Linking clinical trial participants to their U.S. real-world data through tokenization: a practical guide

In drug development, the use of real-world data (RWD) has augmented our understanding of patients' health care experiences and the effects of treatments beyond clinical trials. Although electronic health record (EHR) data integration at clinical trial sites is a widely adopted practice, primarily for recruitment and data capture, a challenge to data utility is the fragmentation of health data across different sources. Linking RWD sources to each other and to trial data -- while preserving patient privacy through tokenization -- aids in filling evidence gaps with outcome data and facilitates the generalization of effects from controlled trial environments to real-world settings. This paper describes the applications of RWD linkage and how they benefit both clinical development and real-world decision-making. Trial benefits include improving interpretability and generalizability (e.g., by remediating missing data or losses to follow-up), extending follow-up beyond trial closeout, and characterizing the applicability of trial results to under-represented groups. The operational aspects of linking trial data to RWD are addressed, emphasizing the importance of using privacy-preserving record linking systems with established metrics of accuracy and precision, managing consent, and providing the necessary training and resources at trial sites to inform participants about providing access to their RWD through data linkage.