Statistical analyses
Analysis of patient characteristics used the full analysis set (FAS), which included all patients who received at least one dose of study drug. For analysis of ELISA F29, a subpopulation was defined that included all patients in the FAS who had positive ELISA F29 results at baseline.The incidence rate of seronegative conversion measured and confirmed by ELISA F29 in patients from the FAS was calculated. Incidence rate is the number of new cases of seronegative conversion over the study period, i.e. 4 years after end of nifurtimox treatment, divided by the total number of person-years, which was the estimate of the actual number of at-risk years for all patients who contributed to the study. Patients who used antitrypanosomal drugs other than the study drug before they were seroconverted to negative were not considered as seroconverted, but their time of observation until the first use of antitrypanosomal drugs was factored into the person-time calculation.All analyses were descriptive, and no formal testing was performed. All statistical analyses were performed using Statistical Analysis System version 9.2 or higher (SAS Institute, Cary, NC, USA).