Efficacy and safety of dutasteride, tamsulosin and their combination in a subpopulation of the CombAT study: 2-year results in Asian men with moderate-to-severe BPH

Although ethnicity-based differences in prostate size and physiology have been reported, results of benign prostatic hyperplasia (BPH) treatment trials in predominantly Caucasian patients are assumed to be applicable to non-Caucasian populations. This post hoc analysis investigated whether an Asian subpopulation of men with moderate-to-severe BPH in the CombAT study achieves treatment responses in line with those of the overall study population. In this double-blind, randomized, parallel-group trial, 325 Asian men were assigned to treatment with 0.5mg dutasteride once daily, 0.4mg tamsulosin once daily or the combination. Decrease in international prostate symptom score (IPSS) at month 24 from baseline (the primary endpoint) was significantly greater with combination treatment compared with tamsulosin (P<0.05), and numerically, but not statistically significantly, greater compared with dutasteride. Mean IPSS was reduced from baseline by 7.5 (±0.84) in the combination group, by 6.3 (±0.86) in the dutasteride group and by 4.5 (±0.78) in the tamsulosin group, resulting in respective mean IPSS at months 24 of 11.4 (±0.60), 12.7 (±0.70) and 14.3 (±0.74). The adverse event profile was similar to that observed in the overall CombAT population, and drug-related adverse events were more common with combination therapy (26%) than with tamsulosin (15%) or dutasteride (9%). No unexpected adverse events emerged. In conclusion, in Asian men with moderate-to-severe lower urinary tract symptoms and an enlarged prostate, combination therapy achieved significantly greater improvements from baseline BPH symptoms, flow rate, quality of life, reduced prostate volume and improved treatment satisfaction compared with tamsulosin monotherapy.