Mitoxantrone-related acute leukemia in two MS patients.

We report two new cases of mitoxantrone-related leukemia occurring in two patients with multiple sclerosis (MS), 14 and 18 months after the last infusion of the drug. One patient was successfully treated. We were able to collect 29 other cases in the literature. Most of them were single reports but some were described within cohorts of mitoxantrone-treated MS patients. The incidence rate was 0.65% from all cohorts totalizing 2299 patients. Acute promyelocytic leukemia with the translocation t(15;17) was over-represented in the MS population in comparison with cancer patients also treated with mitoxanrone. The occurrence of leukemia was dose-independent and appeared with a mean delay of 20 months after the end of the treatment.