Study of the Safety and Immunogenicity of Catch-up Vaccination With a 21-valent Pneumococcal Conjugate Vaccine (PCV21) in Healthy Infants, Toddlers, Children, and Adolescents

A Phase 3, Randomized, Modified Double-blind, Active-controlled, Parallel-group Study to Investigate the Safety and Immunogenicity of Catch-up Vaccination Regimens of a 21-valent Pneumococcal Conjugate Vaccine in Healthy Infants, Toddlers, Children, and Adolescents

The purpose of this study is to evaluate the safety and immunogenicity of PCV21 versus 20vPCV ( 20-valent pneumococcal conjugate vaccine, Prevnar 20) for catch-up vaccination in infants (7 to 11 MoA-Months of age), toddlers (12 to 23 MoA), and children/adolescents (2 to 5 YoA and 6 to 17 YoA-years of age).

Study Overview

• Status: Active, not recruiting
• Conditions: Pneumococcal Infections
• Intervention / Treatment: Biological: PCV21; Biological: 20vPCV

Detailed Description

The duration of each participation will be approximately 9 to 11 months for each infant participant, 8 to 9 months for each toddler participant, and 6 months for each child/adolescent participant.

• Study Type: Interventional
• Enrollment (Actual): 1268
• Phase: Phase 3

Contacts and Locations

Study Locations

• Estonia
  • Tartu, Estonia, 50708
    • Site # 2330004
  • Harju
    • Tallinn, Harju, Estonia, 10117
      • Site # 2330006
    • Tallinn, Harju, Estonia, 13619
      • Site # 2330007
    • Tallinn, Harju, Estonia, EE-10617
      • Site # 2330002
    • Tallinn, Harju, Estonia, EE-10617
      • Site # 2330003
  • Järvamaa
    • Paide, Järvamaa, Estonia, 72713
      • Site # 2330001
  • Tartu
    • Tartu, Tartu, Estonia, 50106
      • Site # 2330005
• Poland
  • Bydgoszcz, Poland, 85-048
    • Site # 6160002
  • Bydgoszcz, Poland, 85-796
    • Site # 6160004
  • Kłodzko, Poland, 57-300
    • Site # 6160006
  • Torun, Poland, 87-100
    • Site # 6160001
  • Lodskie
    • Lodz, Lodskie, Poland, 91-341
      • Site # 6160009
  • Masovian Voivodeship
    • Warsaw, Masovian Voivodeship, Poland, 03-291
      • Site # 6160007
  • Silesian Voivodeship
    • Częstochowa, Silesian Voivodeship, Poland, 42-200
      • Site # 6160003
• Thailand
  • Bangkok, Thailand, 10270
    • Site # 7640008
  • Bangkok, Thailand, 10400
    • Site # 7640006
  • Bangkok, Thailand, 10400
    • Site # 7640007
  • Chiang Mai, Thailand, 50200
    • Site # 7640004
  • Pathum Thani, Thailand
    • Site # 7640001
  • Changwat Songkhla
    • Hat Yai, Changwat Songkhla, Thailand, 90112
      • Site # 7640002
  • Chiang Mai
    • Mueang Nonthaburi, Chiang Mai, Thailand, 50200
      • Site # 7640003
• United States
  • California
    • Paramount, California, United States, 90723
      • Site # 8400008
  • Florida
    • Doral, Florida, United States, 33166
      • Site # 8400024
    • Hialeah, Florida, United States, 33012
      • Site # 8400007
    • Melbourne, Florida, United States, 32934
      • Site # 8400014
    • Miami, Florida, United States, 33166
      • Site # 8400009
    • Miami, Florida, United States, 33166
      • Site # 8400016
  • Georgia
    • Fayetteville, Georgia, United States, 30214
      • Site # 8400021
    • Union City, Georgia, United States, 30291
      • Site # 8400004
  • Iowa
    • Sioux City, Iowa, United States, 51106
      • Site # 8400003
  • Kentucky
    • Erlanger, Kentucky, United States, 41018
      • Site # 8400023
  • Mississippi
    • Biloxi, Mississippi, United States, 39531
      • Site # 8400018
    • Ridgeland, Mississippi, United States, 39531
      • Site # 8400012
  • Nebraska
    • Omaha, Nebraska, United States, 68114
      • Site # 8400002
  • New York
    • Binghamton, New York, United States, 13905
      • Site #8400010
    • Rochester, New York, United States, 14642
      • Site # 8400025
  • Texas
    • Houston, Texas, United States, 77065
      • Site # 8400001
    • Stephenville, Texas, United States, 76401
      • Site # 8400017

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

AGE

• Aged 7 months to 17 years on the day of inclusion

TYPE OF PARTICIPANT AND DISEASE CHARACTERISTICS

• Participants who are healthy as determined by medical evaluation including medical history and physical examination

For infants (7 to 11 MoA) and toddlers (12 to 23 MoA) only

• 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 as assessed by the investigator

SEX, CONTRACEPTIVE/BARRIER METHOD AND PREGNANCY TESTING REQUIREMENTS For adolescents (6 to 17 YoA) only

• A female participant is eligible to participate if she is not pregnant or breastfeeding and one of the following conditions applies:
• Is of non-childbearing potential. To be considered of non-childbearing potential, a female must be pre-menarche or surgically sterile. OR
• Is of childbearing potential and agrees to use an effective contraceptive method or abstinence from at least 4 weeks prior to the study vaccine administration until at least 4 weeks after the study vaccine administration. A female participant of childbearing potential must have a negative highly sensitive pregnancy test (urine or serum as required by local regulation) within 25 hours of before the first dose of study vaccine.

INFORMED CONSENT

• Assent form has been signed and dated by the participant (based on local regulations), and if applicable, and informed consent form has been signed and dated by the parent(s) or another legally acceptable representative (LAR) and by an independent witness, if required by local regulations

OTHER INCLUSIONS

• Participant and parent(s) / LAR(s) are able to attend all scheduled visits and to comply with all study procedures

Exclusion Criteria:

MEDICAL CONDITIONS

• Known or suspected congenital or acquired immunodeficiency; or receipt of immunosuppressive therapy, such as anti-cancer chemotherapy or radiation therapy, within the preceding 6 months; or long-term systemic corticosteroid therapy
• History of microbiologically confirmed S. pneumoniae infection or disease
• History of seizure or significant stable or progressive neurological disorders such as inflammatory nervous system diseases, encephalopathy, and cerebral palsy
• Known systemic hypersensitivity to any of the vaccine components, or history of a life-threatening reaction to the vaccines used in the study or to a product containing any of the same substances
• Laboratory-confirmed thrombocytopenia, or known thrombocytopenia, as reported by the parent(s) / 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 vaccine administration.

For infants (7 to 11 MoA) and toddlers (12 to 23 MoA) only

• Previous vaccination against S. pneumonia

For children (2 to 5 YoA) and adolescents (6 to 17 YoA) only

• Previous vaccination with pneumococcal polysaccharide vaccine

For adolescents (6 to 17 YoA) only

• Alcohol, prescription drug, or substance abuse that, in the opinion of the Investigator, might interfere with the study conduct or completion

PRIOR/CONCOMITANT THERAPY

• Receipt of any vaccine in the 4 weeks preceding the vaccine administration or planned receipt of any vaccine in the 4 weeks following the vaccine administration, except for US licensed influenza vaccination, which may be received at least 2 weeks before or 2 weeks after any study vaccination. This exception includes monovalent pandemic influenza vaccines and multivalent influenza vaccines, as applicable per local recommendations
• Receipt of immune globulins, blood or blood-derived products in the past 3 months

For children (2 to 5 YoA) and adolescents (6 to 17 YoA) only

• Receipt of oral or injectable antibiotic therapy within 72 hours prior to the first blood draw

PRIOR/CONCURRENT CLINICAL STUDY EXPERIENCE

• Participation at the time of study enrollment (or in the 6 weeks preceding the first vaccine administration) or planned participation during the present study period in another clinical study investigating a vaccine, drug, medical device, or medical procedure

OTHER EXCLUSIONS For adolescents (6 to 17 YoA) only

• Deprived of freedom by an administrative or court order, or in an emergency setting, or hospitalized involuntarily
• Identified as an Investigator or employee of the Investigator or study center with direct involvement in the proposed study, or identified as an immediate family member (ie, parent, spouse, natural or adopted child) of the Investigator or employee with direct involvement in the proposed study

The above information is not intended to contain all considerations relevant to a patient's 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: Single

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Infants (7 to 11 MoA); Participants will receive 3 intramuscular injections of pneumococcal vaccine with an interval of: 4 to 8 weeks (28 to 56 days) between the 1st dose and the 2nd dose; 8 to 12 weeks (56 to 84 days) between the 2nd dose and the 3rd dose AND age ≥ 12 MoA at 3rd dose	Biological: PCV21; Investigational pneumococcal conjugate vaccine; Biological: 20vPCV; 20-valent pneumococcal conjugate vaccine
Experimental: Toddlers (12 to 23 MoA); Participants will receive 2 intramuscular injections of the pneumococcal vaccine with an interval of 8 to 12 weeks (56 to 84 days) between doses	Biological: PCV21; Investigational pneumococcal conjugate vaccine; Biological: 20vPCV; 20-valent pneumococcal conjugate vaccine
Experimental: Children/adolescent (2 to 5 and 6 to 17 YoA); Participants will receive 1 intramuscular injection of the pneumococcal vaccine	Biological: PCV21; Investigational pneumococcal conjugate vaccine; Biological: 20vPCV; 20-valent pneumococcal conjugate vaccine

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of participants reporting immediate adverse events (AEs)	Unsolicited (spontaneously reported) systemic AEs after each and any injection of a pneumococcal vaccine	Within 30 minutes post-vaccination
Number of participants reporting solicited injection site and solicited systemic reactions		Up to Day 7 post-vaccination
Number of participants reporting unsolicited (spontaneously reported) injection site reactions and unsolicited systemic AEs after each and any injection of a pneumococcal vaccine		Within 30 days after vaccination
Number of participants reporting serious adverse events (SAEs) and adverse events of special interest (AESIs)	SAEs and AESIs are collected throughout the study period	From day 0 to day 517
Number of Infants (7-11 months of age [MoA]) and toddlers (12-23 MoA): with serotype-specific IgG concentrations for all serotypes included in PCV21	Ab (antibody) concentrations for each pneumococcal serotype are measured.	On day 30 after last vaccination
Number of Children (2-5 years of age [YoA]):with serotype specific OPA titers for all serotypes included in PCV21	Serotype specific OPA titers for each pneumococcal serotype are determined.	On day 30
Number of Children (2-5 years of age [YoA]):with serotype specific IgG concentrations for all serotypes included in PCV21	Ab concentrations for each pneumococcal serotype are measured.	On day 30
Number of Children/adolescents (6-17 YoA):with serotype specific OPA titers for all serotypes included in PCV21	Serotype specific OPA titers for each pneumococcal serotype are determined.	On day 30

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of Children/adolescents (≥ 2 YoA) with serotype specific OPA titers for all serotypes included in PCV 21	Serotype specific OPA titers for each pneumococcal serotype are determined.	On day 30
Number of Children/adolescents (≥ 2 YoA): with serotype specific IgG concentrations for all serotypes included in PCV21	Ab concentrations for each pneumococcal serotype are measured.	On day 30
Number of participants (all age groups) with serotype specific IgG concentration ≥ 0.35 μg/mL for all serotypes included in PCV21	Ab concentrations for each pneumococcal serotype are measured.	On day 30 after last vaccination
Number of infants (7-11 MoA) and toddlers(12-23 MoA):with serotype specific OPA titers for all serotypes included in PCV21	Serotype specific OPA titers for each pneumococcal serotype are determined.	On day 30 after last vaccination
Percentage of infants (7-11 MoA) and toddlers(12-23 MoA): with serotype specific OPA titers ≥ LLOQ for all serotypes included in PCV21	Serotype specific OPA titers for each pneumococcal serotype included in the PCV21 formulations are determined. The following threshold values will be considered: ≥ lower limit of quantitation (LLOQ)	On day 30 after last vaccination
Number of Children/adolescents (6-17 YoA):with serotype specific IgG concentrations for all serotypes included in PCV21	Ab concentrations for each pneumococcal serotype are measured.	On day 30

Collaborators and Investigators

• Sponsor: Sanofi Pasteur, a Sanofi Company
• Investigators: Study Director: Clinical Sciences & Operations Study Director, Sanofi

Publications and helpful links

Helpful Links

• Plain Language Results Summary

Study record dates

Study Major Dates

• Study Start (Actual): February 28, 2025
• Primary Completion (Estimated): December 1, 2026
• Study Completion (Estimated): December 1, 2026

Study Registration Dates

• First Submitted: October 10, 2024
• First Submitted That Met QC Criteria: February 17, 2025
• First Posted (Actual): February 20, 2025

Study Record Updates

• Last Update Posted (Estimated): October 6, 2025
• Last Update Submitted That Met QC Criteria: October 3, 2025
• Last Verified: September 1, 2025

More Information

Terms related to this study

• Keywords: Pneumococcal Vaccines; Healthy Participants; Pneumococcal Conjugate Vaccine
• Additional Relevant MeSH Terms: Infections; Gram-Positive Bacterial Infections; Bacterial Infections; Bacterial Infections and Mycoses; Streptococcal Infections; Pneumococcal Infections
• Other Study ID Numbers: PSK00010; U1111-1294-7860 (Other Identifier: WHO ICTRP); 2024-512271-13 (Other Identifier: CTIS)

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
• product manufactured in and exported from the U.S.: No