Additional low-dose antimuscarinics can improve overactive bladder symptoms in patients with suboptimal response to beta 3 agonist monotherapy

Purpose: We aimed to assess the patient-reported outcome (PRO) and efficacy of add-on low-dose antimuscarinic therapy in overactive bladder (OAB) patients with suboptimal response to 4-week treatment with beta 3 agonist monotherapy (mirabegron, 50 mg). Materials and Methods: We enrolled OAB patients with 4-week mirabegron (50 mg) treatment if the patients’ symptoms improved, but not to a satisfactory extent (patient perception of bladder condition [PPBC] ≥4). Enrolled patients had 8-week lowdose antimuscarinics add-on therapy (propiverine HCl, 10 mg). Patients recorded 3-day voiding diary at screening, enrollment (after 4 weeks of mirabegron monotherapy) and after 8 weeks of add-on therapy. We assessed the change of PRO (PPBC) as a primary end point and the efficacy of add-on therapy (change of frequency, urgency, urinary urgency incontinence [UUI] based on voiding diary) as a secondary end point. Results: Thirty patients (mean age, 62.3±12.8 years; mean symptom duration, 16.0±12.3 months) were finally enrolled in the study. The mean PPBC value was 4.3±0.4 after mirabegron monotherapy, and decreased to 3.2±1.0 after 8-week add-on therapy. The mean urinary frequency decreased from 10.1±3.1 to 8.8±3, the mean number of urgency episodes decreased from 3.6±1.6 to 1.8±1.2 and the number of urgency incontinence episodes decreased from 0.7±1.0 to 0.2±0.5 after add-on therapy. No patients had event of acute urinary retention and three patients complained of mild dry mouth after add-on therapy. Conclusions: Add-on therapy of low-dose antimuscarinics exhibits good efficacy and safety in patients with suboptimal response after 4-week of mirabegron (50 mg) monotherapy