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PCV21

Phase 3

Pneumococcal Infections | Monoclonal antibody | Infectious Disease |Sanofi|Last Updated: Apr 15, 2026

Target and mechanism

ModalityMonoclonal antibody

Also known as PCV21 vaccine

Success Probability

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Market & Valuation

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Trial Design

RandomizedCONTROLLEDDMC
Total Trials1
Total Enrollment1,268

FDA Designations

No designations recorded

Clinical trial landscape

PCV21 · 2 trials · 2 indications

Phase 3 2
NCT07247188Study of a Single Dose of a 21-valent Pneumococcal Conjugate Vaccine in Children and Adolescents With Sickle Cell DiseaseSickle Cell Disease
RECRUITING100 Analytics
NCT06838000Study of the Safety and Immunogenicity of Catch-up Vaccination With a 21-valent Pneumococcal Conjugate Vaccine (PCV21) in Healthy Infants, Toddlers, Children, and AdolescentsPneumococcal Infections
ACTIVE NOT_RECRUITING1,268 Analytics
PHASE3RECRUITING
Study of a Single Dose of a 21-valent Pneumococcal Conjugate Vaccine in Children and Adolescents With Sickle Cell Disease
Sickle Cell DiseaseUnlock trial analytics
PHASE3ACTIVE NOT_RECRUITING
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
Pneumococcal InfectionsUnlock trial analytics

Study Endpoints

Primary Endpoints

Number of participants reporting immediate adverse events (AEs)
Within 30 minutes post-vaccination

Unsolicited (spontaneously reported) systemic AEs after injection of a pneumococcal vaccine

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 injection of a pneumococcal vaccine
Within 30 days post-vaccination
Number of participants reporting serious adverse events (SAEs) and adverse events of special interest (AESIs)
From day 0 to day 181

SAEs and AESIs are collected throughout the study period

Number of participants with serotype-specific immunoglobulin G (IgG) concentrations for all serotypes included in PCV21
On day 30 post-vaccination

Ab (antibody) concentrations for each pneumococcal serotype measured by electro-chemiluminescence (ECL) assay

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 Infants (7-11 months of age [MoA]) and toddlers (12-23 MoA): with serotype-specific IgG concentrations for all serotypes included in PCV21
On day 30 after last vaccination

Ab (antibody) concentrations for each pneumococcal serotype are measured.

Number of Children (2-5 years of age [YoA]):with serotype specific OPA titers for all serotypes included in PCV21
On day 30

Serotype specific OPA titers for each pneumococcal serotype are determined.

Number of Children (2-5 years of age [YoA]):with serotype specific IgG concentrations for all serotypes included in PCV21
On day 30

Ab concentrations for each pneumococcal serotype are measured.

Number of Children/adolescents (6-17 YoA):with serotype specific OPA titers for all serotypes included in PCV21
On day 30

Serotype specific OPA titers for each pneumococcal serotype are determined.

Secondary Endpoints

Number of participants with serotype-specific IgG concentrations for all serotypes included in PCV21
Pre-vaccination and at 30 days post-vaccination
Number of participants with serotype specific opsonophagocytic activity (OPA) titers for all serotypes included in PCV21
On day 30
Number of Children/adolescents (≥ 2 YoA) with serotype specific OPA titers for all serotypes included in PCV 21
On day 30
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Study Design & Arms

AllocationRANDOMIZED
MaskingSINGLE
ModelPARALLEL
PurposePREVENTION

Treatment Arms

ArmTypeDescription
Investigated Vaccine: PCV21EXPERIMENTALParticipants will receive 1 intramuscular injection of the pneumococcal vaccine
Comparator Vaccine: 20vPCVACTIVE_COMPARATORParticipants will receive 1 intramuscular injection of the pneumococcal vaccine
Infants (7 to 11 MoA)EXPERIMENTALParticipants 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
Toddlers (12 to 23 MoA)EXPERIMENTALParticipants will receive 2 intramuscular injections of the pneumococcal vaccine with an interval of 8 to 12 weeks (56 to 84 days) between doses
Children/adolescent (2 to 5 and 6 to 17 YoA)EXPERIMENTALParticipants will receive 1 intramuscular injection of the pneumococcal vaccine

Interventions

NameTypeDescription
PCV21BIOLOGICALInvestigational pneumococcal conjugate vaccine
20vPCVBIOLOGICAL20-valent pneumococcal conjugate vaccine
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Eligibility Criteria

Age Range2 Years to 17 Years
SexALL
Healthy VolunteersNo
Study Sites7

Inclusion Criteria: AGE * Aged 2 to 17 years on the day of inclusion. TYPE OF PARTICIPANT AND DISEASE CHARACTERISTICS * Participants who have a documented diagnosis of sickle cell disease (SCD) in their medical record. SEX, CONTRACEPTIVE/BARRIER METHOD AND PREGNANCY TESTING REQUIREMENTS * A pa...

Countries:United StatesDominican RepublicEstoniaPolandThailand
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Frequently asked questions about PCV21

What is PCV21 used for?

PCV21 is an investigational 21-valent pneumococcal conjugate vaccine being studied for pneumococcal immunization and prevention of pneumococcal infections. It is also being evaluated in the context of sickle cell disease. The vaccine is designed for use in infants, toddlers, children, and adolescents, with clinical trials enrolling healthy participants from approximately 2 months of age.

Who makes PCV21?

PCV21 is being developed by Sanofi, a company listed on the stock exchange under the ticker symbol SNY. Sanofi is conducting Phase 3 clinical trials to evaluate the vaccine's safety and immunogenicity in various age groups, from infants to adolescents.

What phase is PCV21 in?

PCV21 is currently in Phase 3 clinical development. It is an investigational vaccine, meaning it has not yet been approved by regulatory authorities. Sanofi is conducting multiple Phase 3 trials to assess the vaccine's safety and immunogenicity in healthy infants, toddlers, children, and adolescents.

What clinical trials is PCV21 in?

PCV21 is being studied in several Phase 3 trials, including NCT06824181, NCT06824194, NCT06838000, and NCT06975878. These trials evaluate mixed vaccination schedules, safety, and catch-up vaccination in healthy participants from about 2 months of age, with enrollment ranging from 580 to 2,360 participants across multiple countries.

Is PCV21 the same as PCV21 vaccine?

Yes, PCV21 and PCV21 vaccine refer to the same investigational pneumococcal conjugate vaccine being developed by Sanofi. The vaccine is currently in Phase 3 clinical trials for pneumococcal immunization and prevention of pneumococcal infections in infants, children, and adolescents.

How does PCV21 work?

PCV21 is a 21-valent pneumococcal conjugate vaccine, meaning it is designed to target 21 types of pneumococcal bacteria. As a conjugate vaccine, it links pneumococcal polysaccharides to a carrier protein to enhance the immune response, helping the body produce antibodies against these bacterial strains to prevent pneumococcal infections.