Efficacy of Combination Treatment with Tadalafil and Mirabegron in Patients with Benign Prostatic Hyperplasia Who Presented with Persistent Storage Symptoms After Tadalafil Monotreatment: A Prospective, Multicenter, Open-Labeled Study

Background: The aim of this study is to evaluate the efficacy and safety of tadalafil, a phosphodiesterase type 5 inhibitor, plus mirabegron, a β3-adrenoreceptor agonist, in patients with benign prostatic hyperplasia who presented with persistent storage symptoms after tadalafil monotreatment. Methods: The registration of this study started in August 2016 and ended in July 2019. The inclusion criteria included patients aged ? 50 years who were diagnosed with benign prostatic hyperplasia and who presented with overactive bladder symptoms. Patients were treated with oral tadalafil 5 mg once daily for 4 weeks. Then, its efficacy was evaluated. Patients who responded to the treatment received oral tadalafil 5 mg once daily for 4 more weeks (monotreatment group). Meanwhile, those who did not respond received oral tadalafil 5 mg and mirabegron 50 mg, which is an add-on treatment, once daily for 4 more weeks (combination therapy group). Results: After 8 weeks, the monotreatment group (n = 19) and the combination group (n = 56) had significantly better total Overactive Bladder Symptom Score and International Prostate Symptom Score and International Prostate Symptom Score voiding and storage subscale scores. Moreover, the two groups experienced significant improvements in the total Overactive Bladder Questionnaire and Nocturia Quality of Life Questionnaire scores, and Nocturia Quality of Life Questionnaire Bother/Concern subscale score after 8 weeks. However, there were no cases of urinary retention or serious adverse events. Conclusion: Combination treatment with tadalafil and mirabegron is effective and safe for patients with benign prostatic hyperplasia who presented with persistent storage symptoms after tadalafil monotreatment. Hence, tadalafil plus mirabegron is a promising therapeutic option, and it can improve overactive bladder related-quality of life.