The Food and Drug Administration on Jan. 13 announced that a boxed warning will be added to the label of brentuximab vedotin because of reports of two cases of progressive multifocal leukoencephalopathy associated with the drug's use in lymphoma patients.Brentuximab vedotin (Adcetris) was approved in August 2011 for the treatment of Hodgkin's lymphoma and systemic anaplastic large cell lymphoma. At the time of its approval, the warnings and precautions label described one case of progressive multifocal...