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of the low dose VAX-31

Phase 2

Pneumococcal Vaccines | Monoclonal antibody | Infectious Disease |Vaxcyte, Inc.|Last Updated: May 15, 2026

Target and mechanism

ModalityMonoclonal antibody

Also known as 0.5 mL of the low dose VAX-31

Success Probability

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Market & Valuation

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Trial Design

RandomizedDouble-BlindACTIVE_CONTROLLEDDMC
Total Trials1
Total Enrollment900

FDA Designations

BREAKTHROUGH_THERAPY

Clinical trial landscape

of the low dose VAX-31 · 1 trial · 1 indication

Phase 2 1
NCT06720038A Clinical Study to Evaluate the Safety, Tolerability, and Immunogenicity of VAX-31 in Healthy InfantsPneumococcal Vaccines
ACTIVE NOT_RECRUITING900 Analytics
PHASE2ACTIVE NOT_RECRUITING
A Clinical Study to Evaluate the Safety, Tolerability, and Immunogenicity of VAX-31 in Healthy Infants
Pneumococcal VaccinesUnlock trial analytics

Study Endpoints

Primary Endpoints

Percentage of subjects with any solicited local injection site adverse events (AE) within 7 days after each vaccination
7 days after each vaccination

Solicited local reactions include erythema, edema, and tenderness at the injection site

Percentage of subjects with any solicited systemic AE within 7 days after each vaccination
7 days after each vaccination

Solicited systemic reactions include fever, irritability, decreased appetite, decreased sleep, and increased sleep

Percentage of subjects with any unsolicited AE within 1 month after each vaccination
1 months after each vaccination

Percentage of subjects with unsolicited AE

Percentage of subjects with any medically attended adverse events (MAAE) within 6 months after last vaccination
6 months after last vaccination

Percentage of subjects with MAAE

Percentage of subjects with any Serious Adverse Events (SAE) within 6 months after last vaccination
6 months after last vaccination

Percentage of subjects with SAE

Percentage of subjects with any new onset of chronic illness (NOCI) within 6 months after last vaccination
6 months after last vaccination

Percentage of subjects with NOCI

Secondary Endpoints

Percentage of subjects achieving a serotype-specific anti-pneumococcal IgG antibody concentration ≥0.35 mcg/mL 1 month after Dose 3
1 month after Dose 3
Serotype-specific IgG antibody geometric mean concentration (GMC) 1 month after Dose 3
1 month after Dose 3
Serotype-specific IgG antibody GMC 1 month after Dose 4
1 month after Dose 4
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Study Design & Arms

AllocationRANDOMIZED
MaskingQUADRUPLE
ModelPARALLEL
PurposePREVENTION

Treatment Arms

ArmTypeDescription
VAX-31 LowEXPERIMENTALParticipants will receive 4 doses of VAX-31 administered as an intramuscular injection at 2, 4, 6, and 12-15 months of age at one of four dose levels.
VAX-31 MidEXPERIMENTALParticipants will receive 4 doses of VAX-31 administered as an intramuscular injection at 2, 4, 6, and 12-15 months of age at one of four dose levels.
VAX-31 HighEXPERIMENTALParticipants will receive 4 doses of VAX-31 administered as an intramuscular injection at 2, 4, 6, and 12-15 months of age at one of four dose levels.
PCV20ACTIVE_COMPARATORParticipants will receive 4 doses of PCV20 administered as an intramuscular injection of the standard dose at 2, 4, 6, and 12-15 months of age.
VAX-31 High-PFSEXPERIMENTALParticipants will receive 4 doses of VAX-31 administered as an intramuscular injection at 2, 4, 6, and 12-15 months of age at one of four dose levels.

Interventions

NameTypeDescription
0.5 mL of the low dose VAX-31BIOLOGICAL31 valent pneumococcal conjugate vaccine
0.5 mL of the mid dose VAX-31BIOLOGICAL31 valent pneumococcal conjugate vaccine
0.5 mL of the high dose VAX-31BIOLOGICAL31 valent pneumococcal conjugate vaccine
0.5 mL dose of PCV20BIOLOGICAL20 valent pneumococcal conjugate vaccine
0.5 mL of the High-PFS dose VAX-31BIOLOGICAL31 valent pneumococcal conjugate vaccine
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Eligibility Criteria

Age Range42 Days to 89 Days
SexALL
Healthy VolunteersYes
Study Sites48

Inclusion Criteria: 1. Healthy male or female infant ≥42 days to ≤89 days. 2. Full-term infant at least 37 weeks gestational age at birth. 3. Afebrile for ≥72 hours with an tympanic or rectal temperature \<38.0°C (\<100.4°F) before receipt of study vaccine.\*Criterion applies to each vaccination. I...

Countries:United StatesPuerto Rico
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Frequently asked questions about of the low dose VAX-31

What is VAX-31 used for?

VAX-31 is an investigational pneumococcal vaccine being studied for use in healthy infants. It is designed to help prevent pneumococcal disease, which is caused by Streptococcus pneumoniae bacteria. The vaccine is currently in Phase 2 clinical development and has not yet been approved by regulatory authorities.

What does VAX-31 target?

VAX-31 is a pneumococcal vaccine, meaning it targets Streptococcus pneumoniae bacteria. The vaccine is intended to elicit an immune response against pneumococcal strains to prevent infections such as pneumonia, bacteremia, and meningitis. It is being evaluated for its safety, tolerability, and immunogenicity in infants.

Who makes VAX-31?

VAX-31 is being developed by Vaxcyte, Inc., a biopharmaceutical company traded on the stock exchange under the ticker symbol PCVX. The company is conducting clinical trials to evaluate the vaccine's safety and effectiveness in preventing pneumococcal disease.

What phase is VAX-31 in?

VAX-31 is currently in Phase 2 clinical development. It is an investigational drug, meaning it has not been approved by the FDA or other regulatory agencies. The vaccine is being studied in a clinical trial to assess its safety, tolerability, and immunogenicity in healthy infants.

What clinical trials is VAX-31 in?

VAX-31 is being evaluated in a Phase 2 clinical trial with the identifier NCT06720038. This study is assessing the safety, tolerability, and immunogenicity of VAX-31 in healthy infants. The trial is active but not recruiting, with an enrollment of 900 participants across the United States and Puerto Rico.

Is VAX-31 the same as 0.5 mL of the low dose VAX-31?

Yes, VAX-31 is also known as 0.5 mL of the low dose VAX-31. This alternative name refers to a specific formulation or dosage of the vaccine being tested in clinical trials. Both names refer to the same investigational pneumococcal vaccine developed by Vaxcyte, Inc.