German Study Suggests Leukemia and Colorectal Cancer Rates Increased with Mitoxantrone Use for MS

Summary

• A study of 676 people with MS treated with the MS therapy mitoxantrone in Germany reveals that the rates of acute myeloid leukemia (a type of cancer) and colorectal cancer were significantly increased above what would be expected in the general population there. Rates of other cancers were not increased.
• The authors note that if the findings are confirmed, recommending colonoscopy after treatment may be advisable, since if found early enough, colorectal cancer is curable.
• The team (led by Dr. Mathias Buttmann, University of Würzburg, Germany) has published results in Neurology (published early online, May 11, 2016).

Details
Background: Mitoxantrone is a powerful immune-suppressing therapy. Prior to its approval for use in MS, it was used only to treat certain forms of cancer. It acts in MS by suppressing the activity of immune T cells, B cells, and macrophages that are thought to lead the attack on nerve-insulating myelin. The U.S. Food and Drug Administration approved mitoxantrone for reducing neurologic disability and/or the frequency of relapses in people with secondary progressive MS or worsening relapsing-remitting MS. The total lifetime dose is limited to avoid possible heart damage. Acute myeloid leukemia has been previously reported in people treated with mitoxantrone for MS or cancer.

The Study: Investigators identified 677 people with MS seen at the University of Würzburg MS center between January 1994 and December 2007 who had received mitoxantrone. They were able to follow up with 676 of these patients.

The results show that 37 people developed cancer after taking mitoxantrone, including nine cases of breast cancer, seven cases of colorectal cancer, and four cases of acute myeloid leukemia. The rate of acute myeloid leukemia was 10 times that seen in the general population in Germany. The rate of colorectal cancer was three times that seen in the general population in Germany. The rate of breast and other cancers was not increased over that seen in the general population in Germany. Older age at treatment was associated with increased risk of cancer, but not prior use of other immunosuppressive treatments, or duration of treatment with mitoxantrone.

The team (led by Dr. Mathias Buttmann, University of Würzburg, Germany) has published results in Neurology (published early online, May 11, 2016).

Comment: The authors state that if the findings are confirmed, “posttreatment colonoscopy might improve the risk-benefit ratio of this highly active immunosuppressive drug,” since if found early enough, colorectal cancer is curable. They also note that mitoxantrone is currently the only MS therapy approved for treating secondary progressive MS, and that the overall rate of cancers may still justify the use of mitoxantrone in people who are severely affected with MS and where there are no better treatment options available.

Read more about mitoxantrone
Read more about treating secondary progressive MS
Read more about making treatment decisions in MS