Ethics review of decentralized clinical trials (DCTs): Results of a mock ethics review

•Ethics review of DCTs emphasizes potential risks and burdens.•Risk-aversiveness may invoke overregulation.•We recommend to observe impact of changing practice while giving some room to DCTs.•Build evidence on DCTs to promote evidence-based review practice. Decentralized clinical trials (DCTs) can be a valuable addition to the clinical trial landscape. However, the practice of DCTs is dependent on a regulatory system designed for conventional (site-based) trials. This study provides insight into the ethics review of DCTs. A ‘mock ethics review’ was performed in which members of European ethics committees (ECs) and national competent authorities (NCAs) discussed and reviewed a DCT protocol. Respondents expressed hesitancy toward DCTs and focused on potential risks and burdens. We advise to address these aspects explicitly when submitting a DCT protocol. We propose that both the benefits and risks of DCTs should be carefully monitored to advance the review and practice of this innovative approach to ethically optimize drug development.