Nearly one in four publicly sponsored cancer clinical trials fail to enroll enough participants to draw valid conclusions about treatments or techniques, and there are specific reasons, according to a study by researchers at Fred Hutchinson Cancer Institute and the University of Washington.
Such trials represent a waste of scarce human and economic resources and contribute little to medical knowledge, the authors wrote in the article, now online ahead of print in the Journal of the National Cancer Institute (doi:10.1093/jnci/djv324).
A news release notes that although many studies have investigated the perceived barriers to accrual from the patient or provider perspective, this is one of very few that have taken a "trial-level" view and asked why certain trials are able to accrue patients faster than expected while others fail to attract even a fraction of the intended number of participants.
The research team, led by Caroline S. Bennette, MPH, PhD, of the Pharmaceutical Outcomes Research and Policy Program of the University of Washington, analyzed information on 787 Phase II/III clinical trials sponsored by the National Clinical Trials Network (NCTN) that were launched between 2000 and 2011. After excluding trials that closed because of toxicity or interim results, the researchers found that 145 of the trials (18%) closed with low accrual or were accruing at less than 50 percent of the target accrual three or more years after opening.
The authors identified potential risk factors from the literature and interviews with clinical trial experts and found multiple trial-level factors that were associated with poor accrual to NCTN trials, such as:
* Increased competition for patients from currently ongoing trials;
* Planning to enroll a higher proportion of the available patient population; and
* Not evaluating a new investigational agent or targeted therapy.
The researchers then developed a multivariable prediction model of low accrual using 12 trial-level risk factors, which they reported had good agreement between predicted and observed risks of low accrual in a preliminary validation using 46 trials opened between 2012 and 2013.
Systematically considering the overall influence of these factors could aid in the design and prioritization of future clinical trials, the authors concluded.
"The research provides a response to the recent directive from the Institute of Medicine to improve selection, support, and completion of publicly funded cancer clinical trials."