Lot-to-lot Consistency Study of a 21-valent Pneumococcal Conjugate Vaccine in Healthy Infants From 2 Months of Age

A Phase 3, Randomized, Modified Double-blind, Active-controlled, Parallel-group, Lot-to-lot Consistency, 4-arm Study to Investigate the Safety and Immunogenicity of a 4-dose Regimen of a 21-valent Pneumococcal Conjugate Vaccine in Healthy Infants and Toddlers

This is a phase 3 randomized, modified double-blind study whose purpose is to measure whether 3 lots of the investigational pneumococcal vaccine PCV21 can help the body to develop germ-fighting agents called "antibodies" (immunogenicity) in a similar way (ie, same immune response) when they are given to infants aged from approximately 2 months (42 to 89 days) and are safe compared to a licensed 20-valent pneumococcal vaccine (20vPCV) (Prevnar 20™).

The study duration per participant will be up to approximately 17 months. The study vaccines (either PCV21 or 20vPCV) will be administered at approximately 2, 4, 6 and 12 months of age. Cohort A will include randomization to three PCV21 formulation groups or one 20vPCV comparator group (Group 1-4, approximately 896 total participants), whereas Cohort B will include randomization to three PCV21 formulation groups only (Groups 1-3, approximately 1299 total participants). Routine pediatric vaccines will be given as per local recommendations.

There will be 6 study visits: Visit (V)01, V02 separated from V01 by 60 days, V03 separated from V02 by 60 days, V04 separated from V03 by 30 days, V05 at 12 months of age, V06 separated from V05 by 30 days

Study Overview

• Status: Recruiting
• Conditions: Healthy Volunteers; Pneumococcal Immunization
• Intervention / Treatment: Biological: PCV21 vaccine; Biological: 20vPCV licensed vaccine

• Study Type: Interventional
• Enrollment (Estimated): 2195
• Phase: Phase 3

Contacts and Locations

• Study Contact: Name: Trial Transparency email recommended (Toll free for US & Canada); Phone Number: option 6 800-633-1610; Email: Contact-US@sanofi.com

Study Locations

• Honduras
  • San Pedro Sula, Honduras, 21104
    • Recruiting
    • Investigational Site Number : 3400001
  • Tegucigalpa, Honduras, 11101
    • Recruiting
    • Investigational Site Number : 3400003
  • Tegucigalpa, Honduras, 11101
    • Recruiting
    • Investigational Site Number : 3400002
• Puerto Rico
  • Guayama, Puerto Rico, 00786
    • Recruiting
    • Investigational Site Number : 6300005
  • San Juan, Puerto Rico, 00918
    • Recruiting
    • Investigational Site Number : 6300006
  • Trujillo Alto, Puerto Rico, 00976
    • Recruiting
    • Investigational Site Number : 6300007
• United States
  • Arkansas
    • Fayetteville, Arkansas, United States, 72703
      • Recruiting
      • Northwest Arkansas Pediatric Clinic- Site Number : 8400039
  • California
    • Huntington Park, California, United States, 90255
      • Recruiting
      • Matrix Clinical Research - Huntington Park- Site Number : 8400029
    • Los Angeles, California, United States, 90008
      • Recruiting
      • Community Clinical Research- Site Number : 8400030
    • Los Angeles, California, United States, 90057
      • Recruiting
      • Matrix Clinical Research - Los Angeles- Site Number : 8400028
  • Florida
    • Tampa, Florida, United States, 33613
      • Recruiting
      • PAS Research - Tampa- Site Number : 8400034
  • Kentucky
    • Bardstown, Kentucky, United States, 40004
      • Recruiting
      • Kentucky Pediatric Research- Site Number : 8400036
  • Michigan
    • Allen Park, Michigan, United States, 48101
      • Recruiting
      • Michigan Institute of Research- Site Number : 8400004
  • South Carolina
    • Charleston, South Carolina, United States, 29407
      • Recruiting
      • Tribe Clinical Research At Neighbors Pediatrics- Site Number : 8400008
    • Simpsonville, South Carolina, United States, 29681
      • Recruiting
      • Parkside Pediatrics - Simpsonville- Site Number : 8400005
    • Spartanburg, South Carolina, United States, 29301
      • Recruiting
      • Tribe Clinical Research - Spartanburg- Site Number : 8400026
  • Texas
    • Edinburg, Texas, United States, 78539
      • Recruiting
      • PAS Research - Children's Care Clinic- Site Number : 8400035
    • Richmond, Texas, United States, 77469
      • Recruiting
      • Pediatric Center - Richmond- Site Number : 8400038
  • Utah
    • Ogden, Utah, United States, 84404
      • Recruiting
      • Rio Clinical Trials - Canyon View- Site Number : 8400031

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Aged 42 to 89 days on the day of inclusion
• Participants who are healthy as determined by medical evaluation including medical history and physical examination
• Born at full term of pregnancy (≥ 37 weeks) and with a birth weight ≥ 2.5 kg or born after a gestation period above 28 (> 28 weeks) through 36 weeks with a birth weight ≥ 1.5 kg, and in both cases medically stable

Exclusion Criteria:

• Known or suspected congenital or acquired immunodeficiency; or receipt of immunosuppressive therapy, such as anti-cancer chemotherapy or radiation therapy; or long-term systemic corticosteroid therapy
• History of microbiologically confirmed Streptococcus pneumoniae infection or disease
• Any contraindication to the routine pediatric vaccine being administered in the study
• History of seizure or significant stable or progressive neurologic disorders such as infantile spasms, inflammatory nervous system diseases, encephalopathy, cerebral palsy
• Known systemic hypersensitivity to any of the study interventions components, or history of a life-threatening reaction to the study interventions used in the study or to a product containing any of the same substances3
• Laboratory-confirmed or known thrombocytopenia, as reported by the parent(s) / legally acceptable representative (LAR(s)), contraindicating intramuscular (IM) injection.
• Bleeding disorder, or receipt of anticoagulants in the 3 weeks preceding inclusion, contraindicating IM injection.
• Chronic illness that, in the opinion of the investigator, is at a stage where it might interfere with study conduct or completion
• Moderate or severe acute illness/infection (according to investigator judgment) or febrile illness (temperature ≥ 38.0°C [≥ 100.4°F]) on the day of study intervention administration.
• Receipt of any BCG vaccine within 4 weeks preceding the first study intervention administration or planned receipt any BCG vaccine within the study period
• Previous vaccination against Streptococcus pneumoniae
• Previous vaccination against the following antigens: diphtheria, tetanus, pertussis, H. influenzae type b, poliovirus
• Receipt of more than 1 dose of hepatitis B vaccine
• Receipt of immune globulins, blood or blood-derived products since birth
• Participation at the time of study enrollment (or in the 6 weeks preceding the first study intervention administration) or planned participation during the present study period in another clinical study investigating a vaccine, drug, medical device, or medical procedure

Note: The above information is not intended to contain all considerations relevant to a potential participation in a clinical trial.

Study Plan

How is the study designed?

Design Details

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

Number of Arms

4

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Group 1: PCV21; Participants will be administered via intramuscular injection (IM) PCV21 vaccine lot 1 for Doses 1, 2 and 3; PCV21 lot 1, or different lot if needed, for Dose 4 at 2, 4, 6 and 12 months of age co-administered with routine pediatric vaccines.	Biological: PCV21 vaccine; Pharmaceutical form: Suspension for injection Route of administration: Intramuscular; Other Names: 515
Experimental: Group 2: PCV21; Participants will be administered via IM injection PCV21 vaccine lot 2 for Doses 1, 2 and 3; PCV21 lot 2, or different lot if needed, for Dose 4 at 2, 4, 6 and 12 months of age co-administered with routine pediatric vaccines.	Biological: PCV21 vaccine; Pharmaceutical form: Suspension for injection Route of administration: Intramuscular; Other Names: 515
Experimental: Group 3: PCV21; Participants will be administered via IM injection PCV21 vaccine lot 3 for Doses 1, 2 and 3; PCV21 lot 3, or different lot if needed, for Dose 4 at 2, 4, 6 and 12 months of age co-administered with routine pediatric vaccines.	Biological: PCV21 vaccine; Pharmaceutical form: Suspension for injection Route of administration: Intramuscular; Other Names: 515
Active Comparator: Group 4: 20vPCV (Cohort A only); Participants will be administered via IM injection 20vPCV at 2, 4, 6 and 12 months of age co-administered with routine pediatric vaccines.	Biological: 20vPCV licensed vaccine; Pharmaceutical form: Suspension for injection Route of administration: Intramuscular; Other Names: Prevnar 20™

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
For all participants: Serotype specific Immunoglobulin g (IgG) Geometric Mean Concentration (GMC)	Serotype specific IgG concentrations for all serotypes included in PCV21 vaccine as measured by electrochemiluminescence assay (ECL)	30 days after the third dose of PCV21 vaccine

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
For all participants: Serotype specific IgG concentration ≥ 0.35 µg/mL	Serotype specific IgG concentration ≥ 0.35 μg/mL (seroresponse) for all serotypes included in PCV21 as measured by ECL	30 days after the third dose of PCV21 vaccine
For all participants: Presence of any immediate adverse events (AEs)	Number of participants experiencing immediate AEs	Within 30 minutes after each vaccine injection
For participants in Cohort A (reactogenicity subset): Presence of solicited injection site and systemic reactions through 7 days after each vaccine injection	Number of participants experiencing solicited injection site and systemic reactions	Through 7 days after each vaccine injection
For all participants: Presence of unsolicited (spontaneously reported) injection site reactions and unsolicited systemic AEs	Number of participants experiencing unsolicited injection site reactions and unsolicited systemic AEs	Through 30 days after each vaccine injection
For all participants: Presence of serious adverse events (SAEs) and adverse events of special interest (AESIs) throughout the study	Number of participants experiencing SAEs and AESIs	Throughout the study (through 6 months post-last vaccine injection)

Collaborators and Investigators

• Sponsor: Sanofi

Publications and helpful links

Helpful Links

• PSK00029 Plain Language Results Summary

Study record dates

Study Major Dates

• Study Start (Actual): January 20, 2026
• Primary Completion (Estimated): June 7, 2027
• Study Completion (Estimated): May 29, 2028

Study Registration Dates

• First Submitted: January 15, 2026
• First Submitted That Met QC Criteria: January 15, 2026
• First Posted (Actual): January 16, 2026

Study Record Updates

• Last Update Posted (Actual): May 22, 2026
• Last Update Submitted That Met QC Criteria: May 21, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: Pneumococcal Infection; 21 Valent Pneumococcal Vaccine
• Additional Relevant MeSH Terms: Infections; Gram-Positive Bacterial Infections; Bacterial Infections; Bacterial Infections and Mycoses; Streptococcal Infections; Pneumococcal Infections; Biological Products; Complex Mixtures; Vaccines; Vaccines, Combined; Measles Vaccine; Viral Vaccines; Mumps Vaccine; Rubella Vaccine; Viral Hepatitis Vaccines; Herpesvirus Vaccines; Measles-Mumps-Rubella Vaccine; Hepatitis A Vaccines; Chickenpox Vaccine; Rotavirus Vaccines; RotaTeq; RIX4414 vaccine; Vaxelis
• Other Study ID Numbers: PSK00029 (Other Identifier: Sanofi Identifier); U1111-1308-6832 (Other Identifier: WHO ICTRP)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Qualified researchers may request access to patient level data and related study documents including the clinical study report, study protocol with any amendments, blank case report form, statistical analysis plan, and dataset specifications. Patient level data will be anonymized and study documents will be redacted to protect the privacy of trial participants. Further details on Sanofi's data sharing criteria, eligible studies, and process for requesting access can be found at: https://vivli.org

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No