Influence of Trimethoprim-Sulfamethoxazole for the Recurrence of Ocular Toxoplasmosis
Condition: Ocular Toxoplasmosis
MeSH terms: Toxoplasmosis; Toxoplasmosis, Ocular; Recurrence
Study type: Interventional
Phase: Phase 3

Summary: 
      The investigators study aims to determine the effect of prophylactic therapy with
      Trimethoprim-sulfamethoxazole on the recurrences of toxoplasma retinochoroiditis gondii. This
      is a randomized, double-masked, in patients with eye condition of acute Toxoplasma gondii
      retinochoroiditis. Volunteers will be recruited with a previous diagnosis of chorioretinitis
      presumed Toxoplasma gondii, which show active lesions compatible with recurrence. After the
      acute phase of treatment of all patients [1 tablet Trimethoprim-sulfamethoxazole (800/160mg)
      12/12h during 45 days], the same Stratified by gender) will be randomized in a 1:1 ratio
      between the group 1 - TMP-SMZ (prophylactic treatment with trimethoprim-sulfamethoxazole 1
      tablet every other day for 311 days) or group 2 - placebo (consisting of a placebo pill
      containing no active ingredient of similar appearance to trimethoprim-sulfamethoxazole, 1
      tablet every other day for 311 days). The primary outcomes are incidence of episodes of
      recurrent chorioretinitis by toxoplasmosis in the follow up of 12, 36, 48, 60, 72, 84, 96,
      108, and 120 months. Patients will be followed during the ten years in uveitis clinic at
      intervals defined as follows: return weekly for 4 weeks, then monthly for 2 months, then each
      3 months for 9 months, and finally annually for 10 years.
    

Detailed description: 
      The protozoan Toxoplasma gondii is an obligate intracellular parasite, a common cause of
      intraocular inflammation in the world. The treatment of toxoplasmosis is the sulfonamide
      group of drugs, which acts on tachyzoites forms, no acting on bradyzoites, that grown from
      latent focus located on boards and are responsible for recurrence. The investigators study
      aims to determine the effect of prophylactic therapy with Trimethoprim-sulfamethoxazole on
      the recurrences of toxoplasma retinochoroiditis gondii. This is a randomized, double-masked,
      in patients with eye condition of acute Toxoplasma gondii retinochoroiditis. The study
      population consists of patients treated at Ophthalmology department, University of Campinas.
      They present symptoms compatible with a diagnosis of recurrent ocular toxoplasmosis.
      Volunteers will be recruited with a previous diagnosis of chorioretinitis presumed Toxoplasma
      gondii, which show active lesions compatible with recurrence. After the acute phase of
      treatment of all patients [1 tablet Trimethoprim-sulfamethoxazole (800/160mg) 12/12h during
      45 days], the same Stratified by gender) will be randomized in a 1:1 ratio between the group
      1 - TMP-SMZ (prophylactic treatment with trimethoprim-sulfamethoxazole 1 tablet every other
      day for 311 days) or group 2 - placebo (consisting of a placebo pill containing no active
      ingredient of similar appearance to trimethoprim-sulfamethoxazole, 1 tablet every other day
      for 311 days). The definition of a patient with recurrent episode of chorioretinitis
      Toxoplasmosis is the presence of old scars of chorioretinitis, associated with satellite
      active lesions chorioretinitis with positive IgG for toxoplasmosis. The new recurrence was
      treated with 1 tablet Trimethoprim-sulfamethoxazole (800/160mg) 12/12h during 45 days. The
      patients will be tested for visual acuity, examination biomicroscopy, tonometry, fundus
      photography and indirect ophthalmoscopy. In each study, patients will be randomized in blocks
      of four (two in group I and two Group II) with stratification by gender. The primary outcomes
      are incidence of episodes of recurrent chorioretinitis by toxoplasmosis in the follow up of
      12, 36, 48, 60, 72, 84, 96, 108, and 120 months. It was planned a minimum sample of 140
      patients (70 in group I and 70 in group II). Assuming an incidence of 6% recurrence in group
      A, this sample will have a 80% power to detect a difference of 18% between groups. The
      results of this analysis will be considered significant if p <0.05. The main variables are
      age, sex, presence of unilateral or bilateral eye injury, number of recurrences, number and
      location of lesions, and previous treatment for ocular toxoplasmosis. Patients will be
      followed during the ten years in uveitis clinic at intervals defined as follows: return
      weekly for 4 weeks, then monthly for 2 months, then each 3 months for 9 months, and finally
      annually for 10 years. Patients will be trained to return immediately if they have any of the
      following symptoms: decreased visual acuity, photophobia, floaters or ocular hyperemia.
      Adverse events will be monitored. The definition of a patient with a recurrent episode of
      chorioretinitis Toxoplasmosis is the presence of old scars of chorioretinitis, associated
      with active satellite lesions chorioretinitis with positive IgG for toxoplasmosis. To data
      collection, will be used semi-structured questionnaire, containing the patient record, age,
      gender, visual acuity by ETDRS chart, the affected eye and previous treatment for ocular
      toxoplasmosis.
    

Intervention name(s): Trimethoprim-Sulfamethoxazole
Intervention type(s): Drug
Intervention description(s): Sulfamethoxazole 800mg + Trimethoprim 160mg / tablet. In treatment of acute phase, 1 tablet 12/12h 45 days. After acute phase, 1 tablet every other day, morning, 311 days. Placebo tablet - Composition: starch. After acute phase, 1 tablet every other day, morning, 311 days.
Other intervention name(s): Sulfamethoxazole 800mg + Trimethoprim 160mg = Bactrim F.
Intervention MeSH terms: Trimethoprim; Trimethoprim, Sulfamethoxazole Drug Combination; Sulfamethoxazole
Allocation: Randomized
Intervention model: Single Group Assignment
Masking: Triple (Participant, Care Provider, Investigator)
Primary purpose: Prevention
Keywords: Ocular Toxoplasmosis; Retinochoroiditis; Prophylaxis