Serum ferritin levels before and after treatment with deferiprone. The bars labeled “All Patients” represent the mean initial and last values for all patients enrolled in the study, regardless of time on therapy. “Completers” bars represent comparable mean values for patients who completed 4 years of therapy at a daily dose of 75 mg/kg without exposure to deferoxamine. “Interrupted Due To Questionable Effectiveness” bars represent mean initial and last ferritin levels for patients who discontinued therapy with deferiprone because of concerns about the serum ferritin level and/or liver iron concentration. “Interrupted Due To Low Iron” bars represent comparable mean values for patients who interrupted therapy because of ferritin levels lower than 500 μg/L or decreased liver iron concentration.