Evaluation of Patients Treated with Natalizumab for Progressive Multifocal Leukoencephalopathy

Abstract

Progressive multifocal leukoencephalopathy (PML) is a demyelinating disease of the central nervous system that is encountered most frequently in the setting of immunodeficiency.1 The disease is caused by the human polyomavirus JC virus, a common and widespread infection in humans. PML was reported in three patients who received natalizumab (Tysabri, Biogen Idec and Elan Pharmaceuticals).2–4 Natalizumab is a recombinant humanized antibody directed to the α4 integrins, both α4β1 and α4β7.5 The drug was approved by the Food and Drug Administration (FDA) for the treatment of relapsing forms of multiple sclerosis in . . .