Tadalafil for the Treatment of Lower Urinary Tract Symptoms in Japanese Men with Benign Prostatic Hyperplasia: Results from a 12‐week Placebo‐controlled Dose‐finding Study with a 42‐week Open‐label Extension

Objectives: To examine the efficacy, safety, and dose response of tadalafil once daily in Japanese men with lower urinary tract symptoms suggestive of benign prostatic hyperplasia (BPH‐LUTS). Methods: Men ≥45 years with moderate‐to‐severe BPH‐LUTS were randomized to once‐daily placebo (N = 140), tadalafil 2.5 mg (N = 142), or tadalafil 5.0 mg (N = 140), in a 12‐week double‐blind phase, followed by a 42‐week, tadalafil 5.0 mg open‐label extension (OLE) phase (N = 394). The primary outcome was total International Prostate Symptom Score (IPSS) change from baseline to last available observation in the double‐blind phase. Results: The least squares (LS) mean difference between placebo and tadalafil in total IPSS change from baseline was ?0.7 (P = 0.201) and ?1.1 (P = 0.062) for tadalafil 2.5 and 5 mg, respectively (ANCOVA; a dose‐dependent improvement in placebo‐adjusted total IPSS for tadalafil 5 mg versus 2.5 mg of 57%). Repeated‐measures analyses identified a significant total IPSS change for tadalafil 5 mg (LS mean difference between placebo and tadalafil 5 mg: ?1.2; P = 0.035), but not tadalafil 2.5 mg, at week 12. Significant improvements for tadalafil 5 mg were demonstrated (ANCOVA) for IPSS obstructive subscore (P = 0.033) and IPSS quality of life index (P = 0.022). Numerical improvements in IPSS scores were maintained over the OLE phase. Tadalafil was well tolerated with no unexpected adverse events. Conclusion: Tadalafil (5.0 mg) had a favorable benefit‐to‐risk profile, supporting further investigation of tadalafil (5.0 mg) in Japanese men with BPH‐LUTS.