Etiologic Treatment With Benznidazole in Adult Patients With Chronic Chagas Disease. A Randomized Clinical Trial

Overview

The purpose of this study is: 1. -to determine whether benznidazole (BZN) will be able to modify the natural evolution of chronic Chagas disease in adult patients by means of a randomized, double-blind clinical trial (RCT). Also: 2. -to validate therapeutic efficacy with new methods, such as recombinant antigen F29 of Trypanosoma cruzi visualized by conventional ELISA, in the context of the RCT compared with conventional serology (CS) 3. -to develop the real-time polymerase chain-reaction (RT-PCR) to quantify the parasite load as an early therapeutic effect. 4. to determine the potential of such serological and parasitological methods as predictors of therapeutic effect or failure.

Patients and Methods. Patients selected to be enrolled were born in Chagas disease endemic areas of Argentina and bordering countries such as Bolivia and Paraguay, whose current residence is in urban non endemic areas of Argentina. They were sorted by clinical stage: stage 0, 1, 2 and 3 according to a modified Kuschnir classification.1 Briefly, Stage 0 corresponds to patients only with reactive serology for Chagas disease; stage 1, patients with reactive serology plus electrocardiographic abnormalities; stage 2, patients with the abovementioned characteristics plus dilatation of left ventricle by echocardiography, and stage 3, patients with the abovementioned characteristics, plus cardiac failure. The follow-up was performed every 4 months during the first 2 years, every 6 months in the 3rd and 4th year, and annually from then on until the end of the study in 2012. The safety of TRAENA was controlled at days 25 and 45 intra-treatment by means of laboratory tests and clinical evaluation, and at any time that an adverse event was apparent in patients. Adherence to medication administration was verified by means of a booklet where the patient recorded the daily intake of medication and any physical abnormality that appeared during the time they were taking of medicine. Adherence was controlled by a surveillance and recovery system which consisted of telephone calls, telegrams, letters or home visits that was termed "active monitoring", which was immediately applied to the control visit when the patient did not attend the corresponding schedule control. Telephone calls were the most useful tool to recover adherence to monitoring. Patients were assigned to BZN or Placebo treatment by an investigator independent from the research group. Prior to randomization, a pre randomization stratification was performed according to prognostic factors based on clinical stages of Chagas disease. A database was designed to be used as the registry for the whole study. Demographic, epidemiologic, serologic, parasitological and clinical variables were used in its design, and were registered pre treatment, intra treatment and post treatment throughout the monitoring. Medical records were the primary documents for the registry, where all the variables were recorded manually. Based on the data, variables were registered on a daily basis and a random weekly check was conducted on the data against the medical records. Our Standard Operating Procedure was based on the following procedures: patient screening, selection and coding, sample collection, serum bank, DNA sample storage, monitoring systematization, surveillance systems to recover patients who had discontinued monitoring, etc. In October 2011 the Base Data Monitoring Board for the last Interim Analysis, recommended an addendum modifying the secondary outcomes, adding simple and combined events. These events were characterized only by electrocardiographic abnormalities or associated to echocardiographic ones. These events were evaluated up April 2013.