Window of opportunity

A window of opportunity (also called a margin of opportunity or critical window) is a period of time during which some action can be taken that will achieve a desired outcome. Once this period is over, or the “window is closed”, the specified outcome is no longer possible.

Window of opportunity clinical trial designs can provide early insight into the biological plausibility of a novel therapeutic strategy in the clinical setting. A variety of window-of-opportunity trial designs, which take into account the limited access to treated tissue and the challenges with obtaining pretreatment control tissues, have been used for the initial development of traditional and targeted small-molecule drugs and biologic therapies, including immunotherapies and oncolytic viral therapies. Early-stage development of glioma therapeutics should include a window-of-opportunity component whenever feasible ¹⁾.