A proof-of-concept study: Mirabegron, a new therapy for overactive bladder


  • ClinTrials.gov number: NCT01604928.
  • Eric Rovner led the peer-review process as the Associate Editor responsible for the paper.
  • C.R. Chapple is a Consultant to AMS and Lilly, a Consultant to and Researcher for ONO, a Consultant to, and Researcher and Speaker for Allergan, Astellas, Pfizer and Recordati, and am Editor-in-Chief at Neurourology and Urodynamics. Gerard Amarenco is a Consultant/Speaker and has participated in trials for Astellas, Pfizer, Astratech, Coloplast, Allergan, and has also participated in trials for Ipsen. Miguel A. López Aramburu is a Speaker for Astellas, GSK, and Almirall. Karel Everaert, is a Consultant for Allergan, Pfizer, and AMS, a Speaker for Allergan, AstraTech, Pfizer, and Astellas, has participated in trials for Allergan, Medtronic, AstraTech, Pfizer, Astellas and AMS, has received Fellowship travel grants from Allergan, Pfizer, and Astellas, and Research grants from Pfizer and Astellas. Josef Liehne and Viktor Vik have participated in trials for Astellas. Malcolm Lucas is a Speaker for Astellas, has participated in trials for Allergan, and has received Fellowship travel grants from Pfizer. Arwin Ridder and Robert Snijder are employees of Astellas. OsamuYamaguchi is a Consultant for Astellas, Pfizer, Hisamitsu, and Ferring, a Speaker for and has received Research grants from Astellas, Kyorin, Kissei, and Ono, and has participated in trials for Astellas.
  • The list of BLOSSOM Investigator Group is given in the online Appendix.



To evaluate the potential of mirabegron, a selective β3-adrenoceptor agonist, for treatment of overactive bladder (OAB) symptoms.


A multicenter, randomized, double-blind, double-dummy, parallel group, placebo and active-controlled, Phase 2, proof-of-concept study was conducted. Eligible patients (n = 314) were enrolled into a single-blind, 2-week placebo run-in period followed by a randomized, double-blind, placebo-controlled treatment period. Patients received mirabegron 100 or 150 mg twice-daily (BID), placebo or tolterodine 4 mg extended release (ER) once-daily for 4 weeks. Primary endpoint was change from baseline to end-of-treatment in mean number of micturition episodes per 24 hr. Secondary endpoints included changes in mean volume voided per micturition; mean number of urinary incontinence, urgency urinary incontinence, and urgency episodes per 24 hr; severity of urgency; nocturia, and quality of life measures. Safety parameters included adverse events, laboratory tests, electrocardiogram parameters and post-void residual volume.


Mirabegron 100 and 150 mg BID resulted in a statistically significant improvement versus placebo in mean change from baseline to end-of-treatment in the primary endpoint of micturition frequency (2.2 micturitions/24 hr vs. 1.2 micturitions/24 hr for both doses, adjusted P ≤ 0.01 for both comparisons). Mirabegron had a statistically significant effect versus placebo for most secondary endpoints, including quality of life variables. Despite a small increase in pulse rate, mirabegron demonstrated good safety and tolerability.


Mirabegron was efficacious and well tolerated in patients with OAB symptoms and heralds the first of a new class of oral pharmacological therapy for OAB for more than 30 years. Neurourol. Urodynam. 32:1116–1122, 2013. © 2013 Wiley Periodicals, Inc.