In the Mitoxantrone in Multiple Sclerosis (MIMS) study, patients were enrolled between 1993 and 1997 at 17 centers in Belgium, Germany, Hungary, and Poland, and randomly assigned to treatment with mitox. Cardiac monitoring, electrocardiography (ECG), and left ventricular ejection fraction (LVEF) assessed by echocardiography or radionuclide scan, was performed before treatment. The comparative study of mitox efficacy profile in relapsing-remitting multiple sclerosis (RRMS) and secondary-progressive multiple sclerosis (SPMS) evaluated the clinical and neuroradiological response to mitox. Substantial tolerability data are available from oncology studies in which mitox was generally used in combination with cyclophosphamide, luorouracil, mitomycin, methotrexate, and radiotherapy for leukemia, non-Hodgkin's lymphoma and solid tumors, and from MS studies in which mitox was used as monotherapy. The available data from studies in patients with MS suggest that mitox may have a role to play in the management of aggressive disease, as an induction therapy.