Long-term Follow-up Study to Evaluate Safety and Immunogenicity of PXVX0317 Single or Booster Vaccination

NCT ID: NCT06007183

Last Updated: 2025-04-03

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

ACTIVE_NOT_RECRUITING

Clinical Phase

PHASE3

Total Enrollment

800 participants

Study Classification

INTERVENTIONAL

Study Start Date

2023-08-30

Study Completion Date

2028-08-31

Brief Summary

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The purpose of this phase 3 multicenter, randomized, double-blind, placebo-controlled rollover study is to evaluate the safety and long-term immunogenicity of CHIKV VLP vaccine in adult and adolescent participants and to evaluate CHIKV VLP booster vaccine induced serum neutralizing antibody (SNA) response at 3, 4, or 5 years post-initial CHIKV VLP vaccination.

Detailed Description

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Primary Objectives:

* To evaluate the long-term immunogenicity of CHIKV VLP vaccine in healthy adult and adolescent participants as measured by proportion of participants maintaining an anti-CHIKV serum neutralizing antibody (SNA) titer ≥100 (seroresponse rate, also considered the presumptive seroprotection rate) at yearly intervals up to 5 years postvaccination in feeder studies EBSI-CV-317-004 (NCT05072080) and EBSI-CV-317-005 (NCT05349617).
* To assess the vaccine-induced SNA titers by a booster dose of CHIKV VLP vaccine at 3, 4, or 5 years post-initial vaccination in feeder studies EBSI-CV- 317-004 and EBSI-CV-317-005.
* To evaluate the safety and tolerability of CHIKV VLP vaccine in all participants.
* To evaluate the safety and tolerability of a booster vaccination and compare with safety and tolerability reported post-initial vaccination of CHIKV VLP vaccine under feeder studies EBSI-CV-317-004 and EBSI-CV-317-005 in healthy adults and adolescents.

Secondary Objectives:

* To evaluate the long-term immunogenicity of CHIKV VLP vaccine in healthy adult and adolescent participants as measured by anti-CHIKV SNA geometric mean titers (GMTs) at yearly intervals up to 5 years post-initial vaccination in feeder studies EBSI-CV-317-004 and EBSI-CV-317-005.
* To evaluate the immune response to a booster vaccination and compare this response to that reported post-initial vaccination of CHIKV VLP vaccine under feeder studies EBSI-CV-317-004 and EBSI-CV-317-005 in healthy adults and adolescents.

Conditions

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Chikungunya Virus Infection

Study Design

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Allocation Method

RANDOMIZED

Intervention Model

PARALLEL

All eligible participants in the youngest (12 to \<18 years) and oldest 2 (≥65 years) age groups will be assigned to a booster at Year 3 (Group 1). All other participants will be randomized 1:1:1 to a booster at Year 3 (Group 1), 4 (Group 2), or 5 (Group 3). Prior to booster dose administration participants will be randomized 1:1 to CHIKV VLP vaccine booster or placebo booster.
Primary Study Purpose

PREVENTION

Blinding Strategy

TRIPLE

Participants Caregivers Investigators
Participants, care providers, and investigator will not be blinded for the timing of when the participant will receive the vaccine booster or placebo booster. They will be blinded to all booster treatment assignments (vaccine booster or placebo booster).

Study Groups

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Group 1a

CHIKV VLP vaccine booster, 3 years post initial vaccination

Group Type ACTIVE_COMPARATOR

CHIKV VLP vaccine booster

Intervention Type BIOLOGICAL

CHIKV VLP vaccine is comprised of chikungunya virus virus-like particles (CHIKV VLP) 40mg, aluminum hydroxide 2% adjuvant, and formulation buffer supplied as a single dose of 0.8 mL in a pre-filled syringe, to be administered via intramuscular (IM) injection in the deltoid muscle.

Group 1b

Placebo booster, 3 years post initial vaccination

Group Type PLACEBO_COMPARATOR

Placebo booster

Intervention Type BIOLOGICAL

Placebo is comprised of formulation buffer supplied as a single dose of 0.8 mL in a pre-filled syringe administered via IM injection in the deltoid muscle.

Group 2a

CHIKV VLP vaccine booster, 4 years post initial vaccination

Group Type ACTIVE_COMPARATOR

CHIKV VLP vaccine booster

Intervention Type BIOLOGICAL

CHIKV VLP vaccine is comprised of chikungunya virus virus-like particles (CHIKV VLP) 40mg, aluminum hydroxide 2% adjuvant, and formulation buffer supplied as a single dose of 0.8 mL in a pre-filled syringe, to be administered via intramuscular (IM) injection in the deltoid muscle.

Group 2b

Placebo booster, 4 years post initial vaccination

Group Type PLACEBO_COMPARATOR

Placebo booster

Intervention Type BIOLOGICAL

Placebo is comprised of formulation buffer supplied as a single dose of 0.8 mL in a pre-filled syringe administered via IM injection in the deltoid muscle.

Group 3a

CHIKV VLP vaccine booster, 5 years post initial vaccination

Group Type ACTIVE_COMPARATOR

CHIKV VLP vaccine booster

Intervention Type BIOLOGICAL

CHIKV VLP vaccine is comprised of chikungunya virus virus-like particles (CHIKV VLP) 40mg, aluminum hydroxide 2% adjuvant, and formulation buffer supplied as a single dose of 0.8 mL in a pre-filled syringe, to be administered via intramuscular (IM) injection in the deltoid muscle.

Group 3b

Placebo booster, 5 years post initial vaccination

Group Type PLACEBO_COMPARATOR

Placebo booster

Intervention Type BIOLOGICAL

Placebo is comprised of formulation buffer supplied as a single dose of 0.8 mL in a pre-filled syringe administered via IM injection in the deltoid muscle.

Group 4

Unrandomized or unboosted participants, for any reason

Group Type NO_INTERVENTION

No interventions assigned to this group

Interventions

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CHIKV VLP vaccine booster

CHIKV VLP vaccine is comprised of chikungunya virus virus-like particles (CHIKV VLP) 40mg, aluminum hydroxide 2% adjuvant, and formulation buffer supplied as a single dose of 0.8 mL in a pre-filled syringe, to be administered via intramuscular (IM) injection in the deltoid muscle.

Intervention Type BIOLOGICAL

Placebo booster

Placebo is comprised of formulation buffer supplied as a single dose of 0.8 mL in a pre-filled syringe administered via IM injection in the deltoid muscle.

Intervention Type BIOLOGICAL

Other Intervention Names

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PXVX0317

Eligibility Criteria

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Inclusion Criteria

* Only within the EBSI-CV-317-004 feeder study informed consent form (ICF) (and/or assent form, as applicable), the participant voluntarily signed and agreed to be contacted or did not indicate they were not to be contacted for potential screening and enrollment in a future study (ie, EBSI-CV-317-008).
* Able and willing to provide informed consent (and assent, as applicable) voluntarily signed by participant (and guardian, as applicable) for participation in this rollover study EBSI-CV-317-008, including possible receipt of a booster dose of CHIKV VLP vaccine.
* Males or females, 12 years of age or older at the time of enrollment in the feeder study.
* Received a single dose of CHIKV VLP vaccine in one of the feeder studies, EBSI-CV-317-004 or EBSI-CV-317-005.
* Demonstrated compliance to the feeder study conduct (ie, rollover participant was without protocol deviations that excluded them from immunogenicity analysis in feeder study EBSI-CV-317-004 or EBSI-CV-317-005) without discontinuation or early withdrawal.
* Generally healthy, in the opinion of the investigator, based on medical history and physical examination.


\- Women who are either: i. Not of childbearing potential (CBP): premenarche, surgically sterile (at least six weeks postbilateral tubal ligation or bilateral total 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). For women who are postmenopausal, documented follicle stimulating hormone (FSH) level of ≥40 mIU/mL must be obtained. If the FSH is \<40 mIU/mL, the participant must agree to use an acceptable form of contraception. or: ii. Meet all the below criteria:

* Negative serum pregnancy test at Prerandomization and Prebooster Visits
* Negative urine pregnancy test immediately prior to booster dose administration
* Use one of these acceptable methods of contraception (if women of CBP) for at least six months after booster:
* Hormonal contraceptives (eg, implants, pills, patches) initiated ≥30 days prior to booster dose administration
* Intrauterine device (IUD) inserted ≥30 days prior to booster dose administration
* Double barrier type of birth control (male condom with female diaphragm, male condom with cervical cap)
* Abstinence is acceptable only for adolescents (12-\<18 years of age) who are not sexually active.

Women participants of CBP must use an acceptable method of contraception from ≥30 days prior to Randomization A or assignment to Group 1; those who are randomized to Groups 2 or 3 at year 3 can discontinue contraception until 30 days prior to booster dose administration, if desired. Women participants of CBP must use an acceptable method of contraception from ≥30 days prior to Randomization B through six-months postbooster vaccination dose (if applicable).

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 during the same time period as women of CBP are required to use contraception. Contraception requirements do not apply to Group 4 participants (unrandomized or unboosted).

Exclusion Criteria

* Received placebo treatment in the feeder study.
* Measurable anti-CHIKV SNA at Day 1 in the feeder study.
* History of severe allergic reaction or anaphylaxis to any component of the investigational product (IP).
* Receipt of either an investigational or licensed CHIKV vaccine (excluding prior receipt of CHIKV VLP vaccine).
* Evidence of substance abuse that, in the opinion of the investigator, could adversely impact the individual's participation or the conduct of the study.
* Any other medical condition or general reason that, in the opinion of the investigator, could adversely impact the individual's participation or the conduct of the study.
* Bavarian Nordic staff members and their families, contractors, agents, business partners, and anyone with a financial interest in the outcome of the study.


* Participation or planned participation in an investigational clinical trial, excluding feeder studies EBSI-CV-317-004 or EBSI-CV-317-005 (eg, vaccine, drug, medical device, or medical procedure) for the following time periods:

Group 1: 30 days prior to Randomization A or assignment to Group 1 at Visit 6 through Visit 7 Group 2: 30 days prior to Randomization A at Visit 6 until the Randomization A visit and 30 days prior to booster dose at Visit 8 through Visit 9 Group 3: 30 days prior to Randomization A at Visit 6 until the Randomization A visit and 30 days prior to booster dose at Visit 10 through EOS Visit Group 4: 30 days prior to Randomization A at Visit 6 until the Randomization A visit Note: Participation in an observational trial or follow-up phase of a trial may be allowed; however, these instances should be discussed with this study's medical monitor (MM).

* Currently breastfeeding.
* Positive laboratory evidence of current infection with human immunodeficiency virus (HIV), hepatitis C virus (HCV) or hepatitis B virus (HBV).
* Prior receipt or anticipated use of systemic immunomodulatory or immunosuppressive medications from six months prior to Prebooster Visit through 21 days after booster dose. Note: For systemic corticosteroids, use at a dose or equivalent dose of 20 mg of prednisone daily for 14 days or more within three months of Prebooster Visit through 21 days postbooster dose is exclusionary. The use of inhaled, intranasal, topical, ocular, or intraocular steroids is allowed.
* Receipt or anticipated receipt of blood or blood-derived products from 90 days prior to Prebooster Visit through 21 days postbooster dose.
* Acute disease within the last 14 days prior to booster dose (participants with an acute mild febrile illness can be considered for a deferral of vaccination two weeks after the illness has resolved and treatment has been completed).
* Receipt or anticipated receipt of any vaccine from 30 days prior to booster dose through 21 days postbooster.

Note: Participants that are ineligible or decline booster will be included in Group 4 (unrandomized or unboosted) for follow-up unless consent/assent for follow-up is withdrawn.
Minimum Eligible Age

12 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

Yes

Sponsors

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Bavarian Nordic

INDUSTRY

Sponsor Role lead

Responsible Party

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Responsibility Role SPONSOR

Principal Investigators

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Patrick Ajiboye, MD

Role: STUDY_DIRECTOR

Bavarian Nordic

Locations

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Alliance for Multispecialty Research, LLC

Mobile, Alabama, United States

Site Status

Alliance for Multispecialty Research, LLC

Tempe, Arizona, United States

Site Status

Optimal Research, LLC

Melbourne, Florida, United States

Site Status

Suncoast Research Associates, LLC

Miami, Florida, United States

Site Status

Synexus Clinical Research US, Inc.

Chicago, Illinois, United States

Site Status

Optimal Research, LLC

Peoria, Illinois, United States

Site Status

Alliance for Multispecialty Research, LLC

Newton, Kansas, United States

Site Status

Alliance for Multispecialty Research, LLC

Wichita, Kansas, United States

Site Status

Alliance for Multispecialty Research, LLC

Lexington, Kentucky, United States

Site Status

Alliance for Multispecialty Research, LLC

Kansas City, Missouri, United States

Site Status

Wr-Crcn, Llc

Las Vegas, Nevada, United States

Site Status

Alliance for Multispecialty Research, LLC

Las Vegas, Nevada, United States

Site Status

Rochester Clinical Research, LLC

Rochester, New York, United States

Site Status

M3 Wake Research Inc.

Raleigh, North Carolina, United States

Site Status

Velocity Clinical Research, Cleveland

Cleveland, Ohio, United States

Site Status

Lynn Institute of Norman

Norman, Oklahoma, United States

Site Status

Velocity Clinical Research, Medford

Medford, Oregon, United States

Site Status

Velocity Clinical Research, Providence

East Greenwich, Rhode Island, United States

Site Status

Velocity Clinical Research, Austin

Cedar Park, Texas, United States

Site Status

DM Clinical Research

Houston, Texas, United States

Site Status

BFHC Research, LLC

San Antonio, Texas, United States

Site Status

DM Clinical Research

Tomball, Texas, United States

Site Status

Velocity Clinical Research, Salt Lake City

West Jordan, Utah, United States

Site Status

Alliance for Multispecialty Research, LLC

Norfolk, Virginia, United States

Site Status

Countries

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United States

Other Identifiers

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EBSI-CV-317-008

Identifier Type: -

Identifier Source: org_study_id

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