Clinical Trial: Safety of and Immune Response to a Tick-Borne Encephalitis Vaccine (LGT(TP21)/DEN4) in Healthy Adults

Study Status: Completed
Recruit Status: Completed
Study Type: Interventional

Official Title: Phase 1 Study of the Safety and Immunogenicity of Tick-Borne Langat/Dengue 4 Chimera (LGT(TP21)/DEN4), a Live Attenuated Vaccine for Tick-Borne Encephalitis

Brief Summary: Tick-borne encephalitis (TBE) is a viral illness common in the Northern Hemisphere, especially Europe and Asia. TBE infection may lead to central nervous system problems and death. The purpose of this study is to test the safety of and immune response to a TBE vaccine in healthy adults. The vaccine is related to a live attenuated virus developed against dengue virus infection.

Detailed Summary:

TBE is a common illness in Europe and Asia, where it is usually associated with mild illness but sometimes leads to long-term symptoms and even death. This study will evaluate the safety and immunogenicity of a live attenuated chimeric virus, LGT(TP21)/DEN4, which is derived from the Langat flavivirus and DEN4 dengue virus serotypes.

Each volunteer will be involved in the study for 180 days. Participants in Cohort 1 will be randomly assigned to receive LGT(TP21)/DEN4 or placebo at study entry. Cohort 2 will begin only after safety review of all participants in Cohort 1. Participants in Cohort 2 will receive a higher dose of LGT(TP21)/DEN4 or placebo.

After vaccination, participants will be asked to monitor their temperatures every day for 16 days and on Day 19. Study visits will occur every other day after vaccination until Day 16, followed by 5 additional visits at selected days through Day 180. Blood collection and a targeted physical exam will occur at each study visit. Some participants will be asked to undergo a skin biopsy or additional blood collection at selected visits.


Sponsor: National Institute of Allergy and Infectious Diseases (NIAID)

Current Primary Outcome:

  • Frequency of vaccine-related adverse effects, graded by intensity and severity through active and passive surveillance [ Time Frame: Throughout study ]
  • Immunogenicity of vaccine against anti-Langat neutralizing antibody [ Time Frame: At Days 0, 28, 42, and 180 ]


Original Primary Outcome:

  • Frequency of vaccine-related adverse effects, graded by intensity and severity through active and passive surveillance
  • immunogenicity of vaccine against anti-Langat neutralizing antibody on Days 0, 28, 42, and 180


Current Secondary Outcome:

  • Recovery of virus from the blood of a vaccinee or seroconversion [ Time Frame: Throughout study ]
  • Immunogenicity of the LGT(TP21)/DEN4 vaccine against other TBE viruses [ Time Frame: Throughout study ]
  • Durability of antibody responses to Langat and other TBE viruses [ Time Frame: At Day 180 ]


Original Secondary Outcome:

  • Recovery of virus from the blood of a vaccinee or seroconversion
  • Immunogenicity of the LGT(TP21)/DEN4 vaccine against other TBE viruses
  • durability of antibody responses to Langat and other TBE viruses at 6 months (180 days)


Information By: National Institute of Allergy and Infectious Diseases (NIAID)

Dates:
Date Received: July 8, 2005
Date Started: July 2005
Date Completion:
Last Updated: January 18, 2008
Last Verified: January 2008