Safety, Tolerability, and Immunogenicity Study of a 31-Valent Pneumococcal Conjugate Vaccine (VAX-31) in Adults

NCT06151288 | Completed Phase 1 Results DMC FDA Drug

• 1 other identifier: VAX31-101
• Study Type: interventional
• Target: 1,015
• Locations: 1 country
• Sites: 25

Brief Summary

The objective of the study is to evaluate the safety, tolerability and immunogenicity of a single injection of VAX-31 at 3 dose levels compared to Prevnar 20™ (PCV20) in adults 50 to 64 years of age in Stage 1. Stage 2 will evaluate the safety, tolerability, and immunogenicity of a single injection of VAX-31 at 3 dose levels compared to PCV20 in adults aged 50 years and older.

Conditions

Pneumococcal Vaccines

Outcome Measures

Primary Outcomes (6)

• Percentage of Subjects Reporting Solicited Local Reactions Within 7 Days After Vaccination (Redness, Swelling, and Pain at Injection Site) in Each Age Group

  Solicited local reactions include redness/erythema, swelling/induration, and pain at injection site within 7 days after vaccination in each age group.

  7 days after vaccination

• Percentage of Subjects Reporting Solicited Systemic Events Within 7 Days After Vaccination (Fever, Headache, Fatigue, Muscle Pain, and Joint Pain) in Each Age Group Vaccination in Each Age Group

  Solicited systemic reactions include fever, headache, fatigue, muscle pain, and joint pain.

  7 days after vaccination

• Percentage of Subjects Reporting Unsolicited Adverse Event in Each Age Group

  Percentage of participants in each age group with adverse events (AEs) whose date of onset occurs after the study vaccine and within the 1 month after vaccination.

  1 month after vaccination

• Percentage of Subjects Reporting Serious Adverse Event

  Percentage of participants with SAEs.

  6 months after vaccination

• Percentage of Subjects Reporting New Onset of Chronic Illness

  Percentage of participants with NOCIs

  6 months after vaccination

• Percentage of Subjects Reporting Medically Attended Adverse Event

  Percentage of participants with MAAEs.

  6 months after vaccination

Secondary Outcomes (4)

• Percentage of Subjects With Adverse Events Due to Clinically Significant Laboratory Values

  1 month after vaccination

• Percentage of Participants With a Shift From Normal at Baseline to Abnormal at Post-vaccination in Safety Laboratory Parameters (Hematology, Clinical Chemistry, Urinalysis)

  1 month after vaccination

• 31 VAX-31 Pneumococcal Serotype-specific OPA Geometric Mean Titer

  1 month after vaccination

• 31 VAX-31 Pneumococcal Serotype-specific IgG Geometric Mean Concentration

  1 month after vaccination

Study Arms (4)

Group 1

EXPERIMENTAL

Participants received a single low dose of VAX-31 administered as an intramuscular injection at Day 1. 1.1 mcg for all serotypes with the exception of serotypes 1, 5, and 22F which is 1.65 mcg.

Biological: 31 valent pneumococcal conjugate vaccine

Group 2

EXPERIMENTAL

Participants received a single mid dose of VAX-31 administered as an intramuscular injection at Day 1. 2.2 mcg for all serotypes with the exception of serotypes 1, 5, and 22F which is 3.3 mcg.

Biological: 31 valent pneumococcal conjugate vaccine

Group 3

EXPERIMENTAL

Participants received a single high dose of VAX-31 administered as an intramuscular injection at Day 1. 3.3 mcg for all serotypes with the exception of serotypes 1, 5, and 22F which is 4.4 mcg.

Biological: 31 valent pneumococcal conjugate vaccine

Group 4

ACTIVE COMPARATOR

Participants received a single intramuscular injection of the standard dose of PCV20 at Day 1.

Biological: 20 valent pneumococcal conjugate vaccine

Interventions

31 valent pneumococcal conjugate vaccine BIOLOGICAL

0.5 ml dose of VAX-31 was administered into the deltoid muscle at Day 1

Group 1; Group 2; Group 3

20 valent pneumococcal conjugate vaccine BIOLOGICAL

0.5 ml dose of PCV20 was administered into the deltoid muscle at Day 1

Also known as: PCV20, Prevnar 20™

Group 4

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 aged 50 to 64 years (inclusive) for Stage 1, or 50 years and older (inclusive) for Stage 2 at the time of randomization into the study.
• Able and willing to complete the informed consent process.
• Available for clinical follow-up through the last study visit at 6 months after the study vaccination.
• In good general health as determined by medical history, vital signs, physical examination, and clinical judgment of the Investigator.
• Willing to have blood samples collected, stored indefinitely, and used for research purposes.
• Able to provide proof of identity to the satisfaction of the study staff completing the enrollment process.
• Women 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
• Able to access and use a smartphone, tablet, computer, or other device connected to Wi-Fi or cellular network for completion of an electronic diary.

You may not qualify if:

• Previous pneumococcal disease (either confirmed or self-reported).
• Previous receipt of a licensed or investigational pneumococcal vaccine.
• Receipt of any investigational study product within 30 days prior to enrollment into the study, currently participating in another interventional investigational study, or having plans to receive another investigational product(s) while on study.
• Planned or actual administration of any licensed vaccine during the period starting 30 days before enrollment into the study through Month 1.
• Physical examination indicating any clinically significant medical condition.
• Body Temperature \>38.0°C (\>100.4°F) or acute illness within 3 days prior to study vaccination (subject may be rescheduled).
• Previous or existing diagnosis of HIV, Hepatitis B, or Hepatitis C.
• History of severe allergic reaction with generalized urticaria, angioedema, or anaphylaxis.
• Female who is pregnant, breastfeeding, or planning to become pregnant during study participation.
• 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.
• Any other chronic or clinically significant medical condition that, in the opinion of the Investigator, would jeopardize the safety or rights of the subject or confound evaluation of the study vaccine.
• 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.
• Received blood or blood product (including Immune Globulin IV) within 90 days prior to enrollment into the study.
• Received systemic corticosteroids (except for inhaled, topical, intra-articular) for
• ≥14 consecutive days and has not completed treatment ≤30 days prior to enrollment into the study.

Sponsors & Collaborators

• Vaxcyte, Inc.: lead

Study Sites (25)

AMR Mobile

Mobile, Alabama, 36608, United States

Location

AMR Phoenix

Phoenix, Arizona, 85282, United States

Location

Research Centers of America

Hollywood, Florida, 33024, United States

Location

Health Awareness

Jupiter, Florida, 33458, United States

Location

Optimal Research

Melbourne, Florida, 32934, United States

Location

Precision Clinical Research

Sunrise, Florida, 33351, United States

Location

Velocity Clinical Research, Savannah

Savannah, Georgia, 31406, United States

Location

Healthcare Research Network II, LLC

Flossmoor, Illinois, 60422, United States

Location

Johnson County Clin-Trials

Lenexa, Kansas, 66219, United States

Location

DM Clinical Research - Detroit

Detroit, Michigan, 48076, United States

Location

Velocity Clinical Research Omaha

Omaha, Nebraska, 68134, United States

Location

WR-CRCN

Las Vegas, Nevada, 89106, United States

Location

Cenexel AMRI

Toms River, New Jersey, 08755, United States

Location

Rochester Clinical Research

Rochester, New York, 14609, United States

Location

CTI Clinical Research Center

Cincinnati, Ohio, 45212, United States

Location

Velocity Clinical Research, Cleveland

Cleveland, Ohio, 44122, United States

Location

DM Clinical Research - Philadelphia

Philadelphia, Pennsylvania, 19107, United States

Location

Velocity Clinical Research

Warwick, Rhode Island, 02886, United States

Location

Coastal Carolina Research

North Charleston, South Carolina, 29405, United States

Location

AMR Knoxville

Knoxville, Tennessee, 37909, United States

Location

Benchmark Research

Fort Worth, Texas, 76135, United States

Location

Benchmark Research

San Angelo, Texas, 76904, United States

Location

CenExel JBR Clinical Research

Salt Lake City, Utah, 84107, United States

Location

Charlottesville Medical Research

Charlottesville, Virginia, 22911, United States

Location

Health Research of Hampton Roads

Newport News, Virginia, 23606, United States

Location

Limitations and Caveats

Some limitations of this clinical study include the lack of a group, such as 3.3 mcg or 4.4 mcg, for all serotypes, aimed at understanding whether the dose response of polysaccharide can overcome carrier suppression. The relatively low ethnic diversity of participants is also a limitation, which will be addressed in larger phase 3 clinical trials.

Results Point of Contact

• Title: Study Director: Clinical Development
• Organization: Vaxcyte, Inc.

clinicaltrialsgov@vaxcyte.com

650-585-0029

Study Officials

• Clinical Development

  Vaxcyte, Inc.

  STUDY DIRECTOR

Publication Agreements

• PI is Sponsor Employee: No
• Restriction Type: OTHER
• Restrictive Agreement: Yes

Study Design

• Study Type: interventional
• Phase: phase 1
• 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: November 10, 2023
• First Posted: November 30, 2023
• Study Start: November 8, 2023
• Primary Completion: July 17, 2024
• Study Completion: July 17, 2024
• Last Updated: July 28, 2025
• Results First Posted: July 28, 2025

Record last verified: 2025-07

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL
• Time Frame: Individual participant data will be shared after deidentification and made available starting 6 months after initial product approval.
• Access Criteria: Criteria will depend on the specific proposal received and may include qualification of the scientific researchers, potential contribution to the research field, scientific rigor of statistical and analytical methods, and other criteria appropriate for the proposal.

Locations

US (25)