A Trial of the C-Tb Skin Test, When Given Intradermally to Healthy Volunteers Previously Vaccinated With BCG
Condition: Tuberculosis
MeSH terms: Tuberculosis
Study type: Interventional
Phase: Phase 2

Summary: 
      A new, more specific skin test to detect tuberculosis has been developed by Statens Serum
      Institut in Denmark. The new skin test is named C-Tb and like the current Tuberculin a
      positive test result will show as redness and/or swelling at the injection site, while a
      negative test will leave no reactions.

      The aim of this study is to test the C-Tb skin test in healthy adults previously BCG
      vaccinated to determine if healthy non tuberculosis infected individuals has a truly negative
      test result (this is called determining the specificity of the skin test). To be able to
      compare the new skin test with the current Tuberculin skin test volunteers will be injected
      with both the C-Tb and the TST skin test.
    

Detailed description: 
      The trial is designed to investigate the specificity of C-Tb under various definitions of
      cut-off in a double blind randomised, split-body study comparing 0.1 µg/0.1 mL C-Tb with the
      reference agent 2 T.U. Tuberculin PPD RT23 SSI. (Each volunteer receives the C-Tb agent in
      one arm and the 2 T.U. Tuberculin PPD in the other arm).

      The C-Tb and 2 T.U. Tuberculin PPD agents are given concomitantly to each volunteer in the
      RIGHT AND LEFT forearm according to a double blind randomisation scheme.

      The primary objective of the trial is to assess the specificity of the C-Tb test as a
      function of the cut-off value (i.e., the smallest size of induration measured in mm resulting
      in a negative outcome of the C-Tb test) when the test is administered intradermally by the
      Mantoux technique to healthy BCG vaccinated adults The specificity of the C-Tb test is
      defined as the relative frequency of subjects in a healthy population (i.e., no exposure to
      MTb) who have an induration response < cut-off after a C-Tb test.

      Similarly the sensitivity is defined as the relative frequency of patients with an induration
      response ≥ cut-off in TB patients.

      An optimal cut-off point of being infected will be determined by combing the results from the
      present specificity study with those from a parallel sensitivity study in patients recently
      diagnosed with TB.

      The secondary objectives of the trial are to compare the induration response of C-Tb with the
      induration response of 2 T.U. Tuberculin PPD RT 23 SSI, to compare the induration response of
      C-Tb with the in-vitro IFN-γ response measured at screening and 28 days after the injections
      of the skin test agents using the QuantiFERON®-TB Gold In-Tube assay and finally to record
      all adverse events occurring within 28 days after application of the agents.
    

Intervention name(s): C-Tb; 2 TU Tuberculin PPD RT 23 SSI
Intervention type(s): Biological; Biological
Intervention description(s): The C-Tb agent is administered by the Mantoux injection technique to each volunteer in the RIGHT or LEFT forearms according to a double blind randomisation scheme; The 2TU Tuberculin PPD RT 23 SSI agent is administered by the Mantoux injection technique to each volunteer in the RIGHT or LEFT forearms according to a double blind randomisation scheme
Other intervention name(s): rdESAT-6 + rCFP-10; PPD; Tuberculin
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Diagnostic
Keywords: tuberculosis; rdESAT-6; CFP-10; skin test; diagnostic test