Original Article

A pilot study of mirabegron added to solifenacin in the treatment of overactive bladder

  • YUICHIROH OGAWA
  • MAKOTO SHIMADA
  • KATSUKI INOUE
  • TATSUO KOBAYASHI

Pelviperineology 2013;32(2):52-54

Objectives:

The ß3 adrenergic receptor agonist mirabegron was clinically indicated as a new therapeutic drug for overactive bladder (OAB) in Japan in September 2011. However, mirabegron has yet to be investigated in detail in this context. To further characterize this agent, we administered 25 mg of mirabegron as add-on therapy to female patients with confirmed OAB who displayed persisting OAB symptoms despite receiving solifenacin and investigated clinical efficacy by comparing overactive bladder symptom scores (OABSS) and residual urine volume and determining whether adverse drug reactions were worsened at Weeks 4, 8, and 12.

Methods:

Participants in the study comprised 20 female patients with persisting symptoms of OAB despite solifenacin treatment and with OABSS 33 (and urgency score 32). Mean age was 73.4 years (range, 44-90 years).

Results:

OABSS totals were significantly improved at Week 4 and had decreased on average by 3.95±2.11 by Week 12. At Week 12, 16 (80%) of subjects achieved a reduction of ³3 points in total OABSS, and no subject showed worsening of adverse drug reactions. Urge urinary incontinence resolved in 6 of the 12 affected subjects (50%). No significant differences were present in residual urine volume, no subject reported worsening of dry mouth or constipation as an adverse drug reaction, and no subject was discontinued from treatment.

Conclusions:

Used concomitantly with an anticholinergic drug, mirabegron produced an excellent therapeutic effect in OAB and presented no safety concerns. This combination could provide a new option for patients showing OAB refractory to anticholinergic drugs or severe OAB.

Keywords: OAB; Mirabegron; Solifenacin; OABSS; UUI.