The safety and efficacy of botulinum toxin-A in the management of bladder oversensitivity: a randomised double-blind placebo-controlled trial.

OBJECTIVE: To assess the safety and efficacy of botulinum toxin-A (botn-A) in the management of patients with bladder oversensitivity (BO). PATIENTS AND METHODS: Twenty-three consecutive patients with a diagnosis of BO refractory to anticholinergics were enrolled in this randomised, double blind, placebo-controlled trial. Patients were randomly allocated to receive intradetrusor injections of either botn-A (100 U Botox) or saline (placebo) via a flexible cystoscopic approach. The study was designed to have 90% power to detect a change in the maximum cystometric capacity (MCC) of 30%. It was calculated that a total cohort of 58 patients would be required. Urodynamic assessment (UDS), voiding diaries (VD) and quality of life (QoL) were assessed at baseline and at 4 and 12 weeks following intervention. RESULTS: An interim analysis was performed and the trial halted after recruitment of 23 patients as a result of poorly perceived patient benefit. Data were analysed for 21 patients (10 botn-A; 11 placebo). In the treatment arm, there was a significant increase in MCC (mean rise 105 ml; p = 0.009). However, storage symptoms remained statistically unchanged following botn-A. Three patients in the treatment arm were required to perform clean intermittent self-catheterisation with no clinical improvement. The limitations of this trial include the small sample size and the unplanned interim analysis. CONCLUSIONS: This is the first randomised, double blind, placebo-controlled trial examining the effects of botn-A exclusively in patients with BO. A significant increase in MCC was observed but this did not translate to clinical benefit with no change observed in the symptoms and quality of life for the majority of patients.