Current Landscape of Investigator-Initiated Decentralized Clinical Trials in Japan: A Nationwide Survey.

BACKGROUND: Decentralized clinical trials are becoming more widespread, driven by advances in digital technologies. However, little is known about the use of these trials in Japan. METHODS: We carried out a nationwide survey targeting 221 major clinical research institutions in Japan. Respondents were asked to report details of investigator-initiated decentralized clinical trials for which their institution was the lead facility for fiscal years 2021-2025. RESULTS: Overall, 82 institutions responded (37.1% response rate), including all 54 Clinical Research Core Hospitals and National University Hospitals (100% response rate), which are the institutions most likely to conduct investigator-initiated clinical research. Eighteen institutions (22.0%) reported conducting a total of 36 decentralized clinical trials, mostly at Clinical Research Core Hospitals or National University Hospitals. Twenty-one trials (58.3%) were classified as interventional studies under the Ethical Guidelines. Annual initiations increased from four in fiscal year 2021 to 15 in fiscal year 2024, and seven were reported for the incomplete fiscal year 2025. The most frequently used decentralized elements were electronic informed consent (eConsent) (14 trials, 38.9%) and online medical consultations (12 trials, 33.3%). Twenty-seven trials (75.0%) incorporated only one or two decentralized elements. Oncology was the most common disease area, although the trials spanned a wide range of therapeutic areas. CONCLUSIONS: The use of decentralized clinical trials is gradually increasing in Japan. These trials often use hybrid approaches incorporating a few decentralized elements, such as eConsent and online medical consultations. This pattern may reflect an approach adapted to Japan's unique regulatory, healthcare, and geographical circumstances.