Clinical trials initiated through cooperative groups and the time between first patient enrollment and trial activation are associated with slow patient recruitment. In a study published in Clinical Cancer Research, investigators identified characteristics and barriers to patient enrollment.1

“Clinical trials are the gold standard for evaluating treatments and for new drug approval; however, conducting a clinical trial is a very costly process, so it is important to ensure that the effort is successful,” explained J. Jack Lee, PhD, DDS, associate vice provost of quantitative research, professor of biostatistics at the University of Texas MD Anderson Cancer Center, and lead author.

The study analyzed data from 4269 clinical trials at the center between January 1981 and March 2011. A total of 755 trials with fewer than 2 participants per year were categorized as slow-accruing trials. Phase 3 and phase 2-3 trials accrued patients more slowly than phase 1 and phase 2 trials. Clinical trials initiated through cooperative groups were greater than 4 times more likely to slowly recruit patients than industry-sponsored trials, likely due to limited funding and fewer investigator incentives including peer-reviewed authorship. Lastly, trials that took more than 70 days between activation and first patient enrollment were 6 times more likely to slowly enroll patients. Delays to patient enrollment may be caused by the nature of the study, the complexity of the trial, the existence of multiple trials for the same patient groups, investigator enthusiasm, and trial resources.

Continue Reading

“Despite the best intent and effort, 9% of the trials in our study had zero accrual. These are the trials that we should not even develop to begin with,” said Lee. “Doctors and hospitals need to carefully vet the feasibility of a successful study accrual before opening a trial and be more mindful of investing in the areas of highest potential impact in order to maximize the utilization of available resources.”


1. Tang C, Sherman SI, Price M, et al. Clinical trial characteristics and barriers to participant accrual: The MD Anderson Cancer Center Experience over 30 years, a historical foundation for trial improvement. Clin Cancer Res. 2017 Mar 8. doi: 10.1158/1078-0432.CCR-16-2439 [Epub ahead of print]