Greater complexity and global reach
Since 2000, the number of developmental drug compounds has increased as has the complexity of clinical trials. Approximately 2040 compounds were under development in 2001, and this number increased nearly 50% in 2010 to 3050 compounds, according to a recent report by the Pharmaceutical Research and Manufacturers of America (1). Between 2000–2003 and 2004–2007, the median number of procedures per clinical trial increased by 49% while the total work burden per protocol grew by 54% (1, 2). As complexity increases, so do eligibility criteria for volunteers, which lead to lower volunteer recruitment and retention rates. The average number of eligibility criteria for volunteers has increased by 58%, and volunteer enrollment and retention rates have declined by 21% and 30%, respectively (1, 2).
Western Europe accounted for most foreign clinical-trial subjects and sites (approximately 60%). Central and South America had the highest average number of subjects per site, accounted for 26% of all subjects enrolled at foreign trial sites, and 7% of foreign sites. According to estimates cited by the HHS report, between 40% and 65% of clinical trials investigating FDA-regulated products are conducted outside of the US. A recent analysis of http://ClinicalTrials.gov/, a National Institutes of Health registry and results database of federally and privately supported clinical trials, examined recruitment in industry-sponsored Phase III clinical trials and found that as of November 2007, one-third of the clinical trials of the 20 largest US-based pharmaceutical companies were conducted at foreign sites (3, 4).