Dr Clifford’s career has focused on improving therapeutics for neurological disorders, with a particular focus on translational clinical trials. With the HIV epidemic, he turned his attention to HIV and its complications, working in the AIDS Clinical Trials Group, an NIH funded international group developed to address the AIDS epidemic. Since 1993, I developed and led the Neurologic AIDS Research Consortium, an NIH funded national research group designed to develop improved therapy for neuroAIDS complications. It was first in this setting he turned his attention to progressive multifocal leukoencephalopathy (PML), helping develop a clinical trial for cytarabine as well as cidofovir through this network. He is the Principal Investigator of the AIDS Clinical Trials Unit at Washington University, the Washington University Site PI of the CHARTER Aging study. He is also the Principal Investigator for the Washington University NeuroNEXT trial unit, one of 25 centers funded by NIH (NINDS) and designed to accelerate Phase 2 clinical trials for neurological disorders. He was principal investigator for the Biogen funded study of mefloquine as a therapy for PML. He has led international research relevant to HIV and the nervous system in Ethiopia, Uganda, The Gambia, Guinea Bissau, and Senegal. Recently, he has turned attention to therapeutic trials for Alzheimer disease, serving as Medical Director for the Dominant Inherited Alzheimer Disease Treatment Unit (DIAN-TU). Progressive multifocal leukoencephalopathy (PML) has been a disease of special interest since the HIV epidemic began, and Dr. Clifford was active in the independent adjudication panel for patients exposed to natalizumab. He has consulted widely regarding risk and management of PML.