TABLE V. Expected relative risk reduction depending on the sample size and proportion of patients in the placebo group who reached the primary endpoint per year in the BENznidazole Evaluation for Interrupting Trypanosomiasis (BENEFIT) trial.

Annual event rate (placebo group)	Relative risk reduction depending on sample size
	2000 patients (1000 per group)	2500 patients (1250 per group)	3000 patients (1500 per group)
6%	34.9%	31.3%	28.8%
7%	32.7%	29.6%	27.0%
8%	30.6%	27.6%	25.6%
9%	29.0%	26.5%	24.1%
10%	28.0%	25.4%	23.0%

Calculations assume a two-sided α of 0.05, and a power of 90%. Adapted from Marin-Neto et al. (2008).