Biogen Idec Inc.’s Fumaderm, an early formulation of the company’s just approved multiple sclerosis pill Tecfidera, was tied to three cases of a brain infection more often linked to its potent medication Tysabri.
Fumaderm has been sold in Germany for almost two decades to treat psoriasis. All three patients had the skin condition and risk factors for the brain disease known as progressive multifocal leukoencephalopathy, doctors said. The three cases were disclosed in letters today to the New England Journal of Medicine, along with a fourth case in a psoriasis patient given a pharmacy-made drug including Tecfidera’s active ingredient.
The risk deserves attention since other medicines with the same active ingredients are emerging and may be used to treat a broader range of ailments, said one set of researchers from VU University Medical Center in Amsterdam. Three years of fumaric acid was probably an important factor in the development of the brain infection known as PML in one 74-year-old patient, said researchers led by Ummehan Ermis from Rheinisch-Westfalische Technische Hochschule Aachen, in Aachen, Germany.
“Long-term treatment with fumaric acid and prior treatment with other immunosuppressants may have increased this patient’s risk of PML,” the researchers wrote. Before implicating the drug’s ability to depress white blood cell counts as the probable reason for the infection, “we ruled out other causes of immunodeficiency and cancer,” they said.
There haven’t been any cases of PML in 2,600 patients treated with Tecfidera, including those who have been on the drug for four or more years, said Kate Niazi-Sai, a Biogen spokeswoman, in a telephone interview. The company provided the U.S. Food and Drug Administration information about the cases before the drug won approval, and the agency raised no concerns, she said.
While Fumaderm is known to reduce levels of infection-fighting white blood cells known as lymphocytes, severe depletion occurs in only about 3 percent of cases, Biogen officials said in a letter in the journal. Patients with low lymphocyte levels should be taken off the drug. In the two cases detailed in the journal, one patient had depressed levels for two years and the other for five years before PML was diagnosed.
Fumaderm and Tecfidera are “chemical cousins,” not identical copies, said Eric Schmidt analyst at Cowen & Co. in New York. Many psoriasis patients in Germany get the Tecfidera “look-a-like” drug, he said.
“I think people are going to shake this thing off,” Schmidt said. “It’s old data and not relevant to Tecfidera, given that it’s not the same drug. There are confounding variables,” he said. The patients were taking other medications as well, and had “diseases that might have predisposed them to develop PML to begin with,” he said.