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VLA15

Phase 3

Lyme Borreliosis | Monoclonal antibody | Infectious Disease |Pfizer, Inc.|Last Updated: Jun 4, 2026

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Trial Design
RandomizedDouble-BlindCONTROLLEDDMC
Total Trials4
Total Enrollment1,650
FDA Designations
No designations recorded
Clinical trial landscape

VLA15 · 7 trials · 2 indications

Phase 3 4Phase 2 3
NCT07500506A Study to Learn About the Safety, Tolerability, and Immunogenicity of a Fifth Dose of 6-Valent OspA-Based Lyme Disease VaccineLyme Disease
RECRUITING1,712 Analytics
NCT07226882A Study to Learn About Different Dosing Schedules of a Lyme Disease Vaccine in Healthy AdultsLyme Borreliosis
ACTIVE NOT_RECRUITING207 Analytics
NCT05634811Safety Study of a Vaccine to Help Protect Against Lyme Disease in Healthy ChildrenLyme Disease
COMPLETED3,547 Analytics
NCT05477524An Efficacy, Safety, Tolerability, Immunogenicity, and Lot-Consistency Clinical Trial of a 6-Valent OspA-Based Lyme Disease Vaccine (VLA15)Lyme Disease
COMPLETED12,546 Analytics
PHASE3RECRUITING
A Study to Learn About the Safety, Tolerability, and Immunogenicity of a Fifth Dose of 6-Valent OspA-Based Lyme Disease Vaccine
Lyme DiseaseUnlock trial analytics
PHASE3ACTIVE NOT_RECRUITING
A Study to Learn About Different Dosing Schedules of a Lyme Disease Vaccine in Healthy Adults
Lyme BorreliosisUnlock trial analytics
PHASE3COMPLETED
Safety Study of a Vaccine to Help Protect Against Lyme Disease in Healthy Children
Lyme DiseaseUnlock trial analytics
PHASE3COMPLETED
An Efficacy, Safety, Tolerability, Immunogenicity, and Lot-Consistency Clinical Trial of a 6-Valent OspA-Based Lyme Disease Vaccine (VLA15)
Lyme DiseaseUnlock trial analytics
Study Endpoints
Primary Endpoints
Percentage of participants reporting prespecified local reactions
Within 7 days following each study intervention administration
Percentage of participants reporting prespecified systemic events
Within 7 days following each study intervention administration
Percentage of participants reporting adverse events (AEs)
Through 1 month following study intervention administration
Percentage of participants reporting newly diagnosed chronic medical conditions (NDCMCs)
Through study completion, up to approximately 12 months.
Percentage of participants reporting serious adverse events (SAEs)
Through study completion, up to approximately 12 months.
Geometric mean ratio (GMR) of anti-OspA IgG concentrations for each serotype (ST1-ST6)
At 1 month after completion of Dose 5

Objective to determine non-inferiority of Dose 5 compared to Dose 4 in all participants when there is a 1 year gap between Dose 4 and Dose 5.

Sero-response of anti-OspA IgG concentrations for each serotype (ST1-ST6).
At 1 month after completion of Dose 5

Difference in seroresponse rate between 1 month after Dose 5 and 1 month after Dose 4 for each serotype in all participants ≥7 years of age who received a fifth dose of VLA15 1 year after their fourth dose of VLA15.

Geometric Mean Concentration (GMC) of Anti-Outer Surface Protein A (OspA) Immunoglobulin G (IgG)
At 1 month after the fourth VLA15 dose
Geometric Mean Fold Rise (GMFR) of Anti-Outer Surface Protein A (OspA) Immunoglobulin G (IgG) Concentrations
Before the first dose to 1 month after the fourth VLA15 dose
Sero-Response Rate Based on Anti-Outer Surface Protein A (OspA) Immunoglobulin G (IgG) Concentrations.
Before the first dose to 1 month after the fourth VLA15 dose
Percentage of Participants With Local Reactions For Each Group
Within 7 days after each vaccination
Percentage of Participants With Systemic Events For Each Group
Within 7 days after each vaccination
Percentage of Participants With Adverse Events (AEs) For Each Group
Within 1 month after each vaccination
Percentage of Participants With Serious Adverse Events (SAEs) For Each Group
From the time the participant provides informed consent up to approximately 6 months after the last vaccination
Percentage of Participants With Newly Diagnosed Chronic Medical Conditions (NDCMCs) For Each Group
From the time the participant provides informed consent up to approximately 6 months after the last vaccination
Percentage of Participants With at Least 1 Local Reaction of Any Grade for up to 7 Days Following Study Vaccination 1
From Day 1 through Day 7 after Study Vaccination 1 (Vaccination on Day 1, Month 0)

Local reactions included pain at injection site, redness and swelling and were recorded by participants in the electronic dairy (e-diary) or by investigators in case report form (CRF) after vaccination. Local reactions were graded per the 'Local Reaction Grading Scale' per protocol based on Center for Biologics Evaluation and Research (CBER) toxicity guidelines. Percentage of participants with at least 1 local reaction of any grade were reported in this outcome measure.

Percentage of Participants With at Least 1 Local Reaction of Any Grade for up to 7 Days Following Study Vaccination 2
From Day 1 through Day 7 after Study Vaccination 2 (Vaccination on Day 1, Month 2)

Local reactions included pain at injection site, redness and swelling and were recorded by participants in the e-diary or by investigators in CRF after vaccination. Local reactions were graded per the 'Local Reaction Grading Scale' per protocol based on CBER toxicity guidelines. Percentage of participants with at least 1 local reaction of any grade were reported in this outcome measure.

Percentage of Participants With at Least 1 Local Reaction of Any Grade for up to 7 Days Following Study Vaccination 3
From Day 1 through Day 7 after Study Vaccination 3 (Vaccination on Day 1, Month 6)

Local reactions included pain at injection site, redness and swelling and were recorded by participants in the e-diary or by investigators in CRF after vaccination. Local reactions were graded per the 'Local Reaction Grading Scale' per protocol based on CBER toxicity guidelines. Percentage of participants with at least 1 local reaction of any grade were reported in this outcome measure.

Percentage of Participants With at Least 1 Local Reaction of Any Grade for up to 7 Days Following Study Vaccination 4 (Booster Dose)
From Day 1 through Day 7 after Study Vaccination 4 (Vaccination on Day 1, Month 18)

Local reactions included pain at injection site, redness and swelling and were recorded by participants in the e-diary or by investigators in CRF after vaccination. Local reactions were graded per the 'Local Reaction Grading Scale' per protocol based on CBER toxicity guidelines. Percentage of participants with at least 1 local reaction of any grade were reported in this outcome measure.

Percentage of Participants With at Least 1 Local Reaction of Any Grade for up to 7 Days After Any Study Vaccination
From Day 1 through Day 7 after any study vaccination

Local reactions included pain at injection site, redness and swelling and were recorded by participants in the e-diary or by investigators in CRF after vaccination. Local reactions were graded per the 'Local Reaction Grading Scale' per protocol based on CBER toxicity guidelines. Percentage of participants with at least 1 local reaction of any grade were reported in this outcome measure.

Percentage of Participants With at Least 1 Systemic Event of Any Grade for up to 7 Days Following Study Vaccination 1
From Day 1 through Day 7 after Study Vaccination 1 (Vaccination on Day 1, Month 0)

Systemic events included fever, fatigue, headache, muscle pain and joint pain and were recorded by participants in the e-diary or by investigators in CRF after vaccination. Systemic events were graded per the 'Systemic Events Grading Scale' per protocol based on CBER toxicity guidelines. Percentage of participants with at least 1 systemic event of any grade were reported in this outcome measure.

Percentage of Participants With at Least 1 Systemic Event of Any Grade for up to 7 Days Following Study Vaccination 2
From Day 1 through Day 7 after Study Vaccination 2 (Vaccination on Day 1, Month 2)

Systemic events included fever, fatigue, headache, muscle pain and joint pain and were recorded by participants in the e-diary or by investigators in CRF after vaccination. Systemic events were graded per the 'Systemic Events Grading Scale' per protocol based on CBER toxicity guidelines. Percentage of participants with at least 1 systemic event of any grade were reported in this outcome measure.

Percentage of Participants With at Least 1 Systemic Event of Any Grade for up to 7 Days Following Study Vaccination 3
From Day 1 through Day 7 after Study Vaccination 3 (Vaccination on Day 1, Month 6)

Systemic events included fever, fatigue, headache, muscle pain and joint pain and were recorded by participants in the e-diary or by investigators in CRF after vaccination. Systemic events were graded per the 'Systemic Events Grading Scale' per protocol based on CBER toxicity guidelines. Percentage of participants with at least 1 systemic event of any grade were reported in this outcome measure.

Percentage of Participants With at Least 1 Systemic Event of Any Grade for up to 7 Days Following Study Vaccination 4 (Booster Dose)
From Day 1 through Day 7 after Study Vaccination 4 (Vaccination on Day 1, Month 18)

Systemic events included fever, fatigue, headache, muscle pain and joint pain and were recorded by participants in the e-diary or by investigators in CRF after vaccination. Systemic events were graded per the 'Systemic Events Grading Scale' per protocol based on CBER toxicity guidelines. Percentage of participants with at least 1 systemic event of any grade were reported in this outcome measure.

Percentage of Participants With at Least 1 Systemic Event of Any Grade for up to 7 Days After Any Study Vaccination
From Day 1 through Day 7 after any study vaccination

Systemic events included fever, fatigue, headache, muscle pain and joint pain and were recorded by participants in the e-diary or by investigators in CRF after vaccination. Systemic events were graded per the 'Systemic Events Grading Scale' per protocol based on CBER toxicity guidelines. Percentage of participants with at least 1 systemic event of any grade were reported in this outcome measure.

Percentage of Participants With AEs Through 1 Month Following Study Vaccination 1
From Day 1 through 1 Month after Study Vaccination 1 (Vaccination on Day 1, Month 0)

An AE was any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. Only AEs collected by non-systematic assessment (excluding local reactions and systematic events) after dose 1 were included in this outcome measure. AEs included both serious AEs (SAEs) and non-SAEs.

Percentage of Participants With AEs Through 1 Month Following Study Vaccination 2
From Day 1 through 1 Month after Study Vaccination 2 (Vaccination on Day 1, Month 2)

An AE was any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. Only AEs collected by non-systematic assessment (excluding local reactions and systematic events) after dose 2 were included in this outcome measure. AEs included both SAEs and non-SAEs.

Percentage of Participants With AEs Through 1 Month Following Study Vaccination 3
From Day 1 through 1 Month after Study Vaccination 3 (Vaccination on Day 1, Month 6)

An AE was any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. Only AEs collected by non-systematic assessment (excluding local reactions and systematic events) after dose 3 were included in this outcome measure. AEs included both SAEs and non-SAEs.

Percentage of Participants With AEs Through 1 Month Following Study Vaccination 4 (Booster Dose)
From Day 1 through 1 Month after Study Vaccination 4 (Vaccination on Day 1, Month 18)

An AE was any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. Only AEs collected by non-systematic assessment (excluding local reactions and systematic events) after dose 4 were included in this outcome measure. AEs included both SAEs and non-SAEs.

Percentage of Participants With AEs Through 1 Month Following Any Study Vaccination
From Day 1 through 1 Month after any study vaccination

An AE was any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. Only AEs collected by non-systematic assessment (excluding local reactions and systematic events) after any dose were included in this outcome measure.

Percentage of Participants With Newly Diagnosed Chronic Medical Condition (NDCMCs) Throughout the Study
Throughout the study (from study vaccination 1 through 6 months post study Vaccination 4 [Booster dose]: maximum up to 24 months)

An NDCMC was defined as a disease or medical condition, not previously identified, that was expected to be persistent or was otherwise long-lasting in its effects. NDCMCs included conditions that were undiagnosed prior to study entry (diagnosed while in the study and confirmed not to be a preexisting condition) and that were not considered temporary conditions based upon the expected natural history of the condition. An NDCMC was not reported on AE CRF.

Percentage of Participants With Serious Adverse Events (SAEs) Throughout the Study
Throughout the study (from study vaccination 1 through 6 months post study Vaccination 4 [Booster dose]: maximum up to 24 months)

An SAE was defined as any untoward medical occurrence that, at any dose, met one or more of the following criteria: resulted in death, was life-threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, was a congenital anomaly/birth defect, any other important medical event.

Relative incidence rate reduction of confirmed Lyme disease cases in the VLA15 group compared to the placebo group
Beginning 1 month after receiving the booster dose (28 days after receiving the booster dose through the end of the Lyme disease season following the booster dose (end of October)).

A confirmed case of Lyme disease, caused by B burgdorferi sensu lato, is defined as a clinically suspected case of Lyme disease that is confirmed by PCR, culture, microbial cell-free B burgdorferi-specific DNA sequencing, or serological antiborrelial antibody assay, and finally assessed and confirmed to be a case by the independent Adjudication Committee

Percentage of participants reporting local reactions
Within 7 days following each study intervention administration
Percentage of participants reporting systemic events
Within 7 days following each study intervention administration
Geometric mean ratio (GMR) of anti-OspA titers for each serotype (ST1-ST6) for Lot 1 to Lot 2
At 1 month after completion of the primary series and the booster dose
Geometric mean ratio (GMR) of anti-OspA titers for each serotype (ST1-ST6) for Lot 1 to Lot 3
At 1 month after completion of the primary series and the booster dose
Geometric mean ratio (GMR) of anti-OspA titers for each serotype (ST1-ST6) for Lot 2 to Lot 3
At 1 month after completion of the primary series and the booster dose
Geometric mean ratio (GMR) of anti-OspA titers for each serotype (ST1-ST6)
At 1 month after completion of the booster dose

Immunobridging objective to determine non-inferiority between 5-17 year old and 18-44 year old participant strata using GMRs 1 month after completion of booster dose.

Sero-response of anti-OspA IgG concentrations for each serotype (ST1-ST6)
At 1 month after completion of the booster dose

Immunobridging objective to determine non-inferiority between 5-17 year old and 18-44 year old participant strata using difference in seroresponse rates 1 month after completion of booster dose.

Percentage of Participants With Solicited Local and Solicited Systemic Adverse Events (AEs) Within 7 Days After Vaccination 1
From Day 1 to Day 7 after vaccination 1 at Month 0

Participants or their legal guardians were required to record any solicited local and systemic adverse events in the electronic diary. Solicited symptoms were pre-defined symptoms which were collected via an electronic diary. Solicited local AEs included pain, tenderness, erythema (redness), swelling and induration (hardening). Solicited systemic AEs included headache, muscle pain, joint pain, nausea, vomiting, fatigue and fever. Two-sided 95% confidence intervals were calculated according to Altman method.

Percentage of Participants With Solicited Local and Solicited Systemic AEs Within 7 Days After Vaccination 2
From Day 1 to Day 7 after vaccination 2 at Month 2

Participants or their legal guardians were required to record any solicited local and systemic adverse events in the electronic diary. Solicited symptoms were pre-defined symptoms which were collected via an electronic diary. Solicited local AEs included pain, tenderness, erythema (redness), swelling and induration (hardening). Solicited systemic AEs included headache, muscle pain, joint pain, nausea, vomiting, fatigue and fever. Two-sided 95% confidence intervals were calculated according to Altman method.

Percentage of Participants With Solicited Local and Solicited Systemic AEs Within 7 Days After Vaccination 3
From Day 1 to Day 7 after vaccination 3 at Month 6

Participants or their legal guardians were required to record any solicited local and systemic adverse events in the electronic diary. Solicited symptoms were pre-defined symptoms which were collected via an electronic diary. Solicited local AEs included pain, tenderness, erythema (redness), swelling and induration (hardening). Solicited systemic AEs included headache, muscle pain, joint pain, nausea, vomiting, fatigue and fever. Two-sided 95% confidence intervals were calculated according to Altman method.

Percentage of Participants With Solicited Local and Solicited Systemic AEs Within 7 Days After Any Vaccination During the Main Study Phase
From Day 1 to Day 7 after vaccination 1, 2 or 3 at Month 0, 2 and 6 respectively

Participants or their legal guardians were required to record any solicited local and systemic adverse events in the electronic diary. Solicited symptoms were pre-defined symptoms which were collected via an electronic diary. Solicited local AEs included pain, tenderness, erythema (redness), swelling and induration (hardening). Solicited systemic AEs included headache, muscle pain, joint pain, nausea, vomiting, fatigue and fever. Two-sided 95% confidence intervals were calculated according to Altman method.

Geometric Mean Titers (GMTs) for Immunoglobulin G (IgG) Against Each Outer Surface Protein A (OspA) Serotype (ST1 to ST6) at Day 208 During the Main Study Phase
Day 208 (Month 7)

GMTs for IgG against each OspA serotype ST1 to ST6, determined by an IgG binding assay at Day 208 is presented in this outcome measure.

GMTs for IgG Against Each OspA Serotype
Day 208 (Month 7)

Geometric Mean Titers (GMTs) for Immunoglobulin G (IgG) against each Outer Surface Protein A (OspA) serotype ST1 to ST6, determined by Enzyme-Linked Immunosorbent Assay (ELISA) at Day 208 (Month 7)

GMTs (Geometric Mean Titers) for IgG (Immunoglobulin G) Against Each OspA (Outer Surface Protein A) Serotype ST1 to ST6
at Day 85 / Month 3

GMTs (Geometric Mean Titers) for IgG (Immunoglobulin G) against each OspA (Outer Surface Protein A) serotype ST1 to ST6, determined by ELISA at Day 85. GMTs are calculated based on the number of subjects with non-missing results.

Secondary Endpoints
Geometric mean ratio (GMR) of anti-OspA IgG concentrations for each serotype (ST1-ST6)
At 1 month after completion of Dose 5
Geometric mean fold rise (GMFR) of anti-OspA IgG concentrations for each serotype (ST1-ST6)
At just prior to Dose 5 and 1 month after completion of Dose 5
Geometric mean concentration (GMC) of anti-OspA IgG concentrations for each serotype (ST1-ST6)
At 1 month after completion of Dose 5
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Study Design & Arms
AllocationRANDOMIZED
MaskingTRIPLE
ModelPARALLEL
PurposePREVENTION
Treatment Arms
ArmTypeDescription
VLA15-1AEXPERIMENTALParticipants will receive a single injection in the muscle (IM) of VLA15 at Visits 1, two years after their 4th dose of VLA15
VLA15-1BPLACEBO_COMPARATORParticipants will receive a single injection in the muscle (IM) of Saline at Visits 1, two years after their 4th dose of VLA15
VLA15-2AEXPERIMENTALParticipants will receive a single injection in the muscle (IM) of VLA15 at Visits 1, one year after their 4th dose of VLA15
VLA15-2BPLACEBO_COMPARATORParticipants will receive a single injection in the muscle (IM) of saline at Visits 1, one year after their 4th dose of VLA15
Group 1EXPERIMENTALParticipants will receive 4 doses of VLA15 and 1 dose of placebo injection at different visits. Placebo will be given at Visit 3. Injections will be given as intramuscular shots.
Group 2EXPERIMENTALParticipants will receive 4 doses of VLA15 and 1 dose of placebo injection at different visits. Placebo will be given at Visit 5. Injections will be given as intramuscular shots.
Group 3EXPERIMENTALParticipants will receive 4 doses of VLA15 and 1 dose of placebo injection at different visits. Placebo will be given at Visit 7. Injections will be given as intramuscular shots.
Group 4EXPERIMENTALParticipants will receive 4 doses of VLA15 and 1 dose of placebo injection at different visits. Placebo will be given at Visit 9. Injections will be given as intramuscular shots.
VLA15EXPERIMENTALParticipants will receive 6-valent OspA-based Lyme disease vaccine (VLA15).
Normal Saline (Placebo)PLACEBO_COMPARATORParticipants will receive 0.9% sodium chloride solution for injection
VLA15 Lot 1 (3-dose primary vaccination series and booster dose)EXPERIMENTALShot in the deltoid muscle (preferable in the nondominant arm)
VLA15 Lot 2 (3-dose primary vaccination series and booster dose)EXPERIMENTALShot in the deltoid muscle (preferable in the nondominant arm)
VLA15 Lot 3 (3-dose primary vaccination series and booster dose)EXPERIMENTALShot in the deltoid muscle (preferable in the nondominant arm)
Placebo (3-dose primary vaccination series and booster dose)PLACEBO_COMPARATORShot in the deltoid muscle (preferable in the nondominant arm)
Part A+B - Group 1EXPERIMENTALPart A: VLA15 at Month 0, 2 and 6 Part B: VLA15 at Month 18, 30 and 42
Part A+B - Group 2EXPERIMENTALPart A: VLA15 at Month 0 and 6, placebo at Month 2 Part B: VLA15 at Month 18, 30 and 42
Part A+B - Group 3PLACEBO_COMPARATORPart A: Placebo at Month 0, 2 and 6 Part B: Placebo at Month 18, 30 and 42
VLA15 with Alum lower doseEXPERIMENTALMain Study Phase: VLA15 with Alum lower dose - Booster Phase: arm discontinued
VLA15 with Alum higher doseEXPERIMENTALMain Study Phase: VLA15 with Alum higher dose - Booster Phase: VLA15 higher dose or placebo
PlaceboPLACEBO_COMPARATORMain Study Phase: placebo - Booster Phase: arm discontinued
VLA15 low doseACTIVE_COMPARATORVLA15 low dose with Alum.
VLA15 medium doseACTIVE_COMPARATORVLA15 medium dose with Alum.
VLA15 high doseACTIVE_COMPARATORVLA15 high dose with Alum.
Interventions
NameTypeDescription
VLA15BIOLOGICALVLA15 injection IM
PlaceboBIOLOGICALSaline Injection
Normal SalineOTHER0.9% sodium chloride solution for injection
SalineOTHERShot in the deltoid muscle (preferable in the nondominant arm)
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Eligibility Criteria
Age Range7 Years to N/A
SexALL
Healthy VolunteersYes
Study Sites22

Inclusion Criteria: * Participants who are healthy as determined by medical history and clinical judgment. * Participants willing and able to comply with all scheduled visits, IP receipt, and other procedures throughout the study. * Able to provide Informed Consent. * Participants must have receive...

Countries:United StatesCanadaFinlandGermanyNetherlandsPolandSwedenBelgium
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Recent Changes (Last 90 Days)
MEDIUMJul 5, 2026NCT05477524TRIAL_REMOVED: changed
MEDIUMJul 5, 2026NCT05477524TRIAL_REMOVED: changed
MEDIUMJul 5, 2026NCT05477524TRIAL_REMOVED: changed
MEDIUMJun 19, 2026NCT04801420TRIAL_REMOVED: changed
MEDIUMJun 19, 2026NCT04801420TRIAL_REMOVED: changed
MEDIUMJun 19, 2026NCT04801420TRIAL_REMOVED: changed
MEDIUMJun 7, 2026NCT05634811TRIAL_REMOVED: changed
MEDIUMJun 7, 2026NCT05634811TRIAL_REMOVED: changed
MEDIUMJun 7, 2026NCT05634811TRIAL_REMOVED: changed
MEDIUMJun 7, 2026NCT05634811TRIAL_REMOVED: changed
MEDIUMJun 7, 2026NCT05634811TRIAL_REMOVED: changed
MEDIUMJun 7, 2026NCT05634811TRIAL_REMOVED: changed
LOWJun 4, 2026NCT05477524Completion: 2026-02-06 → 2026-01-07
LOWJun 4, 2026NCT05477524Completion: 2026-02-06 → 2026-01-07
LOWJun 4, 2026NCT05477524Completion: 2026-02-06 → 2026-01-07
LOWJun 4, 2026NCT05477524Completion: 2026-02-06 → 2026-01-07
MEDIUMMay 26, 2026NCT07226882Status: RECRUITING → ACTIVE_NOT_RECRUITING
HIGHMay 26, 2026NCT05477524Status: ACTIVE_NOT_RECRUITING → COMPLETED