A pilot randomized-controlled trial of the urodynamic efficacy of mirabegron for patients with neurogenic lower urinary tract dysfunction.

AIMS: To determine the effectiveness of mirabegron in patients with neurogenic lower urinary tract dysfunction.

METHODS: Randomized, double-blind, placebo-controlled study. Canadian patients with spinal cord injury (SCI) or multiple sclerosis (MS) with urinary symptoms and incontinence were recruited. Patients were randomized to mirabegron 25 mg (or an identical placebo) for 2 weeks at which point a dose escalation to mirabegron 50 mg (or an identical placebo) was maintained for 8 weeks. Urodynamics were performed before and after treatment. The primary outcome measure was maximum cystometric capacity (MCC). Intention to treat analysis and ANCOVA models (with adjustment for baseline values) were used and marginal means (MM) are reported; P-value <0.05 was considered significant.

RESULTS: Sixteen (9 SCI and 7 MS) patients were randomized to mirabegron and 16 (10 SCI and 6 MS) to placebo. At study completion, there was no significant difference in MCC between mirabegron and placebo (MM 305 vs 369 mL, P = 0.20). There was no significant difference in volume at first neurogenic detrusor overactivity (NDO, MM 167 vs 137 mL, P = 0.14) and peak pressure of NDO (MM 69 vs 82 cmH2 O, P = 0.25). There was no significant difference in pad weights or voiding diary parameters. There was a significantly lower symptom burden among those treated with mirabegron (total neurogenic bladder symptom score MM 29 vs 34, P = 0.047).

CONCLUSIONS: Among patients with SCI or MS, we demonstrated non-significant trends towards improvement in some urodynamic parameters with mirabegron 50 mg compared to placebo, and a significantly lower neurogenic bladder symptom burden.