New case of brain illness in Tysabri patient

Another Tysabri patient has contracted progressive multifocal leukoencephalopathy, or PML, a recognised rare complication of Tysabri treatment.

Dr Bill Carroll, Scientific Chairman of MSRA, reassures that "this is the third case since Tysabri was introduced in the US since 2006, and brings the total to five who have developed this complication with Tysabri in trials or open treatment of MS. Around the world over 36,000 people with MS are on the treatment and 18,000 are at 12 months or more. When Tysabri was introduced in Australia the risk of PML was approximately 1:1000 patients. Now it is about 1:3500, which puts this case into perspective."

In response to the cases of PML which occurred during clinical trials, stringent safeguards were instituted by the company Biogen Idec, at the request of the HIC (Australian Government), to detect early symptoms of developing PML.

Treatment depends on the rapid removal of Tysabri from the blood by a process known as plasma exchange, which then allows the immune system to reexert control over the virus responsible for PML. Dr Carroll emphasises that "While this latest case is disappointing, at present the actual risk of development PML is decreasing not increasing".

Tysabri is prescribed for people with relapsing remitting MS and has shown in clinical trials to significant reduce relapses, slow disease progression and reduce the risk of increasing disability.

Anyone concerned should speak directly with their neurologists.

(Source: MS Research Australia: November 2008)