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

Official title

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)

Overview

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.

Interventions

• 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.
• 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.

Primary outcome measures

• Incidence of laboratory-confirmed acute CHIKV disease [Time frame: From 14 days postvaccination through end of study follow-up, up to 1095 days postvaccination]

Secondary outcome measures (9)

• Incidence of laboratory-confirmed chronic CHIKV disease [Time frame: 98 days postvaccination through end of study follow-up, up to 1095 days postvaccination]
• Incidence of laboratory-confirmed severe CHIKV disease. [Time frame: 14 days postvaccination through end of study follow-up, up to 1095 days postvaccination]
• Number of participants with Solicited or Local Adverse Events [Time frame: Within 7 days postvaccination]
• Number of participants with Unsolicited Adverse Events [Time frame: Within 28 days postvaccination]
• Number of Participants with Serious Adverse Events [Time frame: Through end of study follow-up, up to 1095 days postvaccination]
• Number of Participants with Adverse Events of Special Interest [Time frame: Through end of study follow-up, up to 1095 days postvaccination]
• Number of Participants with Medically Attended Adverse Events [Time frame: Through end of study follow-up, up to 1095 days postvaccination]
• Anti-CHIKV Serum Neutralizing antibody titers [Time frame: 3 weeks postvaccination]
• Anti-CHIKV Serum Neutralizing Antibody seroresponse rate [Time frame: 3 weeks postvaccination]

Eligibility criteria

Inclusion criteria

• 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.
• Male or nonpregnant female 12 years of age and older.
• In stable health per the investigator, and no hospital admission or major surgical procedure in the last 30 days before investigational product administration.
• Women who are either:

• 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
• 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

• Currently pregnant or breastfeeding.
• 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.
• History of severe allergic reaction or anaphylaxis to any component of the investigational product.
• Prior receipt of any CHIKV vaccine (or therapeutic) or participation in a prior interventional CHIKV trial/study.
• Prior documented, laboratory confirmed CHIKV disease.
• 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.
• 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.
• Receipt or anticipated receipt of any vaccine from 30 days prior to Day 1 through Day 22 visit.
• Unstable medical condition in the last 30 days prior to Day 1.
• Acute illness with or without fever (oral temperatures ≥38.0 ºC \[100.4 °F\]) within 14 days prior to investigational product administration.
• 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.
• 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.
• 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.
• Any other medical condition that, in the opinion of the investigator, could adversely impact the participant's participation or the conduct of the study.

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: Yes

Study design

Allocation

Randomized

Model

Parallel assignment

Masking

Quadruple blind

Primary purpose

Prevention

Study locations

Thailand · 2 centers

• Kamphaeng Phet Provincial Hospital — Kamphaeng Phet
• Songklanagarind hospital, Prince of Songkla University (PSU) — Hat Yai

Philippines · 1 center

• WRAIR-AFRIMS Philippines, Cebu (WRAIR-APC) — Cebu City

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)0022 PMID 35709798
• 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. PMID 37690874
• 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: 1 PMID 40158526
• 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. PMID 40158524

Identifiers

NCT: NCT07467707 · EBSI-CV-317-007

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗