11th Tysabri Patient Develops PML

Main Category: Multiple Sclerosis
Also Included In: Neurology / Neuroscience
Article Date: 29 Jul 2009 - 3:00 PDT

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An 11th patient taking Biogen Idec's multiple sclerosis (MS) drug Tysabri has developed a potentially deadly brain infection.

In the latest confirmed case of progressive multifocal leukoencephalopathy, or PML, the patient took Tysabri for 29 doses, continuing the trend of the last six reported cases of the infection, where each patient had therapy for two years or longer.

The latest patient was located in the USA, the third American to have developed the infection. Of the 11 reported cases, one patient has died.

The PML incidence rate remains below the long-projected risk rate of one in 1,000 patients for those patients receiving the therapy for 12 months or 18 months.

The drug was temporarily withdrawn in 2005 after it was linked with PML, but was then brought back in 2006 with stricter safety warnings.

Tysabri continues to receive strong support from patients and doctors, however, because of the drug's perceived effectiveness. That support has remained steady because patients are made well-aware of the PML risk before they start taking Tysabri for MS.

This is the last case of PML that the company plans to announce on its website. In future any new cases will be reported by word of mouth to medical professional and patient groups.

Source
Multiple Sclerosis Society

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