LAUSR

439 Background: Poor accrual to clinical trials is the most cited barrier to efficient trial completion, yet information regarding accrual adequacy is limited. Comparisons of planned (or anticipated) accrual to actual accrual have previously been limited by siloed information. Even ClinicalTrials.gov presents only one type of accrual (actual OR anticipated) for each trial. We developed a novel approach to extract both anticipated and actual trial accrual. We apply these previously unavailable data to describe accrual adequacy and identify predictors of poor accrual. Methods: Records for all GU cancer clinical trials started since 2005 were extracted from ClinicalTrials.gov. We employed a custom Python web scraper to extract anticipated and actual accrual information and trial characteristics from the ClinicalTrials.gov archives. Logistic regression was used to identify predictors of failing to meet 50% or 85% of anticipated accrual. Results: A total of 3,976 completed or terminated genitourinary cancer trials were extracted, of which 1,322 unique trials had complete records. Only 42% of trials met their anticipated accrual goals, and 30% enrolled fewer than half of their anticipated patients (Table). Of trials reported as completed, only 54% reached their accrual goals; 17% failed to reach 50% of anticipated accrual. On logistic regression, prostate (OR 0.64, 95% CI 0.45-0.91) and testicular (OR 0.44, 95% CI 0.18-0.96) trials, as well as trials with sites within and outside the USA (OR 0.55, 95% CI 0.35-0.86) were more likely to accrue > 50% of anticipated patients. Conclusions: Genitourinary cancer clinical trials frequently fail to meet anticipated accrual goals. Whether this represents overly ambitious goals or modified endpoints after a trial opens remains uncertain. These data should be transparent and applied to the interpretation of results. Future work in this regard should be used to aid in planning future trials. [Table: see text]