What role can decentralized trial designs play to improve rare disease studies?

People affected by rare diseases want to be involved in research and the search for new treatments. Randomized controlled trials remain the best way of finding new interventions, but many elements of traditional study design are not best suited for rare diseases. Barriers to patients and families include the use of specialist hospital sites for recruitment, requiring frequent site-based study visits for data collection, and a high burden of tests and outcome measures in research. While decentralized clinical trial (DCT) designs have been developed in some rare disease trials, changes necessitated by the COVID-19 pandemic present an opportunity for them to become a standard approach. DCT approaches have been shown to be more resilient to changes in enrolment and attrition during COVID-19 than traditional designs and offer benefits in terms of patient burden, convenience, inclusion, and data quality. Digital tools such as wearable devices and electronic clinical outcome assessments may also provide more convenient and environmentally valid measures of how a condition affects the life of an individual in their regular environment (e.g. mobility around the home versus a hospital corridor). Digital solutions have greater ability to support language localization, accessibility, and may lead to increase access to global rare disease trials. In parallel, challenges exist, such as the technical support, the digital divide, ensuring high quality data, and delivering safe trials.