Repeated intravesical onabotulinumtoxinA injections are effective in treatment of refractory interstitial cystitis/bladder pain syndrome.

AIMS: To evaluate the efficacy and safety of repeated intravesical onabotulinumtoxinA (BoNT-A) injections for treatment of interstitial cystitis/bladder pain syndrome (IC/BPS).

PATIENTS AND METHODS: Patients confirmed to have IC/BPS and refractory to conventional treatments were treated with intravesical injections of 100 U of BoNT-A plus hydrodistention every 6 months for up to four times. Primary end-point was 6 months after the fourth BoNT-A injection. Measured parameters included O'Leary-Sant symptom score (OSS) including symptom and problem indexes (ICSI/ICPI), visual analogue score (VAS) for pain, voiding diary variables, urodynamic parameters, maximal bladder capacity (MBC), glomerulation grade, and global response assessment (GRA). Multiple measurements and Wilcoxon rank-sum test were used for comparison between groups.

RESULTS: In overall patients, GRA, OSS, ICSI and ICPI scores, VAS, functional bladder capacity (FBC) and cystometric bladder capacity (CBC) all showed significant improvement. The glomerulation grade decreased (1.77 ± 1.06 vs. 1.19 ± 1.05, p = 0.026), but MBC remained unchanged. Among 31 patients, 19 (61%) had a GRA ≥ 2 and 12 (39%) had a GRA < 2 at end-point. Patients with a GRA ≥ 2 had significantly greater changes in OSS, ICPI, VAS, FBC and CBC than patients with a GRA < 2. Extended study revealed that persistent symptomatic improvement lasted 6-12 months in seven, 13-22 months in six and 23-51 months in six after the fourth BoNT-A injection. Five women who had GRA < 2 were found to have Hunner's ulcer. Lack of control is the main limitation.

CONCLUSION: Four repeated intravesical BoNT-A injections were safe and effective for symptom and pain relief and increased bladder capacity for treatment of IC/BPS.