Efficacy of Intravesical Instillation of Onabotulinum Toxin A in Overactive Bladder and Interstitial Cystitis/Bladder Pain Syndrome is Limited

Table of Content

Introduction

Overactive bladder (OAB) can be managed through lifestyle modification, vesical training and pelvic floor muscle training as the first-line therapy. Oral antimuscarinics and oral β3 adrenoreceptor agonists are used as second-line therapy. However, almost 50% of the patients are not relieved completely after these treatments. Several meta-analyses have reported that intravesical injection of onabotulinum toxin-A (OBTX-A) was associated with improvement in micturition, urgency and urinary incontinence. The incidence of side effects and surgical complications have been a cause of concern. Hence the efficacy of intravesical instillation of OBTX-A still remains controversial.

Aim

This systematic review and meta-analysis assessed the efficacy of intravesical instillation of OBTX-A in patients with OAB or interstitial cystitis/bladder pain syndrome (IC/BPS).

Method

Study Design

Systematic review and meta-analysis using predefined guidelines provided by the Cochrane Collaboration.

Search Strategy

  • Databases of MEDLINE, EMBASE and Cochrane Collaboration

Inclusion Criteria

  • Studies with outcome assessments including at least 1 outcome among urgency, frequency, urgency urinary incontinence (UUI), voided volume (VV), post void residual (PVR), maximum flow rate (Qmax) and patient perception of bladder condition (PPBC)
  • The studies were assessed for risk of bias
  • Follow up period of 4 weeks
  • The outcomes were compared before and after 4 weeks of treatment using the mean difference (MD)
  • Heterogeneity (I2) analysis was done. I2<25% indicated small or no level of inconsistency while I2>50% indicated insignificant inconsistency

Endpoint

  • Improvement of urgency episodes per 72 hours
  • Frequency per 72 hours
  • UUI
  • VV
  • PVR
  • Qmax
  • PPBC

Results

  • A total of 6 trials in 4 studies with 248 patients that compared instillation with OBTX-A and placebo were included for data extraction
  • The overall MD between the outcomes are shown in table 1.
Table 1. Overall MD of outcomes from baseline for OBTX-A instillation compared to placebo

Outcomes

MD

I2

Urgency episode per 72 hrs

-3.91

0%

Frequency per 24 hrs

-2.24

60.5%

UUI per 72 hrs

-2.87

82%

VV

-38.48

0%

PVR

-4.31

0%

Qmax

0.21

0%

PPBC

-0.06

0%

  • No occurrence of severe adverse events
  • Minor adverse events included urinary tract infections (UTI), dysuria and hematuria

Conclusion

  • Intravesical instillation of OBTX-A demonstrated limited efficacy with improvement of VV for the treatment of OAB or IC/BPS
  • More studies are warranted to assess the efficacy of intravesical instillation with OBTX-A in patients refractory to medication therapy and to investigate the effective drug transport

Urology. 2018 Dec 12. Pii: S0090-4295(18)31307-4. Doi: 10.1016/j.urology.2018.11.037.