Treatment of overactive bladder in the older patient: pooled analysis of three phase III studies of darifenacin, an M3 selective receptor antagonist

AIM: To evaluate the efficacy, tolerability and safety of darifenacin, an M(3) selective receptor antagonist, in the subgroup of older patients from a pooled analysis of three phase III, multicentre, randomized, double-blind clinical trials in patients with overactive bladder (OAB). PATIENTS AND METHODS: 317 patients aged > or =65 years with OAB symptoms (urge incontinence, urgency and frequency) received up to 12 weeks' oral treatment with darifenacin 7.5 mg or 15 mg once daily or matching placebo. Efficacy was evaluated from daily electronic diary records. Safety endpoints included withdrawal rates and treatment-related adverse events. RESULTS: Darifenacin treatment of patients aged > or =65 years was associated with a dose-related, significant improvement of all the major symptoms of OAB. At week 12, the median reduction in incontinence episodes/week was greater with darifenacin 7.5 mg or 15 mg than in the corresponding placebo arms (66.7% vs. 34.8% and 75.9% vs. 44.8%, respectively, both p < 0.001). Both doses were also significantly superior to placebo in improving micturition frequency (both p < 0.001), bladder capacity (volume voided) (darifenacin 7.5 mg, p = 0.018, darifenacin 15 mg, p < 0.001), and the frequency of urgency episodes (both p < 0.001). Darifenacin was well tolerated. The most common treatment-related adverse events were dry mouth (7.5 mg, 20.6%; 15 mg, 30.9%; placebo, 4.5%) and constipation (7.5 mg, 18.6%; 15 mg, 23.6%; placebo, 6.4%), typically mild or moderate. Use of constipation remedies (laxatives, stool softeners or fibre supplements) was low and similar between groups (7.5 mg, 10.3%; 15 mg, 16.4%; placebo, 10.0%). There were few withdrawals due to treatment-related adverse events (7.5 mg, 1.0%; 15 mg, 9.1%; placebo, 2.7%), and no nervous system or cardiovascular safety concerns. CONCLUSIONS: The results demonstrate excellent efficacy, tolerability and safety with darifenacin 7.5 mg and 15 mg once-daily treatment for OAB in older patients.