Characterization of medical device randomized controlled trials with adaptive designs

Aim: Adaptive designs are frequently used in drug randomized controlled trials (RCTs). However, their use in medical device RCTs remains unclear. We aimed to characterize medical device RCTs with adaptive designs. Materials & methods: We searched for adaptive RCTs in the following databases: ClinicalTrials.gov, International Clinical Trials Registry Platform and the International Standard Randomised Controlled Trial Number registry. Adaptive design keywords and medical device corporation names were used as terms to search the trial records registered between 1 January 2000 and 18 October 2024 in the databases. The annual number and proportions of adaptive trials were analyzed, and characteristics such as design type, sponsor, therapeutic area, trial stage and regulatory status were summarized. Results: Overall, 105 adaptive RCTs were identified from ClinicalTrials.gov, accounting for 2.112 per 1000 trials in 49,721 medical device clinical trials registered in ClinicalTrials.gov during the period. The average annual number of adaptive RCTs per 1000 clinical trials was the highest (8.55 ± 11.65) during 2005-2010, reduced to 3.33 ± 2.35 during 2011-2016, and significantly decreased to 1.29 ± 0.85 during 2017-2024 (p = 0.011). The most common adaptive designs were group sequential design (GSD, 50.5%), sample size reassessment (SSR, 17.1%) and investigating both superiority and non-inferiority (10.5%). Most RCTs were sponsored by the private sector (62.9%), conducted in Europe/North America (95.2%), in the field of heart disease (46.7%) and post-market trials (76.2%). Compared with pre-market RCTs, post-market RCTs showed more diverse adaptive designs such as response-adaptive randomization and adaptive enrichment. Conclusion: The average annual proportions of adaptive medical device RCTs in ClinicalTrials.gov has reduced in the last 10 years. The most-used adaptive designs in medical device RCTs are GSD, SSR and investigating both superiority and non-inferiority.