Progressive Multifocal Leukoencephalopathy after Treatment with Nivolumab

Progressive multifocal leukoencephalopathy (PML) is increasingly being reported in patients undergoing immunotherapy. We report a case of progressive multifocal leukoencephalopathy after treatment with nivolumab, a PD-1 blocker that is used to restore impaired T-cell responses in patients with cancer and infections. Data for 4 other cases were obtained from pharmacovigilance databases.