Fig. 2

Sequential testing safety profile. The plot is based on a likely sample size of 75 patients per treatment strategy, a 1-sided α = 0.05, an expected seizure recurrence rate ≤ 30 % and a cut-off point for safety, which is a recurrence rate of ≥ 40 %. The red boundary represents the safety margin. The following formulas will be used to plot data in the graph: Ζ = −(F − n × Pc) (→Ζ = number of observed seizure recurrences – number of expected seizure recurrences), V = n × Pc (1 − Pc) (→V is the variance of Z and stands for the amount of information in n patients, with n being the number of included patients, Pc the expected seizure recurrence risk (i.e., for the selected patient cohort: 0.30) and F the number of observed seizure recurrences). The vertical line is the anticipated value for V for a sample size of 75 patients