Efficacy of Bilhvax in Association With Praziquantel for Prevention of Clinical Recurrences of Schistosoma Haematobium
Condition: Urinary Schistosomiasis; Schistosoma Haematobium
MeSH terms: Schistosomiasis; Schistosomiasis haematobia; Recurrence
Study type: Interventional
Phase: Phase 3

Summary: 
      Objectives:To reduce the risk of S. haematobium pathology recurrences during the three years
      following vaccine administration and to control the safety of this therapeutic strategy in
      children exposed to urinary schistosomiasis.

      Methodology : Phase III trial, self-contained, randomized, double blind, in two parallel
      groups receiving 3 injections at D0, W4, W8 and a boost at W52, one group receiving
      "Bilhvax", the other one placebo, in S. haematobium infected children pretreated by two doses
      of PZQ (at W9 and W8) Patient included : Infected school children, 6 to 9 years of age.

      Primary objective : To demonstrate a significant delay of recurrence of the schistosomiasis
      pathology in vaccine group compared to control group in the 3 years period following the
      first administration (between D0 and W152).

      Secondary objective : safety

      Duration : February 2009 to March 2012
    

Detailed description: 
      Patient inclusion (detailed criteria):

      Children in CI or CP classes of public schools in St Louis Region (Senegal) A male or female
      between, and including, 6 and 9 years of age at the time of the first vaccination Free of
      obvious health problems excepted schistosomiasis as established by clinical examination
      (W8-W1) Found positive for S. haematobium infection during the selection period (W12 à W9) :
      microhaematuria ≥ 2+ et Urinary Filtration, UF ≥ 50 eggs of Sh/10ml urine Written inform
      consent obtained from the parent or guardian of the subject (W9) and child acceptance
      Pretreated with 2 doses of 40mg/kg PZQ (at W9 and W8) Absence of heavy lesions of the urinary
      tract under echotomography (W8 et W1)

      Primary objective (detailed):

      To demonstrate a significant delay of recurrence of the schistosomiasis pathology in vaccine
      group compared to control group in the 3 years period following the first administration
      (between D0 and W152).

      Criterion of meeting the recurrence is the association of :

      Positive microscopic haematuria (positivity by urinary stick : ≥ 1+)

        -  either during the active visits (W82, W100, W117, W134, or W152).

        -  or after spontaneous complaint of the patient at any time Positive parasitological test
           defined as the presence of at least one living egg of S. haematobium during one out of
           three UF (one UF per day/3 days during one week). The delay of the first recurrence is
           defined as the delay between the date of inclusion and the date of the positive
           parasitological test.

      Statistical considerations : The number of patients necessary to detect the expected
      difference after 3 years of study (50% of recurrence in vaccinated group versus 70% in
      placebo group), with a statistical power of 80% and a bilateral test at 5%, is 103 children
      per group. To assume the lost of statistical power in the "intention to treat" analysis (ITT)
      resulting from the number of cases where vaccine protocol has not been completed, 125
      children per group will be included in the study. In total 250 children will be included in
      the study.
    

Intervention name(s): Bilhvax vaccine (Sh28GST); placebo
Intervention type(s): Biological; Biological
Intervention description(s): Four vaccine sc administrations over a year associated with chemotherapy (PZQ); Four placebo sc administrations over a year associated with chemotherapy (PZQ)
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Prevention
Keywords: Schistosomiasis vaccine; therapeutic vaccine; Bilhvax