Is mirabegron equally as effective when used as first- or second-line therapy in women with overactive bladder?

Introduction and hypothesis: No previous studies have investigated the efficacy of mirabegron 50 mg as the first-line therapy in OAB patients. Hence, the primary objective of this study was to evaluate the efficacy of mirabegron in treatment-naive patients in comparison with those who had discontinued antimuscarinic therapy because of insufficient efficacy. Methods: All consecutive women who had pure OAB symptoms (including urgency with or without urgency incontinence and frequency) for at least 3 months were considered for this study. Women were divided into two groups: women without any previous pharmacological treatment for OAB (group 1) and women with a previous history of failed antimuscarinics therapy (group 2). Results: At 3-month follow-up, the objective results on the basis of the frequency–volume chart showed a significant improvement in both groups. Furthermore, a significant reduction in the Overactive Bladder Questionnaire Short Form (OABq-SF) score and in the Indevus Urgency Severity Scale (IUSS) questionnaire were reported in both groups. However, the improvement in objective and subjective outcomes was superior in group 1 to that in group 2. Conclusions: Mirabegron is efficacious in improving OAB symptoms in both naïve patients and those who discontinued primary antimuscarinic therapy; however, its efficacy is superior when prescribed as first-line therapy.