Positive results from Astellas Pharma's mirabegron phase III trial in overactive bladder

Astellas Pharma US, Inc. ("Astellas Pharma US"), U.S. subsidiary of Astellas Pharma Inc. (Tokyo: TSE: 4503, "the Company"), today announced the results of a pivotal phase III clinical trial for mirabegron, the first of a new class of compounds under development for the treatment of overactive bladder (OAB), which show mirabegron significantly improves key OAB symptoms – urinary incontinence (leakage of urine) and frequency of micturition (urination) compared with placebo. These results also were associated with statistically significant improvements in patient reported outcomes (PROs). Data from this North American study are being presented for the first time in the U.S. at the American Urological Association annual meeting in Washington D.C., May 14–19, 2011, via two moderated poster sessions.

In the first poster, after 12 weeks of treatment with once daily mirabegron, significant improvements were seen from baseline to final visit in the co-primary endpoints, mean number of incontinence episodes and number of micturitions/24 hours, compared with placebo (p<0.05). Significant improvements were also recorded in the key secondary endpoints – number of incontinence episodes/24 hours, micturitions/24 hours and volume of urine voided/micturition (p<0.05 vs. placebo). Mirabegron was well tolerated with low levels of adverse events.

In the second poster, OAB patients who received once daily mirabegron reported statistically significant improvements with treatment satisfaction, symptom bother, disease perception and quality of life (particularly in subscales of coping, concern and sleep), compared with patients receiving placebo (p<0.05). PROs were assessed using the Overactive Bladder Questionnaire, Treatment Satisfaction-Visual Analog Scale and Patient Perception of Bladder Condition.

"These findings are very promising since mirabegron will represent the first oral OAB drug treatment with a new, distinct mode of action in nearly thirty years. Unlike other OAB treatments, mirabegron works by improving the storage capacity of the bladder without affecting voiding contractions. Furthermore, as patient-reported outcomes become increasingly important in the assessment of treatments for OAB, this study suggests that reductions in incontinence episodes and micturitions are associated with improved quality of life," said Dr. Victor Nitti, Vice Chairman of Urology, Professor of Urology at New York University's Langone Medical Center and principal investigator of these studies.

Mirabegron is a potent and selective beta-3 adrenoceptor agonist. Mirabegron activates beta-3 adrenoceptor on the detrusor muscle of the bladder to facilitate filling of the bladder and storage of urine. It is being developed by Astellas whose global drug, VESIcare® (solifenacin succinate) tablets, launched in 2004, is currently one of the most widely used treatments for OAB. The Company submitted a market authorization application in Japan for mirabegron in June 2010 and expects regulatory filings to the U.S. Food and Drug Administration and European Medicines Agency in the second half of 2011.

"Mirabegron will be a welcome addition to the available treatment options for OAB sufferers and represents our longstanding, broader commitment to the field of urology," said Masao Yoshida, President and CEO, Astellas Pharma US.