Overview of included patients. A total of 648 patients were eligible for this study. Of these, 17 patients were eligible but were not yet included in the study, and 25 patients were excluded by the centers' investigators for various reasons. Baseline data were available in 606 patients (93.5%). Of these 606 patients, 6 were not treated with FVIII products during the study period, 15 had an unknown inhibitor status because of unavailable data, 59 were treated on less than 75 exposure days (median, 18 days; IQR, 7-36 days; range, 1-69 days), 179 had development of clinically relevant inhibitors, and 347 patients were treated with FVIII on 75 exposure days without the development of inhibitors.