Analyses of how clinical trials accrue patients are needed at the institutional level, according to an article published in Clinical Cancer Research.1

Trials with slow participant accrual are at risk of becoming redundant before completion, wasting resources, and closing prematurely; there is therefore a need to identify and mitigate factors linked to slow accrual. For this analysis, researchers reviewed clinical trials conducted at MD Anderson Cancer Center between 1981 and 2011 to identify these factors and promote initiatives to prevent slow accrual.

Of 4269 phase 1-3 trials reviewed, median participants enrolment was 16, with an average of 8.7 participants enrolled per year (trials with maximum projected patients of fewer than 10 were not evaluated). Nearly a fifth of evaluated trials were classified as having slow accrual, defined as enrolling fewer than 2 participants per year; nearly 10% of trials enrolled 0 participants overall.

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Trial characteristics associated with slow accrual included being a member of a national cooperative group, delay from activation to first enrolment, and having a higher maximum target accrual. Phase 1 trials accrued participants more quickly than did phase 2 or 3 trials.

If a clinical trial resulted in a publication, trials classified as “non-slow-accruing” had an almost 5-fold higher publishing rate than slow-accruing trials. The authors claimed that this suggests that the possibility of academic success derived from a particular trial for a principle investigator leads to a higher accrual rate.

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Tactics introduced to mitigate slow accrual at MD Anderson included flagging slow-accruing trials and requiring investigators to improve accrual rates, providing extra funding for local investigators involved in national cooperative group trials, and creating a program—the High-Impact Clinical Research Support Program (HI-CRSP)—which provides extra funding for successful applications from underfunded studies.


  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]