Raptiva is used to control moderate to severe cases of plaque psoriasis, the most common form of the autoimmune disease, which causes red scaly patches on the skin that can itch and hurt.
PML is a serious infection of the nervous system caused by a virus. It's referred to as the JC virus. This virus attacks the brain's white matter and disrupts nervous system activity.
What are the symptoms? Look to where in the brain the virus hits. Common symptoms include deficits in speech, vision, movement and thought processes. The disease progresses rapidly and inexorably toward serious disability and death.
It's important to note that PML is also seen in those with HIV. PML also does not occur without some underlying risk. The highest risk comes from HIV infection.
With Raptiva off the market, is there another treatment for psoriaris?
There is. The drugs Enbrel, Humira and Remicade are medications for its treatment. None has been linked to PML and all three act in a way different from Raptiva.
Sources are here, as well as here and here.