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

Importance: ClinicalTrials.gov is a valuable resource that can be used to trace the state and nature of trials. Since its launch in 2000, more than 345 000 trials have been registered. Little is known about the characteristics and trends in clinical trials over time and how they differ by sponsor type. Objective: To assess trends in clinical trials registered in ClinicalTrials.gov over time and by sponsor type. Design, Setting, and Participants: This cross-sectional study included clinical trials (interventional studies) registered in ClinicalTrials.gov from January 1, 2000, through December 31, 2019. The trials were grouped by lead sponsor: National Institutes of Health (NIH) and other US government agencies, industry, and other sources (foundations, universities, hospitals, clinics, and others). A static version of the Clinical Trials Transformation Initiative Aggregate Analysis of ClinicalTrials.gov database was downloaded on January 1, 2020, for analysis. Main Outcomes and Measures: ClinicalTrials.gov registration fields, including overall status, phase, intervention, number of sites, use of masking and randomization, sample size, and time to study completion by start year and lead sponsor (organization that provided funding or support for a clinical study). Results: A total of 245 999 clinical trials (interventional studies) were started between 2000 and 2019, of which 135 144 (54.9%) were completed. Among completed trials, 5113 (3.8%) were sponsored by the NIH or a US government agency, 48 668 (36.0%) by industry, and 81 363 (60.2%) by other sources. Most trials were single center (61.3%), randomized (65.6%), and phase 1 to 2 (35.5%) or did not have a US Food and Drug Administration-defined phase (38.4%), with fewer drug trials being conducted over time. Sample sizes were small (median, 60; interquartile range [IQR], 30-160) and diminished over time. Trial median completion times varied by lead sponsor: 3.4 years (IQR, 1.9-5.0 years) for NIH- and US government-sponsored trials, 1.2 years (IQR, 0.5-2.4 years) for industry trials, and 2.1 years (IQR, 1.1-3.7) for trials sponsored by other sources. Conclusions and Relevance: The findings suggest that the composition and design of trials changed from 2000 to 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.

Gender indexing in publications of clinical trials: 1991-2008.

BACKGROUND: In 1993 Congress passed the NIH Revitalization Act, which instructed the Director of the NIH to ensure that phase III clinical trials are 'designed and carried out in a manner sufficient to provide for a valid analysis of whether the variables being studied in the trial affect females or members of minority groups, as the case may be, differently than other subjects in the trial.' PURPOSE: The purpose of this article is to track the PubMed indexing of gender in clinical trial publications since 1991 with a view toward assessing the impact of the legislation on the number of gender specific trials. METHODS: We searched PubMed for full-length publications from years 1991 to 2008 of research on humans indexed as publication type 'clinical trial', 'randomized clinical trial' and multicenter randomized trial ('multicenter study' AND 'randomized clinical trial'), and counted the number of trials indexed as male-only, female-only, male and female, and gender unknown in PubMed. RESULTS: The majority of trial publications were indexed in PubMed as including both genders. The proportion of publications indexed as including both genders has increased while the number of publications not indexed with respect to gender and the number of publications indexed as male-only have decreased. In 2005, approximately 13% of NIH expenditures were for female specific or related research compared to 6% for male specific or related research. LIMITATIONS: The proportion of clinical trial publications that were indexed in PubMed as including females began to increase before the legislation so it is difficult to conclude that changes in the number of female-only or male-only trials are due to the legislation. PubMed listings do not include gender enrollment, so female and male enrollment totals could not be compared. CONCLUSIONS: The NIH policy should be rewritten to be made gender neutral to bring it in line with the principle of justice as embodied in the Belmont Report.