News

The New England Journal of Medicine has published two reports from Europe of people with psoriasis who developed progressive multifocal leukoencephalopathy (PML, a viral infection of the brain that usually leads to death or severe disability) while taking fumarate-based treatments. It has not been proven that the treatment caused the infection. No such cases have been reported in people with MS taking the related product, Tecfidera™ (dimethyl fumarate, Biogen Idec), which was approved earlier this year to treat relapsing MS. The case reports appear along with a response from Biogen Idec staff in the April 25, 2013 issue (NEJM 368;17;1657-60).

One case occurred in a 74-year-old man in Germany who had taken Fumaderm® (fumaric acid esters, Biogen Idec) for three years. Fumaderm is chemically related to Tecfidera and has been used for decades in Germany to treat acute flare-ups of psoriasis). Previously he had taken immune-suppressing medications, a risk factor for the development of PML. The other case occurred in a 42-year-old woman in The Netherlands who took Psorinov (compounding pharmacy, Mierlo-Hout) which contains dimethyl fumarate and other ingredients. She had not taken immunosuppressants previously.

Both individuals had experienced prolonged periods of abnormally low levels of white blood cells (lymphocytopenia) while on treatment. These cells help the body fight infections. Having deficient immune system activity is a risk factor for PML. Prescribing information for Fumaderm recommends discontinuing treatment if a person develops lymphocytopenia. The case studies report that both patients improved after stopping Fumaderm therapy and treating PML.

In a published response to the case reports, Biogen Idec medical staff note two additional reports of PML occurring in people taking Fumaderm for psoriasis, who exhibited other significant PML risk factors, such as prior use of immunosuppressants. They comment that, “On the basis of more than 180,000 patient years of experience with Fumaderm, reports of PML are rare.” They also point out that in clinical trials of Tecfidera, more than 2,600 people with MS were treated for up to 4 years or more, with no evidence of increased risk of serious infections or PML.

In clinical trials, Tecfidera was found to reduce white blood cell counts but no significant or severe infections were reported. According to prescribing information, before starting treatment with Tecfidera, it is recommended that a person’s health care provider assess a recent (within 6 months) blood cell count, and repeat the blood cell count annually thereafter.

Read more about Tecfidera.