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

Summary 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 i ntravesical 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 .