Results of US Phase III Double-blind Comparative Studies of Silodosin (Brand name in Japan: Urief®)

Kissei Pharmaceutical Co., Ltd (President, C.E.O. Mutsuo Kanzawa) announces that the results of two US Phase III Double-blind comparative studies of Silodosin (Brand name in Japan: Urief^®), a novel drug for dysuria associated with Benign Prostatic Hyperplasia (BPH), originally developed by Kissei Pharmaceutical Co., Ltd, previously licensed-out to Watson Pharmaceuticals, Inc. (US), have been unveiled.

In two studies separately conducted in the US, in which 8 mg silodosin or placebo was given once daily for 12 weeks for BPH patients, Silodosin showed statistically significant improvements compared to placebo both in primary endpoint of the total score of the International Prostate Symptom Score-1 (IPSS-1) and secondary endpoint of maximum urine flow (Qmax). For safety, Silodosin was well tolerated in both studies.

Watson Pharmaceuticals, Inc. expects to submit a New Drug Application to the FDA in the first half of 2008 after completing ongoing long-term study and various other studies.

Urief^® is a novel, highly uroselective alpha (1A)-adrenoceptor antagonist originally developed by Kissei Pharmaceutical Co., Ltd. In Japan, Urief^® has been marketed in cooperation with Daiichi Pharmaceutical Co., Ltd. since May 11, 2006.

Urief^® reduces urethral resistance by preferentially binding to the alpha (1A) receptors mainly existing in the prostate, and thereby improves dysuria associated with BPH. Compared to previous drugs, Urief^® has features to improve urinary outlet obstruction early after dosing and to improve not only symptoms in urinary voiding but also symptoms in urinary retention. In addition, Urief^® is expected to broaden options of medication therapies for BPH because the drug showed its usefulness widely in patients with mild through severe symptoms.

＜References＞
- Overview of Watson Pharmaceuticals, Inc. -
Location of head office: California, USA
Established: 1984
Chairman and CEO: Allen Chao, Ph.D.
Net sales: 1,600 Millions US$ (2005)
No. of employees: 5,500
URL: http://www.watsonpharm.com/