An Italian study confirms that people with multiple sclerosis (MS) who are treated with the drug mitoxantrone have an increased risk of developing acute leukemia. Furthermore, it seems that the risk is significantly higher than previously reported.

"The potential risk of acute leukemia should be carefully considered against the potential benefits of mitoxantrone treatment in every single patient," Dr. Vittorio Martinelli of the Multiple Sclerosis Center, University Vita-Salute, Milan, advised in a statement at a meeting in Seattle of the American Academy of Neurology.

Mitoxantrone, known by the brand name Novantrone or DHAD, is approved by the US Food and Drug Administration for the treatment of aggressive relapsing-remitting MS.

Previous studies have linked treatment with mitoxantrone with an increased risk of acute leukemia. According to those studies, acute leukemia occurred in 0.07 percent to 0.25 percent of MS patients taking mitoxantrone.

However, in a retrospective study of 2854 Italian patients with MS receiving the drug, Martinelli's group found that 21 — or 0.74 percent — developed acute leukemia, 8 of whom died.

Acute leukemia developed an average of 37 months after the start of mitoxantrone and an average of 18 months after the end of treatment.

"It is vital that all MS patients treated with mitoxantrone undergo prolonged and careful hematological follow-up to check for acute leukemia," Martinelli advised.