Study Suggests Link Between MS Drug and Colorectal Cancer Risk

Patients suffering from multiple sclerosis (MS) should be aware that using the drug mitoxantrone (Novantrone/ Pfizer, Teva) could increase their risk for colorectal cancer.

Typically prescribed for aggressive types of relapsing-remitting or progressive MS that don’t respond to other MS drugs, mitoxantrone’s use is limited since prior studies have linked the drug to increased risks of acute myeloid leukemia (AML) and heart damage, as well.

The drug specifically works by weakening the immune system, reducing the activity of T cells, B cells, and macrophages.

To investigate the correlation between mitoxantrone and other forms of cancer, researchers from Germany studied 676 MS patients who were treated with the drug from 1994-2007, and followed up with then until 2010.

Results showed that 37 of the patients were diagnosed with cancer (upon taking the drug), including nine who were diagnosed with breast cancer, seven with colorectal cancer, and four with acute myeloid leukemia.

Three of the seven colorectal cancer patients died from the cancer during the course of the study.

A total of four AML patients went into remission, but were successfully treated.

The research team highlighted that the rate of leukemia was 10 times higher in the mitoxantrone patient group that in the general population. Also, the rate of colorectal cancer was three times higher in the drug group than in the general population.

However, they found that administration of the mitoxantrone drug didn’t impact the rates of diagnoses for breast and other forms of cancer.

Experts have noted that mitoxantrone is currently the only approved treatment for people with secondary progressive MS without relapses, so it should be considered in patients whose condition is quickly evolving. Mathias Buttman, MD, University of Würzburg in Würzburg, Germany, remarked in a newsletter, “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.”

While the findings need to be tested in a larger study, Buttman suggested that if confirmed, MS patients should undergo colonoscopies after taking mitoxantrone to screen for colorectal cancer.