American Urological Association: Overactive bladder agent demonstrates efficacy, tolerability in phase 3 trial

July 1, 2011

The selective beta3-adrenoceptor agonist mirabegron effectively improves symptoms of overactive bladder and is very safe and well tolderated, according to results of a phase 3 study.

Key Points

The selective beta3-adrenoceptor agonist mirabegron effectively improves symptoms of overactive bladder and is very safe and well tolerated, according to results of a North American phase 3 study presented at the American Urological Association annual meeting in Washington, DC.

The pivotal trial was conducted at 132 sites in the United States and Canada and randomly assigned 1,328 patients 1:1:1 to receive placebo, mirabegron, 50 mg, or mirabegron, 100 mg daily for 12 weeks.

Using data from patient diaries, change from baseline to final visit in the mean number of incontinence episodes per 24 hours and micturitions per 24 hours were analyzed as co-primary efficacy end points, and the results showed statistically significant differences favoring both mirabegron, 50 mg and 100 mg, versus placebo for both variables (incontinence: –1.47, –1.63, and –1.13, respectively; micturition: –1.66, –1.75, and –1.05, respectively).

Rates of treatment-emergent adverse events were similar in all groups (~50%), as were study withdrawals due to adverse events (~4%). Rates of serious adverse events, dry mouth, and constipation were also low and similar in mirabegron patients and controls, and the beta3-adrenoceptor agonist was not associated with any major cardiovascular events.

Other data showed treatment benefits in patient-reported outcomes, and the objective findings are consistent with outcomes from the second phase 3 study conducted in Europe, Australia, and Japan, reported lead author Victor W. Nitti, MD, of New York University Langone Medical Center, New York.

"With its efficacy and favorable safety profile, mirabegron appears to be a promising alternative to antimuscarinics to include in our armamentarium for OAB," Dr Nitti said.

Dr Nitti is a consultant/adviser to Allergan, Astellas, and Pfizer.