Predicting Risk of Progressive Multifocal Leukoencephalopathy from Natalizumab

After a century of futility in the treatment of multiple sclerosis, there is now a deluge of drugs that alter the course of the disease. The half-dozen new oral drugs have excited the most interest, but the monoclonal antibodies, and specifically natalizumab, have a more focused biologic activity and are more potent. It is ironic that natalizumab can cause not just a second neurologic disease, progressive multifocal leukoencephalopathy (PML), but one that, like multiple sclerosis itself, affects the oligodendrocytes and central nervous system myelin.Once it was apparent that PML was related to natalizumab treatment, and the drug was withheld . . .