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

30 Jan, 19

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 ?3 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.