Introduction: East Asia, including China, Japan, South Korea, and Taiwan, has become a major hub for clinical trials. However, comprehensive comparisons between ClinicalTrials.gov and local registries remain limited. This study analyzes registered clinical trial trends in East Asia over the past decade (2014-2023) and compares them to trends in the United States. Methods: We extracted clinical trial data through the International Clinical Trials Registry Platform (ICTRP), including data from local registries and ClinicalTrials.gov for China, Japan, South Korea, Taiwan, and the United States. We analyzed overall clinical trial trends and filtered randomized controlled trials (RCTs), categorizing them by location, target size, and disease category. Results: China experienced rapid growth in clinical trials, surpassing both Japan and the United States in total trials and RCTs. By 2023, China led with 16,612 total trials (7,798 RCTs), while the United States registered 9,100 (4,619 RCTs). Except for China, all other countries showed some decline in recent years. Neoplastic diseases and cardiovascular and metabolic diseases were prominent in both regions, but the U.S. showed growing focus on mental health. China's RCTs were predominantly domestic, while the U.S. maintained a higher proportion of international trials. Japan, South Korea, and Taiwan showed moderate growth, with fewer international trials than the United States. We recorded some inconsistencies and missing information across existing registries. Conclusion: The study highlights the increasing prominence of East Asia, particularly China, in registered clinical trials, though with a primarily domestic focus. Improvements in existing trial registries covering East Asia are desirable.

The authors have declared no competing interest.

The work of John Ioannidis is supported by an unrestricted gift from Sue and Bob O'Donnell to Stanford University.

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The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

The study was not subject to institutional review board approval because it exclusively utilized open-source trial information from ClinicalTrials.gov and local registries via the ICTRP and TPIDB, without including any individual participant data.

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The data supporting this study are available in an open-access repository at https://osf.io/f58y7/.

https://osf.io/f58y7/