An Extension Study of EV-BR1701 Part A1
Long-Term Immunogenicity Study of an Adjuvanted Inactivated Enterovirus 71 (EV71) Vaccine in Healthy Infants and Children: An Extension Study of EV-BR1701 Part A1
Aperçu de l'étude
Statut
Les conditions
Description détaillée
I. Study Design:
EV-BR1701 was a randomized, multi-nation, multi-centered, double-blinded, phase III study to evaluate the efficacy and safety of an EV71 vaccine, EnVAX-A71, in healthy infants and children in Taiwan (Part A) and Vietnam (Part B). In both Parts, a sub-study for immunogenicity assessment for up to one year was performed. This extension study of EV-BR1701 aims to evaluate the long-term immunogenicity persistence more than 5 years after EnVAX-A71 vaccination in subjects originally participating in the immunogenicity sub-study in Taiwan.
The evaluable subjects of EV-BR1701 Part A1(immunogenicity sub-study), who were aged 2 months to < 6 years when entering the main study and completed two injections of either EnVAX-A71 or placebo with evaluable data for the primary immunogenicity endpoint, will be recalled to enter this extension study for phlebotomy and immunogenicity analysis. These subjects will not receive further vaccination according to this extension study protocol.
The principal investigators (PIs) and study coordinators (SCs) of the original medical center will contact the subject's guardians/legal representative by phone to return to the medical center for phlebotomy. Informed consent will be provided to the guardian/legal representative of the subjects, and the eligibility of subjects will be verified on the day of the recall visit.
After the subject is evaluated by the PI and meets the phlebotomy requirements, the subject's guardian/legal representative will be asked to sign the informed consent form, and the subject will be given the same identifier as what he/she was originally assigned in the main study for continuity of his/her immunogenicity data.
About 3-4 mL of blood will be collected from each subject, and the serum will be collected and sent to the designated central laboratory for testing. The validated neutralizing antibody (NTAb) analysis method will be used to determine the EV71-specific neutralizing antibody titer. The NTAb titer results will be directly sent to the CRO Data Management Team, and statistical analysis for immunogenicity will be performed and reported.
Type d'étude
Inscription (Réel)
Contacts et emplacements
Lieux d'étude
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Hsinchu, Taïwan
- National Taiwan University Hospital HsinChu Branch
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Taichung, Taïwan
- China Medical University Hospital
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Taipei, Taïwan
- National Taiwan University Hospital
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Taoyuan, Taïwan
- Linkou Chang Gung Memorial Hospital
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Critères de participation
Critère d'éligibilité
Âges éligibles pour étudier
- Enfant
Accepte les volontaires sains
Méthode d'échantillonnage
Population étudiée
La description
Inclusion Criteria:
- Healthy children who were enrolled in Part A1 (immunogenicity sub-study) of EV-BR1701, received two injections of either EnVAX-A71 or placebo, and had blood sample collected on Day 56 for primary immunogenicity endpoint analysis (the "evaluable" subjects).
- The subject's guardian/legal representative is able and willing to comply with study procedures and provide signed informed consent.
Exclusion Criteria:
- History of bleeding disorder, hemostatic difficulties or significant bruising caused by phlebotomy since the last visit in EV-BR1701 main study.
- Having been vaccinated with any EV71 vaccine products.
Plan d'étude
Comment l'étude est-elle conçue ?
Détails de conception
Que mesure l'étude ?
Principaux critères de jugement
Mesure des résultats |
Description de la mesure |
Délai |
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The long-term immunogenicity of EnVAX-A71 on the seroconversion rate (SCR)
Délai: From Sep-2025 to Dec-2025
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SCR (seroconversion rate) is defined as the percentage of subjects achieving either a pre-vaccination neutralizing antibody titer <1:8 and a post-vaccination neutralizing antibody titer ≥1:32, OR a pre-vaccination neutralizing antibody titer ≥1:8 and a minimum 4-fold increase in post-vaccination neutralizing antibody titer.
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From Sep-2025 to Dec-2025
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The long-term immunogenicity of EnVAX-A71 on SPR
Délai: From Sep-2025 to Dec-2025
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SPR (seroprotection rate, the proportion of the subjects with NTAb against EV71 titer ≥1:32)
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From Sep-2025 to Dec-2025
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The long-term immunogenicity of EnVAX-A71 on the geometric mean titer (GMT) and geometric mean titer ratio (GMTR) of EV71 neutralizing antibody (NTAb)
Délai: From Sep-2025 to Dec-2025
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GMTR (geometric mean titer ratio) is defined as the GMT at the recall visit divided by the GMT at pre-vaccination (Day 0 of main study).
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From Sep-2025 to Dec-2025
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Collaborateurs et enquêteurs
Parrainer
Les enquêteurs
- Directeur d'études: Wendy Wu, Enimmune Corporation
Dates d'enregistrement des études
Dates principales de l'étude
Début de l'étude (Réel)
Achèvement primaire (Réel)
Achèvement de l'étude (Réel)
Dates d'inscription aux études
Première soumission
Première soumission répondant aux critères de contrôle qualité
Première publication (Réel)
Mises à jour des dossiers d'étude
Dernière mise à jour publiée (Réel)
Dernière mise à jour soumise répondant aux critères de contrôle qualité
Dernière vérification
Plus d'information
Termes liés à cette étude
Termes MeSH pertinents supplémentaires
Autres numéros d'identification d'étude
- EV-BR1701 Part A1 Extension
Plan pour les données individuelles des participants (IPD)
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Informations sur les médicaments et les dispositifs, documents d'étude
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