Cancer trials with lengthy development time linked with failure to reach accrual goals

NEW YORK (Reuters Health) - A substantial number of U.S. cancer treatment trials do not achieve minimum patient accrual goals, and the longer it takes to develop the clinical trial, the more difficult it is to accrue enough patients to achieve statistically significant results, research shows.

These observations, reported at the American Society of Clinical Oncology meeting in Orlando this week, stem from a review of all 553 therapeutic, non-pediatric phase I, II and III clinical trials sponsored by the National Cancer Institute's (NCI) Cancer Therapy Evaluation Program (CTEP) between 2000 and 2007.

Overall, 40 percent of the trials (n = 221) did not achieve their minimum accrual goals as defined by the investigators when the study opened, Dr. Steven K. Cheng, from Oregon Health and Science University, who spearheaded the research, reported at ASCO.

Looking specifically at phase III trials, "more than 3 out of 5 did not meet their minimum projected accrual," Dr. Cheng said. "This is important because phase III trials are the most time consuming and the priciest of all phases to conduct."

Trial development time -- defined as the time from initial CTEP submission of the concept to the time the trial began enrolling patients -- emerged as an important predictor of patient accrual success.

The median trial development time was 15 months. Studies that developed more quickly than the median -- within 9 to 12 months -- were significantly more likely to achieve their minimum patient accrual goal (odds ratio, 1.94), with 77 percent achieving their goal, Dr. Cheng reported.

Conversely, studies that took the longest time to develop -- more than 27 months - were significantly less likely to achieve minimum patient accrual goals, with just 22 percent achieving their goal (odds ratio, 0.14).

Overall, 8723 patients who agreed to participate in the studies (17% of accruals) were enrolled in trials that did not achieve their minimum projected accrual goal at the study closure.

Dr. Cheng noted that research is currently underway to identify ways to shorten cancer clinical trial development times, and if those changes improve accrual rates.

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