An Efficacy, Safety, Tolerability, Immunogenicity, and Lot-Consistency Clinical Trial of a 6-Valent OspA-Based Lyme Disease Vaccine (VLA15) (VALOR)
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ClinicalTrials.gov Identifier: NCT05477524 |
Recruitment Status :
Recruiting
First Posted : July 28, 2022
Last Update Posted : March 21, 2023
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The main purpose of this clinical study is to evaluate a 6-valent OspA-based Lyme disease vaccine (VLA15) for prevention of Lyme disease within North America and Europe. Approximately 18,000 healthy participants 5 years and older will be recruited from areas with high levels of endemic Lyme disease to receive VLA15 or placebo (an inactive substance consisting of saltwater). Each participant will have about a 50% chance of receiving VLA15 and about a 50% chance of receiving placebo. A subset of participants will receive VLA15 from 3 different lots or placebo (1:1:1:3 ratio) to assess lot equivalence.
Participants will receive a 3-dose primary vaccination series at about 0, 2, and 5 to 9 months and then receive a booster dose about 12 months later. Vaccination of participants will occur at a time of year such that the primary series is completed before the peak Lyme disease season followed by a booster dose just prior to the beginning of the second Lyme disease season.
Comparison will be made between the Lyme disease cases of people receiving the study vaccine to those of the people who are not. This will help us determine if the study vaccine is safe and effective.
If enrolled, participants will need to visit the research site at least 7 times during the study. There will also be at least 1 telephone contact. It is expected that each participant will take part in this study for up to about 2 and a half years.
Condition or disease | Intervention/treatment | Phase |
---|---|---|
Lyme Disease | Biological: VLA15 Other: Saline | Phase 3 |
Study Type : | Interventional (Clinical Trial) |
Estimated Enrollment : | 18000 participants |
Allocation: | Randomized |
Intervention Model: | Parallel Assignment |
Masking: | Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor) |
Primary Purpose: | Prevention |
Official Title: | A Phase 3, Multicenter, Placebo-Controlled, Randomized, Observer-Blinded Trial to Evaluate the Efficacy, Safety, Tolerability, Immunogenicity, and Lot Consistency of a 6-Valent OspA-Based Lyme Disease Vaccine in Healthy Participants ≥5 Years of Age |
Actual Study Start Date : | August 4, 2022 |
Estimated Primary Completion Date : | December 31, 2025 |
Estimated Study Completion Date : | December 31, 2025 |

Arm | Intervention/treatment |
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Experimental: VLA15 Lot 1 (3-dose primary vaccination series and booster dose)
Shot in the deltoid muscle (preferable in the nondominant arm)
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Biological: VLA15
Shot in the deltoid muscle (preferable in the nondominant arm) |
Experimental: VLA15 Lot 2 (3-dose primary vaccination series and booster dose)
Shot in the deltoid muscle (preferable in the nondominant arm)
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Biological: VLA15
Shot in the deltoid muscle (preferable in the nondominant arm) |
Experimental: VLA15 Lot 3 (3-dose primary vaccination series and booster dose)
Shot in the deltoid muscle (preferable in the nondominant arm)
|
Biological: VLA15
Shot in the deltoid muscle (preferable in the nondominant arm) |
Placebo Comparator: Placebo (3-dose primary vaccination series and booster dose)
Shot in the deltoid muscle (preferable in the nondominant arm)
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Other: Saline
Shot in the deltoid muscle (preferable in the nondominant arm) |
- Relative risk reduction of confirmed Lyme disease cases in the VLA15 group compared to the placebo group [ Time Frame: In the Lyme disease season beginning 1 month after completing the primary series (28 days after completion of the primary series until 31 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 Endpoint Adjudication Committee
- Relative risk reduction of confirmed Lyme disease cases in the VLA15 group compared to the placebo group [ Time Frame: In the Lyme disease season beginning 1 month after receiving the booster dose (28 days after completion of the booster dose until 31 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 Endpoint Adjudication Committee
- Percentage of participants reporting prompted local reactions [ Time Frame: Within 7 days following each study intervention administration ]
- Percentage of participants reporting prompted systemic events [ Time Frame: Within 7 days following each study intervention administration ]
- Percentage of participants reporting adverse events (AEs) [ Time Frame: Through 1 month following each study intervention administration ]
- Percentage of participants reporting newly diagnosed chronic medical conditions (NDCMCs) [ Time Frame: Through study completion, up to approximately 30 months. ]
- Percentage of participants reporting serious adverse events (SAEs) [ Time Frame: Through study completion, up to approximately 30 months. ]
- Geometric mean ratio (GMR) of anti-OspA titers for each serotype (ST1-ST6) for Lot 1 to Lot 2 [ Time Frame: At 1 month after completion of the primary series ]
- Geometric mean ratio (GMR) of anti-OspA titers for each serotype (ST1-ST6) for Lot 1 to Lot 3 [ Time Frame: At 1 month after completion of the primary series ]
- Geometric mean ratio (GMR) of anti-OspA titers for each serotype (ST1-ST6) for Lot 2 to Lot 3 [ Time Frame: At 1 month after completion of the primary series ]
- Relative risk reduction of Lyme disease-specific seroconversion in otherwise-undiagnosed Lyme disease cases in the VLA15 group compared to the placebo group [ Time Frame: In the Lyme disease season beginning 1 month after completing the primary series (28 days after completion of the primary series until 31 October) ]Nonvaccine-antigen seroconversion as measured at the central laboratory
- Relative risk reduction of Lyme disease-specific seroconversion in otherwise-undiagnosed Lyme disease cases in the VLA15 group compared to the placebo group [ Time Frame: In the Lyme disease season beginning 1 month after receiving the booster dose (28 days after completion of the booster dose until 31 October) ]Nonvaccine-antigen seroconversion as measured at the central laboratory
- Vaccine efficacy among participants enrolled from North American sites [ Time Frame: In the Lyme disease season beginning 1 month after completing the primary series (28 days after completion of the primary series until 31 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 Endpoint Adjudication Committee
- Vaccine efficacy among participants enrolled from European sites [ Time Frame: In the Lyme disease season beginning 1 month after completing the primary series (28 days after completion of the primary series until 31 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 Endpoint Adjudication Committee
- Vaccine efficacy among participants enrolled from North American sites [ Time Frame: In the Lyme disease season beginning 1 month after receiving the booster dose (28 days after completion of the booster dose until 31 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 Endpoint Adjudication Committee
- Vaccine efficacy among participants enrolled from European sites [ Time Frame: In the Lyme disease season beginning 1 month after receiving the booster dose (28 days after completion of the booster dose until 31 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 Endpoint Adjudication Committee

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.
Ages Eligible for Study: | 5 Years and older (Child, Adult, Older Adult) |
Sexes Eligible for Study: | All |
Accepts Healthy Volunteers: | Yes |
Key Inclusion Criteria:
- Participants who reside in areas with endemic Lyme disease and who lead lifestyles that put them at increased risk for Lyme disease. For example, this could include, but not be limited to:
- Individuals who work in B burgdorferi-infected/tick-infested areas, especially those with occupations that may be associated with higher risk of exposure, such as landscaping, forestry, and wildlife and parks management.
- Individuals who pursue recreational activities such as hiking, camping, fishing, hunting, jogging, or gardening in such areas.
- Individuals who live on land plots with tree lines and come into contact with these trees regularly.
- Individuals who have dogs that regularly are outdoors and frequently return with attached ticks.
- Individuals who participate in activities in areas with tall grass, smaller wooded areas beside forests, open fields, lakesides, and riversides.
Key Exclusion Criteria:
- Any diagnosis of Lyme disease within the past 3 months.
- Any history of Lyme carditis, neuroborreliosis, or arthritis, regardless of when diagnosed.
- Known tick bite within the past 4 weeks.
- Newly developed or unstable underlying conditions that may interfere with the assessment of Lyme disease, including but not limited to chronic arthralgia/arthritis, second/third-degree AV heart block, chronic pain syndromes, and chronic skin conditions that reduce the ability to detect cutaneous manifestations of Lyme disease.
- Any autoimmune condition with a manifestation (eg, arthritic and neurologic) that may interfere with the assessment of Lyme disease.
- Chronic systemic doxycycline or minocycline or other tetracycline class drug use for acne or any other chronic suppressive antibiotics used to treat other conditions.

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT05477524
Contact: Pfizer CT.gov Call Center | 1-800-718-1021 | ClinicalTrials.gov_Inquiries@pfizer.com |

Study Director: | Pfizer CT.gov Call Center | Pfizer |
Responsible Party: | Pfizer |
ClinicalTrials.gov Identifier: | NCT05477524 |
Other Study ID Numbers: |
C4601003 2021-005427-20 ( EudraCT Number ) 2021-005427-20 ( Registry Identifier: CTIS (EU) ) |
First Posted: | July 28, 2022 Key Record Dates |
Last Update Posted: | March 21, 2023 |
Last Verified: | March 2023 |
Individual Participant Data (IPD) Sharing Statement: | |
Plan to Share IPD: | Yes |
Plan Description: | Pfizer will provide access to individual de-identified participant data and related study documents (e.g. protocol, Statistical Analysis Plan (SAP), Clinical Study Report (CSR)) upon request from qualified researchers, and subject to certain criteria, conditions, and exceptions. Further details on Pfizer's data sharing criteria and process for requesting access can be found at: https://www.pfizer.com/science/clinical_trials/trial_data_and_results/data_requests. |
URL: | https://www.pfizer.com/science/clinical_trials/trial_data_and_results/data_requests |
Studies a U.S. FDA-regulated Drug Product: | Yes |
Studies a U.S. FDA-regulated Device Product: | No |
VLA15 Lyme Borreliosis Vaccine |
Lyme Disease Gram-Negative Bacterial Infections Bacterial Infections Bacterial Infections and Mycoses Infections |
Borrelia Infections Spirochaetales Infections Tick-Borne Diseases Vector Borne Diseases |