Assessment of Trends in the Design, Accrual, and Completion of Trials Registered in ClinicalTrials.gov by Sponsor Type, 2000-2019

Key Points Question What are the characteristics and trends of clinical trials registered in ClinicalTrials.gov over time, and how do they differ by sponsor type? Findings In this cross-sectional study of ClinicalTrials.gov registration data on 245 999 interventional studies started between 2000 and 2019 that were sponsored by the National Institutes of Health or other US government agencies, industry, or other sources (foundations, universities, hospitals, clinics, and others), most trials were small, single-site studies that did not have US Food and Drug Administration–defined phases and were sponsored by other sources. Median sample sizes and years to trial completion decreased over time. Meaning The findings suggest that the composition and design of trials changed between 2000 and 2019 and differed substantially by sponsor type; increased funding toward larger randomized clinical trials may be warranted to inform clinical decision-making and guide future research.