“The ground is shifting in terms of how we will continue using randomized clinical trial data and real-world data in many different disease settings,” says Veronica Miller, co-author of Use of External Controls in FDA Regulatory Decision Making. In this research article, Miller (Forum for Collaborative Research) and Adora Ndu (Bridgebio Pharma, Inc.) describe where and how FDA has used external controls to support development and approval of drugs for rare and pediatric diseases. “We're seeing, not just in rare diseases but in many other diseases, this coming together of what used to be totally separate silos. In part, that's facilitated through electronic health records and other mechanisms of capturing data and being able to follow data at a bigger level, but also just because of understanding the importance of clinical data.”