Chronic progressive multiple sclerosis (MS) is a debilitating disease that is often refractory to treatment. We have previously published a pilot study using a single 2-week course of the iron chelating drug, desferrioxamine (DFO), as a candidate drug for treatment of this form of MS. In this study, we gave 9 patients up to 8 courses of this regimen over 2 years. The patients tolerated the medication well. During the study, 1 patient improved, 3 remained stable, and 5 worsened by 0.5 on the Kurtzke expanded disability status scale (EDSS). These results suggest that, while the drug is well tolerated, no effect on disease progression can be identified at this dosage level. A more continuous dosage schedule could be studied as a candidate for treatment in this disease process.