Mitoxantrone is an antineoplastic agent that exerts a potent immunosuppresive effect, including suppression of B cell immunity and reduction of T cell numbers. Clinical trials have shown that mitoxantrone has a statistically significant impact on reduction of relapse rate and delays disability progression in patients with relapsing remitting (RR) multiple sclerosis (MS) or secondary progressive (SP) MS. Treatment is well tolerated, but the risk of cardiotoxicity at higher cumulative doses is likely to limit the duration of treatment. The maximum cumulative dose recommended is 140 mg/m2. In 2000, the FDA (Food and Drug Administration) approved the use of mitoxantrone for the treatment of active RRMS, SPMS and progressing relapsing (PR) MS.