Persistence Study of GSK Biologicals' Tdap Vaccine 1, 3, 5 and 9 Years Following Administration as an Initial Single Dose in Healthy Young Adults and to Evaluate the Immunogenicity and Safety of Boostrix as a Second Dose of Tdap, When Administered at Year 9

Tetanus Clinical Trial

Official title: Persistence Study of GSK Biologicals' Tdap Vaccine (776423), 1, 3, 5 and 9 Years Following Administration as a Single Dose in NCT00346073 Study and to Evaluate the Immunogenicity and Safety of Boostrix as a Second Dose of Tdap, When Administered at Year 9

Status Completed

Clinical Trial Summary

The purpose of this study is to evaluate the persistence of antibodies against all the vaccine antigens 1, 3, 5 and 9 years after an initial vaccination with Tdap, and also to assess immunogenicity and safety of another dose of Boostrix, administered in this study.

This protocol posting deals with objectives and outcome measures of the extension phase. The objectives and outcome measures of the primary phase are presented in a separate protocol posting (NCT number = NCT00346073).

Clinical Trial Description

Subjects were previously vaccinated with either Boostrix or a control Tdap vaccine (Sanofi Pasteurs' Adacel) in study NCT00346073. Only subjects who were part of the primary study will be invited to participate in this study. All subjects will receive a single dose of Boostrix at Visit 6 (Day 0) and subjects will be observed till Visit 7 (Day 30) for safety in terms of solicited adverse events (during 4 days post vaccination), unsolicited adverse events (during 31 days post vaccination) and serious adverse event (during the trial period). A blood sample will be collected from all subjects before vaccination (Visit 6) and one month after vaccination (Visit 7) for antibodies estimation.

This summary has been updated following Protocol amendment 1 dated 09 November 2010, amendment 2 dated 18 February 2014, and amendment 3 dated 10 December 2014. The protocol was amended first due to the following reasons:

1. The maximum window period allowed for the return of subjects for the Year 5 and Year 10 follow-up visits (Visit 5 and Visit 6) was extended from ± 5 weeks to ± 8 weeks.

2. The contact details for reporting of SAEs were clarified.

3. Text pertaining to the reporting of spontaneous abortion was removed from the protocol.

4. The number of attempts to contact subjects who did not return for scheduled persistence visits was clarified.

The main purpose of protocol amendment 2 is to evaluate the immunogenicity and safety of Boostrix as a second dose of Tdap vaccine when administered 8 years after an initial dose of Tdap. The Year 10 time point for evaluation of persistence has been cancelled because it is no longer feasible to conduct after a second dose of Tdap vaccine has been administered at Year 8.

The purpose of amendment 3 is to add co-primary objective to demonstrate that the immune response elicited by a second dose of Tdap vaccine, Boostrix (Boostrix group and Adacel group) is non-inferior to the immune response elicited by a first dose of Tdap vaccine (Control group), with respect to booster response against diphtheria, tetanus and pertussis (PT, FHA and PRN) antigens, one month following vaccination according to CBER's input. Accordingly, the study start has been pushed to Year 9 and this is reflected throughout the document. ;

Related Conditions & MeSH terms

• Acellular Pertussis
• Diphtheria
• Tetanus

• NCT number: NCT00489970
• Study type: Interventional
• Source: GlaxoSmithKline
• Status: Completed
• Phase: Phase 3
• Start date: June 1, 2007
• Completion date: March 1, 2016