Botulinum toxin type A injection for refractory interstitial cystitis: A randomized comparative study and predictors of treatment response

Abstract

Objectives: To determine whether botulinum toxin type A can represent an alternative treatment option for patients with interstitial cystitis refractory to conventional therapies. Methods: This is a single-center, prospective, open labeled, randomized comparative study. Patients with refractory interstitial cystitis were randomly divided into two groups: immediate injection (group A) or 1-month delayed injection (group B) of botulinum toxin type A after allocation. The rate of treatment response (global response assessment ≥+1: slightly improved), and changes in symptom scores and frequency volume chart variables were compared between groups 1 month after allocation. Using subjects of both groups as a single cohort, predictive factors for treatment response at 1 month post-injection and the duration of response were explored. Results: A total of 34 patients (group A n = 18, group B n = 16) were allocated. The response rate was significantly higher in group A than group B (72.2% vs 25.0%, P = 0.01). All symptom measures showed significant improvement in group A than group B. When both groups were combined as a single cohort, the response rate was 73.5% at 1 month, 58.8% at 3 months, 38.2% at 6 months and 20.6% at 12 months. The mean duration of response was 5.4 months. Multivariate analysis showed that past exposure to hydrodistension more than three times correlated with better outcomes. Conclusions: Botulinum toxin type A injection could be an alternative treatment option for patients with interstitial cystitis refractory to conventional therapies, especially for those who have received repeated hydrodistensions and transurethral fulguration.

Clinical guidelines for interstitial cystitis and hypersensitive bladder updated in 2015

“…Single-arm or randomized studies showed symptom relief by botulinum toxin injection, single or repeated, into the bladder wall. 78,79 The average duration of effect was approximately 6 months, and repeated injections seem to be necessary. It is uncertain whether the presence of Hunner lesions affects the efficacy of injection.…”

How can we improve the diagnosis and management of bladder pain syndrome? Part 2:ICI‐RS 2018

“…An ICI‐RS think tank in 2017 has evaluated the efficacy of BONT‐A in the management of BPS/IC and summarized the currently available evidence . Response rates ranged from 63% to 73.5% . BONT‐A injection in combination with hydrodistention also seems to be more efficient than hydrodistention alone .…”

Editorial Comment from Dr Tomoe to Botulinum toxin type A injection for refractory interstitial cystitis: A randomized comparative study and predictors of treatment response

“…5 As for the duration of response, if it was almost equal in IC/ BPS both with Hunner lesion and without Hunner lesion, what is BoTN-A thought to act for? It might be suggested that BoTN-A is not a disease-specific therapy.…”