Time to onset of improvement in symptoms of overactive bladder using antimuscarinic treatment

OBJECTIVE: To evaluate the time to onset of statistically significant and clinically meaningful effects of trospium chloride in patients with an overactive bladder (OAB). PATIENTS AND METHODS: Data from a recent Phase III clinical study of trospium chloride were obtained, in which 658 patients with OAB were randomized (1 : 1) to placebo or trospium chloride 20 mg twice daily for 12 weeks. Original study safety endpoints consisting of adverse events, vital signs, electrocardiograms, and laboratory changes were collected, while original efficacy endpoints included number of toilet voids/day, urgency severity per toilet void, urge urinary incontinence (UUI), and volume voided per toilet void at weeks 1, 4, and 12. Results were also analysed using the OAB Symptom Composite Score (OAB-SCS). The efficacy analysis focused on changes from baseline in these endpoints from 1 to 7 days of treatment to establish the earliest point at which there was statistical significance or clinical efficacy. RESULTS: There were statistically significant improvements in efficacy over placebo in endpoints (toilet voids, urgency severity/void, UUI episodes, OAB-SCS) within a few days of treatment, with improvements in symptoms continuing to 7 days of treatment. There were clinically meaningful improvements in most endpoints by the end of the first week. CONCLUSIONS: The time to onset of the clinical effect should be studied more extensively to identify when patients might expect a clinically meaningful improvement in their OAB-related symptoms.