LAUSR

Background Increasing costs and complexity in clinical trials requires recruitment of more narrowly defined patient populations. However, recruitment for clinical trials remains a considerable challenge. Aim Our overall aim was to quantify recruitment performance in industry-sponsored phase III clinical trials conducted globally during 2008–2019 with primary aim to examine development of overall clinical trial measures (number of trials completed, number of participants enrolled, trial duration in months) and key recruitment metrics (recruitment rate, number of sites, number of patients enrolled per site). Methods The publicly available AACT database containing data on all trials registered at ClinicalTrials.gov since 2008 was used. The analysis was completed during three time periods from 2008–2019 of 4 years each. Results and conclusion Recruitment duration for industry-sponsored phase III clinical trials have increased significantly during the last 12 years from an average recruitment period of 13 months (IQR 7–23) in 2008–2011 to 18 months (IQR 11–28) in 2016–2019 (p = 0.0068). Further, phase III clinical trials have increased the number of registered sites per clinical trial by more than 30% during the last 12 years from a median number 43 sites (IQR 17–84) in 2012–2015 to 64 sites (IQR 30–118) in 2016–2019 (p = 0.025), and concurrently, the number of participants enrolled in clinical research has decreased significantly from 2012–2015 and 2016–2019 (p = 0.046). We believe that these findings indicate that recruitment for phase III clinical trials is less effective today compared to 12 years ago.