They say you need to understand the problem before you can find a solution. ClinicalTrials.gov, a registry and results database, is a valuable resource for understanding the problem of insufficient clinical trial accrual. The web site is maintained by the National Library of Medicine (NLM) at the National Institutes of Health (NIH) and contains 160,091 study records on trials sponsored by NIH, other Federal agencies, nonprofit organizations and private industry. The database contains information on study participants and a summary of study outcomes. In addition to being a valuable resource for patients and clinicians to identify trials for possible participation, it is also a valuable tool for better understanding the problem of early termination of trials.
That's exactly what a group of cancer investigators at Mt. Sinai in New York did. Spurred by the Institute of Medicine's 2010 estimate that '40% of trials initiated by the National Cancer Institute's (NCI) Cooperative Groups never finish', the investigators, recognizing that only a portion of cancer clinical trials are conducted by the NCI's cooperative group system, wanted to look at the bigger picture. They analyzed 7,776 adult Phase II and III cancer trials registered on ClinicalTrials.gov between 2005 and 2011 to identify those trials that terminated prematurely and evaluate the reason for premature closure. Many would expect that studies fail to complete due to lack of efficacy or excess toxicity. However, poor accrual was the most common cause of trials failing to complete, accounting for almost 40% of those trials. Researchers found that trials conducted at a single location, trials with industry sponsors, and trials with study locations only inside the U.S. were more likely to fail. You can read the abstract here.
The results are likely not surprising to members of the clinical trial community who are visiting AccrualNet due to concerns about accrual. The good news is that the data available in ClinicalTrials.gov is a good source of information for developing a clear understanding of the problem. And the other piece of good news is that AccrualNet contains the literature, resources, and connection to colleagues to help meet the accrual challenges.