Better access to information about clinical trials.

Access to information about clinical trials is important to researchers, health care professionals, and patients. Many have argued for the establishment of clinical trials registries, citing their substantial benefits. Although some registries do exist, it has been difficult to create comprehensive, easily accessible systems. This paper briefly reviews existing registries, discusses the challenges in building registries, and reviews some of their benefits. The paper concludes with a description of a new, extensive Web-based registry called ClinicalTrials.gov (http://clinicaltrials. gov/), which was developed at the National Institutes of Health (NIH) by the National Library of Medicine as a result of recent legislation calling for a comprehensive, publicly accessible registry of clinical trials. The first version of the system became available in late February 2000 and contains information about approximately 5000 trials. The first release contains primarily NIH-sponsored trials, and new trials are regularly added to the system. Subsequent versions will contain information about trials sponsored by other federal agencies and by the private sector. The system was developed in accordance with basic informatics principles, including adherence to standards, usability considerations, and iterative testing and evaluation.