Washout Periods in Inflammatory Bowel Disease Trials: A Systematic Literature Review and Proposed Solutions.

Inflammatory bowel diseases (IBD), encompassing ulcerative colitis (UC) and Crohn's disease (CD), impose a substantial burden. Despite many effective molecules, significant numbers of patients do not achieve clinical remission at 1 year1 and undergo surgery during their lives, revealing an important unmet need and therapeutic gap. Multiple randomized controlled trials (RCTs) are ongoing or planned to develop more effective and tolerable therapies. In parallel, a dramatic decline in recruitment rates has been observed. A multitude of factors have contributed to poor recruitment rates, including a long washout period between the investigational drug and prior advanced therapies (ie, biologic or small molecule drug).2,3 This study aims to review the different washout periods with prior advanced therapies or immunosuppressants in phase 3 RCTs for UC and CD and to propose potential solutions to ultimately improve the design of clinical studies and patient enrollment in future trials.