Washout period for immune-modifying drugs before natalizumab therapy

摘要

This is a follow up to an AJHP article on natalizumab. Our intent is to emphasize the safety issues associated with the use of the drug. Marketing approval of natalizumab was initially granted by the Food and Drug Administration (FDA) in November 2004, but the drug was withdrawn by the manufacturer in February 2005 after three patients in the drug's clinical trials developed progressive multifocal leukoencephalopathy (PML). Although the cases of PML were limited to patients with recent or concomitant exposure to immunomodulators or immunosuppres-sants, there were too few cases to rule out the possibility that PML may occur with natalizumab monotherapy.