Compounds that modulate the oxidoreductase enzyme indoleamine 2,3- dioxygenase, and compositions containing the compounds, are described herein. The use of such compounds and compositions for the treatment and/or prevention of a diverse array of diseases, disorders and conditions, including cancer- and immune-related disorders, that are mediated by indoleamine 2,3-dioxygenase is also provided.Linvention concerne des composés qui assurent la modulation de lenzyme oxydo-réductase indoleamine 2,3-dioxygénase, ainsi que des compositions contenant ces composés. Linvention concerne également lutilisation de tels composés et compositions dans le traitement et/ou la prévention dun ensemble varié de maladies, troubles et affections, y compris de troubles liés au cancer et à limmunité, à médiation par lindoleamine 2,3-dioxygénase.