Tecfidera is a prescription drug used to treat people with relapsing forms of multiple sclerosis, a disease where the immune system eats away at the protective covering of nerves. Last month Biogen Idec, manufacturer of Tecfidera, reported a patient developed progressive multifocal leukoencephalopathy (PML), a rare brain infection, and died. Although Biogen Idec stated the safety profile of the drug remained solid, the FDA decided the death was important enough to add a description of it on Tecfidera labels.
PML is a rare and usually fatal viral disease caused by the John Cunningham (JC) virus. PML is characterized by progressive damage or inflammation to the white matter of the brain at multiple locations. PML is rare since the JC virus, which is relatively common, is typically harmless except in cases of weakened immune systems.
The patient who developed PML and died was not taking other drugs that affect the immune system nor drugs that are associated with PML. According to the FDA this is the only confirmed case of a PML death reported in Tecfidera users. The European patient, who ultimately died of pneumonia, had been taking Tecfidera for four years beginning during clinical trials.
Similarly, Biogen's infused MS drug Tysabri, was linked to several cases of PML. Tysabri was taken off the market soon after its launch because several patients developed PML. It returned the next year with a risk-management program and prescribing restrictions. Although MS drugs may present significant risks, patients often agree to run the risks to prevent the debilitating effects of MS.