Randomized controlled trials (RCTs) are the cornerstone of modern evidence-based medicine. They are considered essential to establish definitive evidence of efficacy and safety for new drugs, and whenever possible they should also be the preferred method for investigating new high-risk medical devices. Well-designed studies robustly inform clinical practice guidelines and decision-making, but administrative obstacles have made it increasingly difficult to conduct informative RCTs. The obstacles are compounded for RCTs of high-risk medical devices by extra costs related to the interventional procedure that is needed to implant the device, challenges with willingness to randomize patients throughout a trial, and difficulties in ensuring proper blinding even with sham procedures. One strategy that may help is to promote the wider use of simpler and more streamlined RCTs using data that are collected routinely during healthcare delivery. Recent large simple RCTs have successfully compared the performance of drugs and of high-risk medical devices, against alternative treatments; they enrolled many patients in a short time, limited costs, and improved efficiency, while also achieving major impact. From a task conducted within the CORE-MD project, we report from our combined experience of designing and conducting large pharmaceutical trials during the COVID-19 pandemic, and of planning and coordinating large registry-based RCTs of cardiovascular devices. We summarize the essential principles and utility of large simple RCTs, likely applicable to all interventions but especially in order to promote their wider adoption to evaluate new medical devices.

Following the publication of the original article [1], we were notified that the name of the 10 ^th author was incorrectly tagged in the article’s XML. <GivenName>Perla</GivenName> <GivenName>J.</GivenName> <GivenName>Marang-van</GivenName> <Particle>de</Particle> <FamilyName>Mheen</FamilyName> <GivenName>Perla</GivenName> <GivenName>J.</GivenName> <FamilyName>Marang-van de Mheen</FamilyName> The original article has now been corrected.

Before a high-risk medical device is approved for implantation into patients, there should be evidence not only of its performance and safety with a favourable benefit-risk ratio, but also of its clinical efficacy. Regulatory guidance on study methodologies is lacking, however, so the European Commission funded the CORE–MD project (Coordinating Research and Evidence for Medical Devices) to advise regulators on appropriate designs for clinical trials of high-risk devices. The CORE–MD consortium recommends that evaluation should be planned in four stages. Randomised controlled trials should be performed more often, against active comparators reflecting the best available treatment, or using sham interventions with ethical safeguards. Large trials can be managed efficiently using an electronic database or registry. Non-randomised clinical studies can apply objective performance criteria or other validated patient-relevant outcome measures, with adjustments to minimise bias. Full transparency of results from clinical investigations is essential. Proportionate regulation of breakthrough or orphan devices for independently-defined serious unmet needs may involve approval with less evidence, but on condition of subsequent confirmatory studies. These CORE–MD consensus proposals have been submitted to European Union medical device regulators, to be considered as a basis for more transparent and predictable requirements for clinical evidence. Funding: The CORE–MD project was funded as a Coordination and Support action from the European Union Horizon 2020 research and innovation programme, under grant agreement 965246.