shiprock Center for Indigenous Health

Shiprock, New Mexico, 87420, United States

Location

Rochester Clinical Research, Inc.

Rochester, New York, 14609, United States

Location

Headlands (Trial Management Associates)

Wilmington, North Carolina, 28403, United States

Location

Tekton Research

Edmond, Oklahoma, 73013, United States

Location

DelRicht Research

Hendersonville, Tennessee, 37075, United States

Location

Tekton Research

Austin, Texas, 78745, United States

Location

REX Clinical Trials

Beaumont, Texas, 77701, United States

Location

Flourish Research

San Antonio, Texas, 78229, United States

Location

DM Clinical Research

Sugar Land, Texas, 77478, United States

Location

Alcanza (Charlottesville Medical Research)

Charlottesville, Virginia, 22911, United States

Location

Health Research of Hampton Roads, Inc.

Newport News, Virginia, 23606, United States

Location

MeSH Terms

Conditions

Pneumonia; Pneumococcal Infections

Condition Hierarchy (Ancestors)

Respiratory Tract Infections; Infections; Lung Diseases; Respiratory Tract Diseases; Streptococcal Infections; Gram-Positive Bacterial Infections; Bacterial Infections; Bacterial Infections and Mycoses

Study Design

• Study Type: interventional
• Phase: phase 3
• Allocation: RANDOMIZED
• Masking: QUADRUPLE
• Who Masked: PARTICIPANT, CARE PROVIDER, INVESTIGATOR, OUTCOMES ASSESSOR
• Purpose: PREVENTION
• Intervention Model: PARALLEL
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: February 11, 2026
• First Posted: February 20, 2026
• Study Start: February 9, 2026
• Primary Completion (Estimated): March 1, 2027
• Study Completion (Estimated): March 1, 2027
• Last Updated: June 30, 2026

Record last verified: 2026-06

Locations

US (30)