An Efficacy, Safety, and Immunogenicity Study of CHIKV VLP Vaccine for the Prevention of Chikungunya Disease in Adolescents and Adults

A Phase 3b Randomized, Double-blind, Placebo-controlled Study to Evaluate the Efficacy, Safety, and Immunogenicity of an Adjuvanted Chikungunya Virus Virus-like Particle (CHIKV VLP) Vaccine for the Prevention of Chikungunya Disease in Adolescents (12 to <18 Years) and Adults (≥18 Years)

Study EBSI-CV-317-007 is a field study to evaluate the efficacy, immunogenicity, and safety of CHIKV VLP vaccine. The study was designed using infectious disease models and advanced analytics to guide region and clinical site prioritization, define the timing of study activities, and optimize the study parameters to local epidemiological conditions for CHIKV disease to overcome the challenges of assessing efficacy for CHIKV VLP vaccine.

Study Overview

• Status: Not yet recruiting
• Conditions: Chikungunya Virus
• Intervention / Treatment: Biological: CHIKV VLP vaccine; Biological: Placebo

• Study Type: Interventional
• Enrollment (Estimated): 6144
• Phase: Phase 3

Contacts and Locations

• Study Contact: Name: Anjali Chudasama, MPH M.Sc.; Phone Number: 844-422-8274; Email: info@bavarian-nordic.com
• Study Contact Backup: Name: Tiffany Brockington; Email: info@bavarian-nordic.com

Study Locations

• Philippines
  • Cebu
    • Cebu City, Cebu, Philippines, 6000
      • WRAIR-AFRIMS Philippines, Cebu (WRAIR-APC)
      • Contact: Bavarian Nordic Investigative Site
• Thailand
  • Changwat Kamphaeng Phet
    • Kamphaeng Phet, Changwat Kamphaeng Phet, Thailand, 62000
      • Kamphaeng Phet Provincial Hospital
      • Contact: Bavarian Nordic Investigative Site
  • Changwat Songkhla
    • Hat Yai, Changwat Songkhla, Thailand, 90110
      • Songklanagarind hospital, Prince of Songkla University (PSU)
      • Contact: Bavarian Nordic Investigative Site

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

1. Able and willing to provide informed consent (and assent, as applicable) voluntarily signed by participant (and guardian, as applicable). Must verbalize understanding of the reason for and the procedures needed for the study and be willing to stay in the study for its entire duration.
2. Male or nonpregnant female 12 years of age and older.
3. In stable health per the investigator, and no hospital admission or major surgical procedure in the last 30 days before investigational product administration.
4. Negative for CHIKV antibodies as determined by CHIK IgM/IgG rapid diagnostic test (RDT), except for the Safety Subset which may be enrolled regardless of serostatus.

5. Women who are either:

   1. Not of CBP: premenarchal, surgically sterile (at least 6 weeks post bilateral tubal ligation, bilateral salpingectomy, bilateral oophorectomy, or hysterectomy); or postmenopausal (defined as a history of ≥12 consecutive months without menses prior to randomization in the absence of other pathologic or physiologic causes, following cessation of exogenous sex-hormonal treatment). or

   2. Meeting all the below criteria:

      • Negative urine pregnancy test at screening visit
      • Negative urine pregnancy test immediately prior to dosing
      • Using an acceptable form of contraception per local standards and agree to use this for at least 8 weeks after investigational product administration

Note: Contraception requirements do not apply for participants in exclusively same-sex relationships and these participants should have no plans to become pregnant by any other means for at least 8 weeks after investigational product administration.

Exclusion Criteria:

1. Currently pregnant or breastfeeding.
2. Participation or planned participation in an investigational clinical study within 30 days of Day 1 (investigational product administration) and for the duration of the study. Note: Participation in an observational trial/study or follow-up phase of a trial/study may be eligible; however, participation in any other study should be discussed with the MM prior to enrollment.
3. History of severe allergic reaction or anaphylaxis to any component of the investigational product.
4. Prior receipt of any CHIKV vaccine (or therapeutic) or participation in a prior interventional CHIKV trial/study.
5. Prior documented, laboratory confirmed CHIKV disease.
6. History of any known congenital or acquired immunodeficiency or immunosuppressive condition that could impact response to investigational product administration (eg, leukemia, lymphoma, malignancy, functional or anatomic asplenia, alcoholic cirrhosis). Notes: i) history of basal cell and squamous cell carcinoma of the skin or carcinoma in situ of the cervix considered cured is not exclusionary; ii) history of malignancy considered cured from over 5 years from the date of screening with minimal risk of reoccurrence or relapse is not exclusionary; iii) documented controlled HIV infection (most recent tests show undetectable viral load and a CD4 cell count over 350 at the time of investigational product administration) is not exclusionary.
7. Prior receipt or anticipated use of systemic immunomodulatory or immunosuppressive medications including hyperimmune products, monoclonal antibody therapies, systemic corticosteroids, and/or therapy with alkylating agents, antimetabolites, or radiation from 6 months prior to screening through Day 22 visit (21 days [-3/+5] after investigational product administration). Note: i) for systemic corticosteroid uses at a dose or equivalent dose of 20 mg of prednisone daily for 14 days or more within 90 days of screening through Day 22 visit is exclusionary, and ii) use of inhaled, intranasal, topical, or ocular steroids is not exclusionary.
8. Receipt or anticipated receipt of any vaccine from 30 days prior to Day 1 through Day 22 visit.
9. Unstable medical condition in the last 30 days prior to Day 1.
10. Acute illness with or without fever (oral temperatures ≥38.0 ºC [100.4 °F]) within 14 days prior to investigational product administration.
11. Medical or social condition (eg, substance abuse) that could have an impact on the participant's ability to be compliant with study procedures/visits, as determined by the investigator.
12. Plans to travel outside the study area or move away for more than 3 consecutive months and will not be available for follow up at the site.
13. Identified as an investigator or employee of an investigator or study center with direct involvement in the proposed study, or identified as an immediate family member (ie, parent, spouse) of the investigator or employee with direct involvement in the proposed study, or identified as an employee of Bavarian Nordic, their families, contractors, agents, business partners, or anyone with a financial interest in the outcome of the study.
14. Any other medical condition that, in the opinion of the investigator, could adversely impact the participant's participation or the conduct of the study.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Quadruple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Arm 1: Cohort 1 Active Group; CHIKV VLP/adjuvant	Biological: CHIKV VLP vaccine; CHIKV VLP vaccine is comprised of 40 µg CHIKV VLP adsorbed on aluminum hydroxide (corresponding to approximately 300 µg of aluminum and stabilized with formulation buffer). CHIKV VLP vaccine is supplied as a single dose of 0.8 mL in a single use pre-filled syringe administered via IM injection in the deltoid muscle.
Placebo Comparator: Arm 2: Cohort 1 Placebo Group; Placebo	Biological: Placebo; Placebo is comprised of formulation buffer supplied as a single dose of 0.8 mL in a single use pre-filled syringe administered via IM injection in the deltoid muscle.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incidence of laboratory-confirmed acute CHIKV disease	Laboratory-confirmed acute CHIKV disease is defined by the presence of fever, one or more of arthralgia, myalgia or rash, and reverse transcription-quantitative polymerase chain reaction (RT-qPCR) confirmation of CHIKV ribonucleic acid.	From 14 days postvaccination through end of study follow-up, up to 1095 days postvaccination

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incidence of laboratory-confirmed chronic CHIKV disease	Laboratory-confirmed chronic CHIKV disease is defined as the persistence of at least one of the articular manifestations (continuous or recurrent pain, rigidity, edema) for >12 weeks after the onset of laboratory confirmed acute CHIKV disease.	98 days postvaccination through end of study follow-up, up to 1095 days postvaccination
Incidence of laboratory-confirmed severe CHIKV disease.	Laboratory-confirmed severe CHIKV disease is defined as a laboratory confirmed acute CHIKV disease presenting with dysfunction of at least one organ or system that threatens life and requires hospitalization.	14 days postvaccination through end of study follow-up, up to 1095 days postvaccination
Number of participants with Solicited or Local Adverse Events	In the Safety Subset, the number and percentage of participants with local and systemic reactogenicity events through 7 days postvaccination.	Within 7 days postvaccination
Number of participants with Unsolicited Adverse Events	In the Safety Subset, the number and percentage of participants with unsolicited adverse events through 28 days postvaccination.	Within 28 days postvaccination
Number of Participants with Serious Adverse Events	For all study participants who receive investigational product, number and percentage of participants with Serious Adverse Events (SAEs). Note: All participants will be followed for a minimum duration of 6 months following investigational product administration.	Through end of study follow-up, up to 1095 days postvaccination
Number of Participants with Adverse Events of Special Interest	Adverse events of special interest are defined as the occurrence of new onset or worsening arthralgia that is medically attended and are not associated with a febrile disease case. For all study participants who receive investigational product, number and percentage of participants with AESI for the duration of the study. Note: All participants will be followed for a minimum duration of 6 months following investigational product administration.	Through end of study follow-up, up to 1095 days postvaccination
Number of Participants with Medically Attended Adverse Events	Medically attended adverse events (MAAEs) are defined as adverse events requiring a visit to the hospital, emergency room, urgent care clinic, or other visits to or from medical personnel that are not part of routine scheduled study visits. For study participants in the Safety Subset, the number and percentage of participants with MAAEs for the duration of the study. Note: All participants will be followed for a minimum duration of 6 months following investigational product administration.	Through end of study follow-up, up to 1095 days postvaccination
Anti-CHIKV Serum Neutralizing antibody titers	Geometric Mean Titers (GMTs) of anti-CHIKV serum neutralizing antibodies based on a validated luciferase based anti-CHIKV neutralization assay.	3 weeks postvaccination
Anti-CHIKV Serum Neutralizing Antibody seroresponse rate	Seroresponse is defined as the presence of anti-CHIKV serum neutralizing antibody (SNA) titer meeting or exceeding 100. Seroresponse rate is defined as the percentage of participants with an Anti-CHIKV SNA titer meeting or exceeding a titer of 100 based on a validated luciferase based anti-CHIKV neutralization assay.	3 weeks postvaccination

Collaborators and Investigators

• Sponsor: Bavarian Nordic
• Collaborators: United States Department of Defense; Walter Reed Army Institute of Research (WRAIR); Congressionally Directed Medical Research Programs; Pharmaceutical Product Development, (PPD) LLC; Armed Forces Research Institute of Medical Services; Q-square Business Intelligence, Inc.
• Investigators: Study Director: Patrick Ajiboye, MD, Bavarian Nordic A/S

Publications and helpful links

General Publications

• Bennett SR, McCarty JM, Ramanathan R, Mendy J, Richardson JS, Smith J, Alexander J, Ledgerwood JE, de Lame PA, Royalty Tredo S, Warfield KL, Bedell L. Safety and immunogenicity of PXVX0317, an aluminium hydroxide-adjuvanted chikungunya virus-like particle vaccine: a randomised, double-blind, parallel-group, phase 2 trial. Lancet Infect Dis. 2022 Sep;22(9):1343-1355. doi: 10.1016/S1473-3099(22)00226-2. Epub 2022 Jun 13.
• McCarty JM, Bedell L, Mendy J, Coates EE, Chen GL, Ledgerwood JE, Tredo SR, Warfield KL, Richardson JS. Chikungunya virus virus-like particle vaccine is well tolerated and immunogenic in chikungunya seropositive individuals. Vaccine. 2023 Oct 6;41(42):6146-6149. doi: 10.1016/j.vaccine.2023.08.086. Epub 2023 Sep 9.
• Richardson JS, Anderson DM, Mendy J, Tindale LC, Muhammad S, Loreth T, Tredo SR, Warfield KL, Ramanathan R, Caso JT, Jenkins VA, Ajiboye P, Bedell L; EBSI-CV-317-004 Study Group. Chikungunya virus virus-like particle vaccine safety and immunogenicity in adolescents and adults in the USA: a phase 3, randomised, double-blind, placebo-controlled trial. Lancet. 2025 Apr 19;405(10487):1343-1352. doi: 10.1016/S0140-6736(25)00345-9. Epub 2025 Mar 27.
• Tindale LC, Richardson JS, Anderson DM, Mendy J, Muhammad S, Loreth T, Tredo SR, Ramanathan R, Jenkins VA, Bedell L, Ajiboye P; EBSI-CV-317-005 Study Group. Chikungunya virus virus-like particle vaccine safety and immunogenicity in adults older than 65 years: a phase 3, randomised, double-blind, placebo-controlled trial. Lancet. 2025 Apr 19;405(10487):1353-1361. doi: 10.1016/S0140-6736(25)00372-1. Epub 2025 Mar 27.

Study record dates

Study Major Dates

• Study Start (Estimated): May 1, 2026
• Primary Completion (Estimated): May 1, 2030
• Study Completion (Estimated): May 1, 2030

Study Registration Dates

• First Submitted: March 9, 2026
• First Submitted That Met QC Criteria: March 9, 2026
• First Posted (Actual): March 12, 2026

Study Record Updates

• Last Update Posted (Actual): March 16, 2026
• Last Update Submitted That Met QC Criteria: March 12, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Keywords: safety; vaccine; efficacy; adolescents; immunogenicity; adults; Chikungunya; PXVX0317; CHIKV VLP; VIMKUNYA
• Additional Relevant MeSH Terms: Vector Borne Diseases; Mosquito-Borne Diseases; Infections; RNA Virus Infections; Virus Diseases; Arbovirus Infections; Alphavirus Infections; Togaviridae Infections; Chikungunya Fever
• Other Study ID Numbers: EBSI-CV-317-007

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No