Diffusely abnormal white matter in chronic multiple sclerosis.
Seewann A, Vrenken H, van der Valk P et al.
Editor’s note: In this comprehensive and interesting review published in Annals of Neurology, the authors address the risks associated with the newer multiple sclerosis (MS) treatments. The introduction of natalizumab was welcomed by the MS community because of its efficacy compared with existing treatments; however, the emergence of three cases of progressive multifocal leukoencephalopathy (PML) during the treatment trials, and subsequent cases in clinical practice, has made treating physicians acutely aware of the risks associated with using these products and the need for close post-marketing surveillance.