Intravesical botulinum toxin-a injections reduce bladder pain of interstitial cystitis/ bladder pain syndrome refractory to conventional treatment – a prospective, multicenter, randomized, double-blind, placebo-controlled clinical trial
Yuan-Hong Jiang, Hann-Chorng Kuo
Department of Urology, Buddhist Tzu Chi General Hospital and Tzu Chi University Hualien, Taiwan
Purpose: Intravesical onabotulinumtoxinA (BoNT-A) injection is a beneficial treatment for interstitial cystitis/bladder pain syndrome (IC/BPS), yet its therapeutic efficacy remains to be validated. This study tests efficacy and safety of intravesical BoNT-A injections for treatment of IC/BPS.
Materials and Methods: A multicenter, randomized, double-blind, placebo-controlled trial in patientswith IC/BPS refractory to conventional treatment was conducted. Patients were randomized in a 2:1 ratio to hydrodistention plus suburothelial injections of BoNT-A 100U (Botox group) or the equivalent amount of normal saline (N/S group). The primary endpoint was a decrease in pain assessed using a visual analog scale (VAS) at week 8 after treatment. Secondary endpoints included voiding diary and urodynamic variables. The Wilcoxon sign rank and rank sum tests were used for statistical analyses.
Results: A total of 60 patients (8 males, 52 females, age 50.8 ±13.9 years) including 40 in the Botox and 20 in the N/S groups were enrolled. At week 8, a significantly greater reduction of pain was observed in the Botox group compared to the N/S group (-2.6 ±2.8 VS. -0.9 ±2.2, p=0.021). The other variables did not differ significantly between groups except for cystometric bladder capacitu, which was increased significantly in the Botox group. The overall success rates were 63% (26/40) in the Botox group and 15% (3/20) in the N/S group (p=0.028). Adverse events did not differ between the groups.
Conclusions: Intravesical Botox injection of 100U of BoNT-A effectively reduced bladder pain symptoms in patients with IC/BPS. The adverse events were acceptable.