Tecfidera Linked to Case of PML Brain Infection

A patient taking the multiple sclerosis drug Tecfidera has died of a rare brain infection, known as progressive multifocal leukoencephalopathy (PML), which has plagued a number of similar drugs that work by lowering the immune system response. 

The drug maker Biogen announced on Wednesday that an unidentified patient died from a PML brain infection after taking Tecfidera, the first known case associated with the medication.

Progressive multifocal leukoencephalopathy (PML) is a rare and often deadly brain infection that is believed to be caused when some immunosuppressant drugs disable the immune system enough for the JC virus to take hold. The JC virus then attacks brain tissue, causing cognitive brain problems, motor control and speech problems, and in many cases results in death.

The infection problems have been linked to other MS drugs, including Biogen’s Tysabri, which was recalled shortly after it was introduced in 2004 and then re-introduced in 2006 with stricter guidelines for usage due to the risk of PML. At least 400 cases of PML have been linked to Tysabri, about a quarter of whom have died from the ailment.

Until now, Tecfidera had not been associated with PML. Other drugs associated with the brain infection, such as Tysabri and Gilenya, have been restricted by the FDA, and it is unclear whether Tecfidera will face new restrictions following the latest development.

Even though there were no recorded previous cases, Tecfidera already carried a PML warning, noting that it was a likely side effect of how the drug suppressed the immune system, so it is unclear whether the FDA will see a need to take action.

Tecfidera (dimethyl fumarate) is an oral multiple sclerosis treatment approved by the FDA in March 2013. It is specifically approved for MS patients suffering relapses. Biogen has warned that PML may be more likely in patients suffering low white blood cell counts, and the patient who died of PML while taking the drug fell into that parameter, company officials said.