One in 5 Clinical Trials in Adult Cancer Not Completed

Zosia Chustecka

January 29, 2014

Around 20% of clinical trials that are started in adult cancer patients fail to complete for reasons other than efficacy or adverse effects of the intervention being tested. These trials are wasting money and leave unanswered questions of how best to care for patients, say researchers.

The finding was highlighted at a presscast ahead of the 2014 Genitourinary Cancers Symposium in San Francisco.

"Clinical trials are the cornerstone of progress in cancer care," said lead investigator Matthew Galsky, MD, associate professor of medicine at the Icahn School of Medicine at Mount Sinai in New York City. "Given their critical role, it's important that efficiency of the clinical trial enterprise be optimized, and it goes without saying that these trials that are initiated and then fail to complete....represent an extreme example of inefficiency in the system."

"Such trials contribute little knowledge, waste financial resources, and potentially divert patients from participating in other trials," he added.

"This issue of trials failing to complete has mainly flown under the radar," he commented. Some attention was drawn to it in a recent Institute of Medicine report, which found that about 40% of all trials funded by the National Cancer Institute Cooperative Groups failed to complete. However, this represents only a small proportion (perhaps around 15%) of the entire cancer clinical trial enterprise, he noted.

His team set out to investigate the issue on a broader scale, and they analyzed 7776 adult cancer phase 2 and 3 intervention clinical trials that had been registered in between 2005 and 2011. They found that 935 trials had been terminated prematurely (identified as "stopped early" in the registry).

The main reason for early termination was given as poor accrual (38.7%), followed by sponsor cancellation (10.6%), results at interim analysis (9.9%), toxicity/adverse events (8.2%), and lack of funding (5.6%).

Poor accrual is a real problem, Dr. Galsky commented, and has been highlighted in other studies. Not getting patients into a trial means that any answers to clinical questions are generated very slowly, and questions are not answered at all if the trial is stopped, he said. "We really need some novel approaches to improve patient accrual into cancer trials, which has been quite steady at around 3% to 5% of all the adult cancer population for decades," he added.

"This is a real frustration that all cancer researchers share," commented moderator Charles Ryan, MD, from the Helen Diller Family Comprehensive Cancer Center at the University of California, San Francisco. "I hope that this will start a broader discussion of how to improve efficiencies," he added.

One suggestion from Dr. Galsky is to review patient eligibility into clinical trials. "At the moment, the inclusion criteria are so strict that only the very fittest cancer patients are enrolled," he said.

Not Better and Not Worse

Dr. Galsky, who is also director of the genitourinary medical oncology program at the Tisch Cancer Institute, explained that his interest in this issue was piqued after several trials in a row in bladder cancer had failed to complete. One of the questions the team addressed in their analysis was whether trials in genitourinary cancers are more likely than other cancers to be terminated early, but there was no evidence for this. "The risk was not significantly different for kidney, bladder, or testis cancer compared to other cancer types, with the exception of prostate cancer," the researchers report.

They also found that trials with industry sponsorship were more likely to fail to complete, as were trials at single sites (compared with multiple sites) and trials that were conducted only within the United States (compared with trials with sites both inside and outside the United States).

Dr. Galsky and colleagues have disclosed no relevant financial relationships. Dr. Ryan reports receiving honoraria from Astellas Pharma, Janssen Biotech, Millennium, and Sanofi.

2014 Genitourinary Cancers Symposium (GUCS): Abstract 288. To be presented January 31, 2014.


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