1 in 5 US Clinical Trials Fails to Complete

February 2014, Vol 5, No 1

San Francisco, CA—The early termination of clinical trials is a tremendous waste of resources and can leave patients with cancer with no improved treatment options. For the first time, a comprehensive study of the clinical trial enterprise in the United States has shown that 20% of 7776 adult phase 2 and 3 clinical trials registered on ClinicalTrials.gov were terminated early. Furthermore, early terminations occurred across all cancer types, according to this retrospective study presented at the 2014 Genitourinary Cancers Symposium.

Factors associated with the likelihood of early termination included being conducted at a single site, industry sponsorship, and trials conducted exclusively within the United States.

The investigators were alerted to the problem after noticing that a series of bladder cancer trials failed to complete, “leaving little evidence to guide clinical decision-making in bladder cancer,” said lead investigator Matthew D. Galsky, MD, Director, Genitourinary Medical Oncology, Tisch Cancer Institute, Mount Sinai, New York.

A 2010 Institute of Medicine report showed that approximately 40% of all trials initiated by the National Cancer Institute (NCI) Clinical Trials Cooperative Group Program were not completed. NCI-sponsored trials account for only approximately 15% of all clinical trials in the United States. Dr Galsky and colleagues looked at the full scope of the problem of early termination within the larger clinical trial enterprise, which he said had not been done before.

“Clinical trials that fail to complete waste financial resources and human capital. The results of this study further highlight the wide-ranging impact of poor accrual to cancer clinical trials in the United States. The fact that a large proportion of clinical trials are not completed at all is a major barrier to progress in cancer care,” Dr Galsky stated.

Of 7776 phase 2 and 3 adult cancer clinical trials registered at Clinicaltrials.gov between 2005 and 2011, approximately 20% failed to complete. The most common reasons for early termination were:

  • Poor accrual, 38.7%
  • Toxicity/efficacy, approximately 20%
  • Logistics, approximately 20%
  • Other, including sponsor cancellation (10.6%) and lack of funding (5.6%).

Dr Galsky said that trials sponsored by industry and trials conducted at a single site in the United States were twice more likely to be terminated early than those conducted in multicenters; those conducted outside the United States were 33% less likely to fail than trials conducted in this country.

“These results suggest that approximately 48,000 cancer patients were enrolled in failed trials. Poor accrual was the most common reason. These failed trials impact all cancer types, waste resources, increase expenditures, and prevent us from getting answers about optimal treatment more quickly,” Dr Galsky stated.

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