TL39: Crossover Design in Clinical Studies
*Steven Bai, U.S. Food and Drug Administration  *Tao Wang, Eli Lilly and Company 

Keywords: crossover design, clinical trial, carryover effect, switch treatments, washout period, baseline selection

For decades, crossover design has been widely applied to pharmaceutical studies, such as PK/PD, bioequivalence, medical device (preference and safety endpoints), and all-phase clinical trials. However, in spite of the unique benefits crossover studies can bring to patients (e.g. evaluate safety/efficacy when patients switch treatments); discussions about its applicability and interpretability are still an on-going effort among academia, industry, and regulators, especially for late-phase clinical trials. We will take this opportunity to discuss key topics including suitable disease states and patient populations, carryover effect, washout period, baseline selection, proper/novel analysis methods, benefit/risk evaluation, and the design's future in clinical studies to help patients. Any other relevant topics are welcome to be brought to the table as well.