Efficacy and Safety of a Fixed-Dose Combination Therapy of Tamsulosin and Tadalafil for Patients With Lower Urinary Tract Symptoms and Erectile Dysfunction: Results of a Randomized, Double-Blinded, Active-Controlled Trial

Abstract

Background: Phosphodiesterase type 5 inhibitors and alpha-adrenergic blocking agents (alpha-blockers) are widely used for the treatment of erectile dysfunction (ED) and lower urinary tract symptoms (LUTS) associated with benign prostatic hyperplasia (BPH). Aims: To assess the efficacy and safety of fixed-dose combinations (FDCs) of tamsulosin and tadalafil compared with tadalafil monotherapy in patients with comorbid BPH-associated LUTS and ED. Methods: A randomized, double-blinded, active-controlled trial was conducted of 510 men with BPH-associated LUTS and ED. Patients were treated with FDCs of tamsulosin 0.4 mg plus tadalafil 5 mg (FDC 0.4/5 mg), tamsulosin 0.2 mg plus tadalafil 5 mg (FDC 0.2/5 mg), or tadalafil 5 mg for a 12-week treatment period. For a subsequent 12-week extension period, the patients were administered FDC 0.4/5 mg. Outcomes: The primary outcomes were changes from baseline in total International Prostate Symptom Score (IPSS) and International Index of Erectile Function erectile function domain (IIEF-EF) score at week 12 to prove superiority and non-inferiority of FDCs compared with tadalafil 5 mg. The safety assessments were adverse reactions, laboratory test results, and vital signs at week 24. Results: The mean changes in total IPSS and IIEF-EF scores were -9.46 and 9.17 for FDC 0.4/5 mg and -8.14 and 9.49 for tadalafil 5 mg, respectively, which indicated superiority in LUTS improvement (P =.0320) and non-inferiority in ED treatment with FDC 0.4/5 mg compared with tadalafil 5 mg. However, the results from FDC 0.2/5 mg failed to demonstrate superiority in LUTS improvement. No clinically significant adverse events regarding the investigational products were observed during the 24-week period. Clinical Implications: The FDC 0.4/5 mg is the first combined formulation of an alpha-blocker and a phosphodiesterase type 5 inhibitor that offers benefits in patient compliance and as add-on therapy in patients with comorbid BPH-associated LUTS and ED. Strengths and Limitations: The study clearly demonstrated the advantage of FDC 0.4/5 mg. The main advantage of FDC 0.4/5 mg was the enhanced efficacy on BPH-associated LUTS comorbidity with ED, the lower incidence of side effects, and the simplification and convenience of therapy, which led to better overall patient compliance. However, the lack of a tamsulosin monotherapy control group was a limitation of this study. Conclusion: The FDC 0.4/5 mg therapy was safe, well tolerated, and efficacious, indicating that combination therapy could provide clinical benefits for patients with BPH-associated LUTS complaints and ameliorate the comorbidity of ED. Copyright (C) 2017, International Society for Sexual Medicine. Published by Elsevier Inc. All rights reserved.