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MS Agent Mitoxantrone May Be Linked to Colorectal Cancer

May 16, 2016

According to a study, the multiple sclerosis (MS) drug mitoxantrone may be associated with an increased risk of colorectal cancer. The study was published in a recent issue of Neurology, the official medical journal of the American Academy of Neurology.

Mitoxantrone is a drug used to treat aggressive types of relapsing-remitting or progressive MS that fail to respond to other agents. It is often used as a “last resort” as previous studies have linked its use to increased risk of leukemia or heart disease.

The current study examined whether the drug increases the risk of other types of cancer. For the study, German researchers looked at all people with MS who were treated with mitoxantrone from 1994 to 2007 and followed them until 2010.

Of the 676 people, 37 people, or 5.5 percent, were diagnosed with cancer after taking the drug, including nine people with breast cancer, seven with colorectal cancer and four with acute myeloid leukemia, which has been associated with mitoxantrone.

Researchers also looked at whether factors such as how much of the drug people had received cumulatively and whether they also received other immunosuppressant drugs affected their risk of developing cancer. The only factor related to a higher risk of cancer was being older when starting to take the drug.

"Despite an increased risk of acute myeloid leukemia and colorectal cancer, the overall rate of cancer was low enough to justify still using this drug for people severely affected by MS if no better treatment is available," said study author Mathias Buttmann, MD, of the University of Würzburg in Würzburg, Germany. "Mitoxantrone is the only approved treatment for people with secondary progressive MS without relapses and should be considered in people where the disease is evolving quickly. Also, many of the new and highly effective MS drugs are not available to people in a number of countries for economic reasons, so mitoxantrone is being used for people with very active relapsing forms of the disease."