OnabotulinumtoxinA intravesical treatment in patients affected by overactive bladder syndrome: best practice in real-life management

Treatment of idiopathic overactive bladder with botulinum toxin: real-life results and patients' expectations

Background

Overactive bladder (OAB) is a prevalent syndrome affecting 11% to 16% of the adult population. When first-line pharmacological therapy is not effective, intradetrusorial injections of onabotulinumtoxinA (BTX-A) might have an important role in controlling symptoms. The main aim of this study was to access both the efficacy and safety of intradetrusor injections of 100U BTX-A in real clinical practice, among women with idiopathic OAB (iOAB).

Methods

Retrospective study, based on clinical diaries in 136 iOAB female patients, with or without urinary incontinence, submitted to BTX-A injections, between 2005 and 2018 in a tertiary university hospital. Positive response was considered only when the patient mentioned she had great improvement after the injection, otherwise, it was considered negative.

Results

A positive response was obtained in 90 patients (66%) after the first injection. Women with a positive response after the first treatment had 7.5 times more chances to improve with the second (P = .01). Discontinuation of the therapy after the first injection was neither dependent on the presence of incontinence at baseline (P = .73) nor it was related to age (P = .6). On univariate analyses, none of the parameters evaluated was useful of predicting successful response, although there was a trend in women who had had a previous midurethral sling surgery for stress urinary incontinence, to have a lower chance of having a positive response after the first injection (P = .06).Thirty-nine women (29%) had at least 1 adverse event, urinary tract infection, and straining to void were the most frequent. Women above 65 years old had less risk of developing a urinary tract infection (P = .04).

Conclusion

In real clinical practice, BTX-A injection is an effective (66%) and safe treatment, capable of improving quality of life. Moreover, responding to the first injection seems to predict good clinical outcomes in the second treatment. This procedure can be done with minimal restrictions.

Onabotulinumtoxin-A improves health status and urinary symptoms in subjects with refractory overactive bladder: Real-life experience

Objective:

Onabotulinumtoxin-A has been approved for wet overactive bladder refractory to anticholinergics in randomised controlled trials; however, data from real-life practice are scarce. This study was designed to assess the efficacy of intravesical onabotulinumtoxin-A injections, focusing on health status, urinary symptoms and subjective satisfaction.

Methods:

Data from consecutive patients with overactive bladder-refractory to anticholinergics treated with onabotulinumtoxin-A were prospectively collected and analysed. Standard doses (100–150 U) were used, followed by repeat sessions when clinical benefits diminished. Efficacy and safety of repeat onabotulinumtoxin-A administrations were assessed at 12-week post-injection. Clinical parameters evaluated were: change in the magnitude and frequency of incontinence, urgency and nocturia episodes, change in the number of pads used and procedural complications. Quality of life was evaluated using the 36-Item Short-Form Health Survey, Overactive Bladder Screener and Treatment Benefit Scale questionnaires.

Results:

Consecutive overactive bladder-refractory to anticholinergics patients ( n = 22) (median duration of oral therapy: 10 months) were enrolled. No intraoperative complications occurred, but two urinary retention cases were recorded. Forty-five percent of patients (10/22) were re-treated (median duration of perceived benefits: 18 months, range: 8–55 months). The number of urinary incontinence, frequency and nocturia episodes, and pads used went from 3.6, 11.3, 2.7 and 2.4 preoperatively to 1.0, 5.8, 0.7 and 0.7 postoperatively ( p < 0.005). Quality of life (36-Item Short-Form Health Survey) was significantly improved and symptom scores (Overactive Bladder Screener) were reduced, from 34.5 to 17.1 at week 12 ( p < 0.05). Eighty-seven percent of patients indicated improvement/great improvement in their condition (Treatment Benefit Scale).

Conclusion:

Intradetrusor injections of onabotulinumtoxin-A in patients with overactive bladder-refractory to anticholinergics significantly improved health status and urinary symptoms, with high subjective satisfaction.

Neuronal Activation in the Periaqueductal Gray Matter Upon Electrical Stimulation of the Bladder

Reflexes, that involve the spinobulbospinal pathway control both storage and voiding of urine. The periaqueductal gray matter (PAG), a pontine structure is part of the micturition pathway. Alteration in this pathway could lead to micturition disorders and urinary incontinence, such as the overactive bladder symptom complex (OABS). Although different therapeutic options exist for the management of OABS, these are either not effective in all patients. Part of the pathology of OABS is faulty sensory signaling about the filling status of the urinary bladder, which results in aberrant efferent signaling leading to overt detrusor contractions and the sensation of urgency and frequent voiding. In order to identify novel targets for therapy (i.e., structures in the central nervous system) and explore novel treatment modalities such as neuromodulation, we aimed at investigating which areas in the central nervous system are functionally activated upon sensory afferent stimulation of the bladder. Hence, we designed a robust protocol with multiple readout parameters including immunohistological and behavioral parameters during electrical stimulation of the rat urinary bladder. Bladder stimulation induced by electrical stimulation, below the voiding threshold, influences neural activity in: (1) the caudal ventrolateral PAG, close to the aqueduct; (2) the pontine micturition center and locus coeruleus; and (3) the superficial layers of the dorsal horn, sacral parasympathetic nucleus and central canal region of the spinal cord. In stimulated animals, a higher voiding frequency was observed but was not accompanied by increase in anxiety level and locomotor deficits. Taken together, this work establishes a critical role for the vlPAG in the processing of sensory information from the urinary bladder and urges future studies to investigate the potential of neuromodulatory approaches for urological diseases.

The role of botulinum toxin A in treating neurogenic bladder

Neurogenic detrusor overactivity (NDO) can result in lower and upper urinary tract complications and eventually even in end-stage kidney failure. Since the driving force of this clinical cascade is high bladder pressure, controlling intravesical pressure in NDO patients improves both quality of life and life-expectancy in these patients. Botulinum toxin A (BTX-A) has proven its efficacy in reducing intravesical pressure and in reducing incontinence episodes. BTX-A also improves quality of life in patients with NDO. Both onabotulinumtoxinA (Botox^®, Allergan, Irvine, USA) and abobotulinumtoxinA (Dysport^®, Ipsen, Paris, France) have a level A recommendation for NDO-treatment. The recommended dose for intradetrusor injections in NDO patients is 200 U of onabotulinumtoxinA or 500 U of abobotulinumtoxinA. The drug is generally administered extratrigonal in the detrusor muscle, via cystoscopic guided injection at 20 sites in 1 mL injections. Intradetrusor BTX-A injections are safe, with mostly local complications such as urinary tract infection and high post-void residual or retention. The effect of the toxin lasts for approximately 9 months. Repeat injections can be performed without loss of efficacy. Different injection techniques, novel ways of BTX-A administration, eliminating the need for injection or new BTX-A types with better/longer response rates could change the field in the future.