Potential Primary Endpoint for Exploratory Clinical Trial in Patients with Overactive Bladder: A Systematic Literature Review

ObjectivesTo identify a potential primary endpoint in an early-phase exploratory trial among key overactive bladder (OAB) symptoms. MethodsPlacebo-controlled double-blinding trials in patients with OAB were extracted for systematic literature review. The correlation between key OAB symptoms recorded in bladder diaries and coefficient of variation (CV) in each study were assessed. ResultsForty-one controlled trials were extracted for the present review. Mean number of urgency episodes in 24 h was substantially associated with mean number of urgency incontinence episodes in 24 h, mean volume voided per micturition, and mean number of micturitions in 24 h (Spearman's r = 0.725, -0.661, and 0.657, respectively). Mean number of micturitions in 24 h was also substantially associated with mean volume voided per micturition (Spearman's r = -0.674). Mean number of incontinence episodes in 24 h was substantially associated with mean number of urgency incontinence episodes in 24 h and mean volume voided per micturition (Spearman's r = 0.840 and -0.628, respectively). The median CV of mean volume voided per micturition in each trial was the smallest among all endpoints. ConclusionsOur findings suggest that volume voided per micturition is a useful symptom for evaluating OAB candidate compounds in a small sample size and represents an effective primary endpoint, especially in exploratory clinical trials.