Clinical trials aim to evaluate benefits of therapeutic or diagnostic procedures for a 'standardized' cohort rather than for individual patients. On the other hand, 'personalized medicine' focuses on the prediction of potential benefits or risks for individuals in as much detail as possible.Currently, clinical trials may still implement the known predictive and/or prognostic factors, as they generally address relatively large groups of patients bearing a well-identified factor and therefore defining an 'enriched' patient cohort. In the near future, as more and more factors for stratification will become available,it is likely that patient cohorts become smaller--hopefully with an increase in the observed effect. Therefore, innovative designs of clinical trials are warranted to integrate the needs of better stratification in smaller patient subsets.
