Mitoxantrone-Associated Leukemia in Multiple Sclerosis: Case Studies

This article describes four new cases from our clinical practices of therapy-related acute leukemia after use of mitoxantrone in the treatment of patients with multiple sclerosis (MS) and reviews the mechanisms that predispose to this serious complication of treatment. The study consisted of a retrospective case series. Four previously unreported cases of secondary leukemia arising after mitoxantrone therapy in MS patients were identified, out of a combined cohort of 152 patients treated at our institutions. Three of the patients developed the acute promyelocytic leukemia subtype, after varying doses and latencies of mitoxantrone therapy. One of the study patients died. Characteristics of these patients and 10 previously reported cases are summarized. MS patients treated with mitoxantrone remain at risk for therapy-related leukemia, particularly acute promyelocytic leukemia. Strategies for minimization and prompt identification of this adverse event are needed.