1. ¹Department of Urology, Yonsei University Health System, Seoul, South Korea
2. ²Department of Urology, UT Southwestern Medical Center, Dallas, TX, USA
3. ³Welborn Clinic, Evansville, IN, USA
4. ⁴Clinical Development, GlaxoSmithKline, Research Triangle Park, NC, USA
5. ⁵Department of Biostatistics, GlaxoSmithKline, Research Triangle Park, NC, USA
6. ⁶Department of Urology, Universita Vita Salute San Raffaele, Milan, Italy

Correspondence: Dr B-H Chung, Department of Urology, Yonsei University Health System, Yongdong Severance Hospital, Yongdong P.O. Box 1217, Seoul, South Korea. E-mail: chung646@yuhs.ac

Received 8 July 2008; Revised 27 August 2008; Accepted 27 August 2008; Published online 23 September 2008.

Abstract

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 0.5 mg dutasteride once daily, 0.4 mg 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.