Botulinum a toxin/dimethyl sulfoxide bladder instillations for women with refractory idiopathic detrusor overactivity: a phase 1/2 study

Treating Lower Urinary Tract Symptoms in Older Adults: Intravesical Options

This article provides an overview of the diagnosis and the treatment of lower urinary tract symptoms in older adults complicated by the neurodegenerative changes in the micturition reflex and further confounded by age-related decline in hepatic and renal clearance raising the propensity of adverse drug reactions. The first-line drug treatment for lower urinary tract symptoms, orally administered antimuscarinics, fails to reach the equilibrium dissociation constant of muscarinic receptors even at their maximum plasma concentration and tends to evoke a half-maximal response at a muscarinic receptor occupancy of just 0.206% in the bladder with a minimal difference from exocrine glands, which raises the adverse drug reaction risk. On the contrary, intravesical antimuscarinics are instilled at concentrations 1000-fold higher than the oral maximum plasma concentration and the equilibrium dissociation constant erects a downhill concentration gradient that drives passive diffusion and achieves a mucosal concentration around ten-fold lower than the instilled concentration for a long-lasting occupation of muscarinic receptors in mucosa and sensory nerves. A high local concentration of antimuscarinics in the bladder triggers alternative mechanisms of action and is supposed to engage retrograde transport to nerve cell bodies for neuroplastic changes that underlie a long-lasting therapeutic effect, while an intrinsically lower systemic uptake of the intravesical route lowers the muscarinic receptor occupancy of exocrine glands to lower the adverse drug reaction relative to the oral route. Thus, the traditional pharmacokinetics and pharmacodynamics of oral treatment are upended by intravesical antimuscarinics to generate a dramatic improvement (~ 76%) noted in a meta-analysis of studies enrolling children with neurogenic lower urinary tract symptoms on the primary endpoint of maximum cystometric bladder capacity as well as the secondary endpoints of filling compliance and uninhibited detrusor contractions. The therapeutic success of intravesical multidose oxybutynin solution or oxybutynin entrapped in the polymer for sustained release in the pediatric population bodes well for patients with lower urinary tract symptoms at the other extreme of the age spectrum. Though generally used to predict oral drug absorption, Lipinski's rule of five can also explain the ten-fold lower systemic uptake from the bladder of positively charged trospium over oxybutynin, a tertiary amine. Chemodenervation by an intradetrusor injection of onabotulinumtoxinA is merited for patients with idiopathic overactive bladder discontinuing oral treatment because of a lack of efficacy. However, age-related peripheral neurodegeneration potentiates the adverse drug reaction risk of urinary retention that motivates the quest of liquid instillation, delivering larger fraction of onabotulinumtoxinA to the mucosa as opposed to muscle by an intradetrusor injection can also probe the neurogenic and myogenic predominance of idiopathic overactive bladder. Overall, the treatment paradigm of lower urinary tract symptoms in older adults should be tailored to individual's overall health status and the risk tolerance for adverse drug reactions.

Therapeutic Efficacy of onabotulinumtoxinA Delivered Using Various Approaches in Sensory Bladder Disorder

Cystoscopic onabotulinumtoxinA (onaBoNTA) intradetrusor injection is an efficient and durable modality for treating sensory bladder disorders. However, the inconvenience of using the cystoscopic technique and anesthesia, and the adverse effects of direct needle injection (e.g., haematuria, pain, and infections) have motivated researchers and clinicians to develop diverse injection-free procedures to improve accessibility and prevent adverse effects. However, determining suitable approaches to transfer onaBoNTA, a large molecular and hydrophilic protein, through the impermeable urothelium to reach therapeutic efficacy remains an unmet medical need. Researchers have provided potential solutions in three categories: To disrupt the barrier of the urothelium (e.g., protamine sulfate), to increase the permeability of the urothelium (e.g., electromotive drug delivery and low-energy shock wave), and to create a carrier for transportation (e.g., liposomes, thermosensitive hydrogel, and hyaluronan-phosphatidylethanolamine). Thus far, most of these novel administration techniques have not been well established in their long-term efficacy; therefore, additional clinical trials are warranted to validate the therapeutic efficacy and durability of these techniques. Finally, researchers may make progress with new combinations or biomaterials to change clinical practices in the future.

Efficacy and Safety of Noninvasive Intravesical Instillation of Onabotulinum Toxin-A for Overactive Bladder and Interstitial Cystitis/Bladder Pain Syndrome: Systematic Review and Meta-analysis

OBJECTIVE

To investigate the efficacy and safety of noninvasive intravesical instillation of onabotulinum toxin-A (OBTX-A) through systematic review and meta-analysis. Recently, several studies of noninvasive intravesical instillation of OBTX-A have been published. However, its efficacy is not well validated yet compared to well-known efficacy of minimally invasive intravesical injection of OBTX-A.

METHOD

Systematic review and meta-analysis were performed to evaluate the efficacy of noninvasive intravesical instillation of OBTX-A in patients with overactive bladder and interstitial cystitis/bladder pain syndrome by measuring outcomes such as urgency episode per 72 hours, frequency per 72 hours, urgency urinary incontinence, voided volume (VV), postvoided residual volume, maximum flow rate, and patient perception of bladder condition.

RESULT

Six trials in 4 studies that compared instillation of OBTX-A and placebo involving 248 patients (121 experimental and 127 controls) were included for final data extraction. Instillation of OBTX-A significantly increased VV, with a mean difference of 38.48 (95% confidence interval: 76.05, 0.92) compared to the placebo group. However, other outcomes showed statistically insignificant changes. Major adverse events were not reported in the group receiving intravesical instillation of OBTX-A.

CONCLUSION

Intravesical instillation of OBTX-A showed limited efficacy with improvement of VV for treatment of overactive bladder or interstitial cystitis/bladder pain syndrome. More studies are needed to overcome the efficacy of current noninvasive bladder instillation of OBTX-A regarding effective drug transport.

Current Therapeutic Strategies in Clinical Urology

The field of urology encompasses all benign and malignant disorders of the urinary tract and the male genital tract. Urological disorders convey a huge economic and patient quality-of-life burden. Hospital acquired urinary tract infections, in particular, are under scrutiny as a measure of hospital quality. Given the prevalence of these pathologies, there is much progress still to be made in available therapeutic options in order to minimize side effects and provide effective care. Current drug delivery mechanisms in urological malignancy and the benign urological conditions of overactive bladder (OAB), interstitial cystitis/bladder pain syndrome (IC/BPS), and urinary tract infection (UTI) will be reviewed herein. Both systemic and local therapies will be discussed including sustained release formulations, nanocarriers, hydrogels and other reservoir systems, as well as gene and immunotherapy. The primary focus of this review is on agents which have passed the preclinical stages of development.

The Expanding Therapeutic Utility of Botulinum Neurotoxins

Botulinum neurotoxin (BoNT) is a major therapeutic agent that is licensed in neurological indications, such as dystonia and spasticity. The BoNT family, which is produced in nature by clostridial bacteria, comprises several pharmacologically distinct proteins with distinct properties. In this review, we present an overview of the current therapeutic landscape and explore the diversity of BoNT proteins as future therapeutics. In recent years, novel indications have emerged in the fields of pain, migraine, overactive bladder, osteoarthritis, and wound healing. The study of biological effects distal to the injection site could provide future opportunities for disease-tailored BoNT therapies. However, there are some challenges in the pharmaceutical development of BoNTs, such as liquid and slow-release BoNT formulations; and, transdermal, transurothelial, and transepithelial delivery. Innovative approaches in the areas of formulation and delivery, together with highly sensitive analytical tools, will be key for the success of next generation BoNT clinical products.

Safety and Feasibility of Intravesical Instillation of Botulinum Toxin-A in Hydrogel-based Slow-release Delivery System in Patients With Interstitial Cystitis-Bladder Pain Syndrome: A Pilot Study

OBJECTIVE

To assess the feasibility and the safety of a mixture instillation of TC-3 gel, a novel reverse-thermal gelation hydrogel, and botulinum toxin-A (BTX-A) for the treatment of interstitial cystitis-bladder pain syndrome (IC/BPS). TC-3 gel-BTX-A mix is instilled into the bladder as liquid, solidifies because of body heat, and gradually dissolves to release BTX-A for several hours.

METHODS

A single intravesical instillation of 200 U BTX-A premixed with 40 mL TC-3 gel was delivered to the bladder. Adverse events and preliminary efficacy outcome measures were assessed: bladder diary, visual analog scale (VAS) for pain, and Interstitial Cystitis Symptom Index (ICSI) and Interstitial Cystitis Problem Index (ICPI) at baseline and at 2, 6, and 12 weeks.

RESULTS

A total of 15 severely symptomatic patients with IC/BPS (ICSI and ICPI score ranges 12-19 and 12-16, respectively; median VAS = 7) were enrolled (male and female = 4 and 11, ages 24-76). In terms of safety, no increase in VAS score was noted at instillation. All adverse events were transient and mild, the most common being temporary mild constipation (n = 4, 26%). The mean VAS at baseline vs week 12 was 6.6 ± 2.7 vs 5.3 ± 2.8 (P = .044). The mean ICSI and ICPI scores were reduced at week 12 compared with baseline (15.4 ± 2.4 vs 12.9 ± 4.3, P = .004, and 14.8 ± 1.4 vs 11.9 ± 4.0, P = .004, respectively). The mean number of voids per night at baseline decreased for 6 weeks (3.3 ± 2.1 vs 1.8 ± 0.9, P = .046) and then returned to baseline level at week 12.

CONCLUSION

Intravesical instillation of a TC-3 gel-BTX-A mixture is safe and tolerable. Preliminary results suggest temporary efficacy lasting for a few weeks.

Past, Present and Future of Chemodenervation with Botulinum Toxin in the Treatment of Overactive Bladder

PURPOSE

We systematically reviewed preclinical and clinical studies on bladder chemodenervation with onabotulinumtoxin A to highlight current limitations and future drug delivery approaches.

MATERIALS AND METHODS

We identified peer reviewed basic and clinical research studies of onabotulinumtoxin A in the treatment of neurogenic bladder and refractory idiopathic overactive bladder published between March 2000 and March 2016. Paired investigators independently screened 125 English language articles to identify controlled studies on onabotulinumtoxin A administration in the MEDLINE® database and abstracts presented at annual American Urological Association meetings. The review yielded an evidence base of more than 50 articles relevant to the approach of injection-free onabotulinumtoxin A chemodenervation.

RESULTS

The efficacy and safety of intradetrusor injection of onabotulinumtoxin A for the treatment of overactive bladder are sensitive to injection volume and depth, and this issue has motivated researchers to study injection-free modes of drug delivery into the bladder. Urothelial denudation with protamine sulfate or dimethyl sulfoxide, liposome encapsulated onabotulinumtoxin A and other physical approaches are being studied to increase toxin permeability and avoid intradetrusor injections. Liposome encapsulated onabotulinumtoxin A enhances toxin activity while reducing its toxin degradation. The safety and efficacy of liposome encapsulated onabotulinumtoxin A were tested in a multicenter, placebo controlled study. Although this treatment successfully reduced urinary frequency and urgency, it did not significantly reduce urgency urinary incontinence episodes.

CONCLUSIONS

Intradetrusor injection of onabotulinumtoxin A is a safe and effective treatment as reported in several large multicenter, randomized controlled trials. Injection of the toxin into the bladder wall impairs afferent and efferent nerves, but injection-free drug delivery approaches only impair the bladder afferent nerves. Further studies are needed to develop better drug delivery platforms that overcome the drawbacks of intradetrusor injection, increase patient acceptance and reduce treatment costs.

Investigational drugs for bladder pain syndrome (BPS) / interstitial cystitis (IC)

INTRODUCTION

Bladder pain syndrome (BPS)/interstitial cystitis (IC) is associated with sensory lower urinary tract symptoms. Unfortunately, many of the existing oral treatments are ineffective in most patients of BPS/IC, which is the motivation for developing new drugs and therapeutic approaches. This review covers the latest drugs that have been investigated in BPS/IC patients. Intravesical treatments offer the opportunity to directly target the painful bladder with less systemic side effects.

AREAS COVERED

In this review, the authors analyze the existing literature supporting the treatment of BPS/IC with conventional drugs including heparin, hyaluronic acid, chondroitin sulfate, and dimethylsulfoxide (DMSO). Furthermore, investigational drugs such as tanezumab and adalimumab, capable of sequestering nerve growth factor (NGF), and Tumor necrosis factor-α (TNF- α) are discussed. Investigational treatments such as liposomes, botulinum toxin (BTX), liposomal BTX, PD-0299685 (a Ca(2+) channel ɑ2δ ligand), continuous intravesical lidocaine, and AQX-1125 (a novel SHIP1 activating compound) are also covered.

EXPERT OPINION

New investigational drugs offer promising improvements in clinical outcomes for BPS/IC patients; however, BPS/IC is a chronic pain disorder that is very vulnerable to a strong placebo effect. In addition, BPS/IC is a heterogeneous disorder that can be classified into several phenotypes. Since different phenotypes of BPS/IC respond differently to systemic and intravesical treatments, the authors believe that new drugs developed for BPS/IC are more likely to meet their predetermined clinical endpoints if the inclusion/exclusion criterion is tailored to specific phenotype of BPS/IC patients.

Intravesical instillation of onabotulinum toxin A embedded in inert hydrogel in the treatment of idiopathic overactive bladder: A double-blind randomized pilot study

OBJECTIVE

It was hypothesized that increasing the time for which onabotulinum toxin A (OnabotA) is exposed to the urothelium following intravesical instillation will augment its effect. TC-3 is an inert heat-sensitive hydrogel, which creates an intravesical bulk providing a slow release of the embedded drug after instillation. The aim of this study was to evaluate the effect of OnabotA, embedded in inert TC-3 hydrogel, in patients with idiopathic overactive bladder (OAB).

METHODS

In total, 39 female patients (age 30-65, average 53.8 years) with OAB symptoms were randomized for the study into four groups, each receiving 50 ml of the following intravesical instillations: Group A, 0.9% NaCl (placebo, n = 11); Group B, TC-3 gel + 200 U OnabotA (n = 9); Group C, TC-3 gel + 200 U OnabotA + dimethyl sulfoxide (DMSO) (n = 10); and Group D, DMSO (n = 9). The parameters were compared before and 1 month after treatment.

RESULTS

When comparing parameters using conventional statistical methods (Kruskal-Wallis test), no statistically significant changes were observed within the groups. Comparison of the medians using an analysis based on the mathematical gnostics showed the superiority of the method used in Group B over the other groups in the following parameters: number of urgency grade 3 + 4 episodes/72 h, number of leakage episodes/72 h, Overactive Bladder Questionnaire total score and Patient Perception of Bladder Condition total score. Group D showed its superiority over the other groups in respect to the number of nocturia episodes/72 h.

CONCLUSIONS

The results indicate that intravesical instillation of OnabotA, embedded in TC-3 gel, could become an alternative to intramural injection for a well-selected subgroup of patients.

Comparison of OnabotulinumtoxinA Intradetrusor Injection Needle Performance with Modern Flexible Cystoscopes

INTRODUCTION

Intradetrusor injection of onabotulinumtoxinA (BTX-A) can be performed with rigid or flexible cystoscopy. The primary aim of this study was to analyze irrigant flow rate and total angle of deflection for the intradetrusor injection needles used for flexible cystoscopic injection of BTX-A to see if any needle provided a technical advantage.

METHODS

Three commercially available intradetrusor injection needles were evaluated using two modern flexible cystourethroscopes. The three needles analyzed were the NBI070 (Coloplast, Minneapolis, MN), DIS200 (Laborie, Williston, VT), and NM-101C-0427/MAJ-565/MAJ-655 (Olympus, Center Valley, PA). Angles of deflection and irrigant flow rates were calculated with an empty working channel and each injection needle in the working channel of the two flexible cystoscopes.

RESULTS

With the working channel empty, the Karl Storz 11272CU1 (KS) and Olympus CYF-V2 (O) cystoscopes had a total range of deflection of 341 degrees and 281 degrees, respectively. Total range of deflection with the KS cystoscope was reduced to 275 degrees, 250 degrees, and 311 degrees for the Coloplast NBI070, Laborie DIS200, and Olympus NM-101C-0427 needles, respectively. Total range of deflection with the O cystoscope was reduced to 195 degrees, 157 degrees, and 257 degrees for Coloplast NBI070, Laborie DIS200, and Olympus NM-101C-0427 needles, respectively. Average flow rates with an empty working channel were 5.7 mL/s and 5.5 mL/s for the KS and O cystoscopes, respectively. Mean flow rate with the KS cystoscope was reduced to 1.0 mL/s, 0.1 mL/s, and 0.7 mL/s for Coloplast NBI070, Laborie DIS200, and Olympus NM-101C-0427 needles, respectively. Mean flow rate with the O scope was reduced to 0.5 mL/s, 0.1 mL/s, and 0.4 mL/s for Coloplast NBI070, Laborie DIS200, and Olympus NM-101C-0427 needles, respectively.

CONCLUSION

Among commercially available intradetrusor BTX-A injection needles, the Olympus NM-101C-0427 allows for the greatest total range of deflection and has the greatest elasticity and flexibility. Coloplast NBI070 allows for the best flow rate.

Intravesical liposome and antisense treatment for detrusor overactivity and interstitial cystitis/painful bladder syndrome

Purpose. The following review focuses on the recent advancements in intravesical drug delivery, which brings added benefit to the therapy of detrusor overactivity and interstitial cystitis/painful bladder syndrome (IC/PBS). Results. Intravesical route is a preferred route of administration for restricting the action of extremely potent drugs like DMSO for patients of interstitial cystitis/painful bladder syndrome (IC/PBS) and botulinum toxin for detrusor overactivity. Patients who are either refractory to oral treatment or need to mitigate the adverse effects encountered with conventional routes of administration also chose this route. Its usefulness in some cases can be limited by vehicle (carrier) toxicity or short duration of action. Efforts have been underway to overcome these limitations by developing liposome platform for intravesical delivery of biotechnological products including antisense oligonucleotides. Conclusions. Adoption of forward-thinking approaches can achieve advancements in drug delivery systems targeted to future improvement in pharmacotherapy of bladder diseases. Latest developments in the field of nanotechnology can bring this mode of therapy from second line of treatment for refractory cases to the forefront of disease management.

Effect of botulinum toxin A on urothelial-release of ATP and expression of SNARE targets within the urothelium

AIMS

Botulinum neurotoxin serotype A (BoNT/A) has emerged as an effective treatment of urinary bladder overactivity. Intravesical lipotoxin (BoNT/A delivery using liposomes), which may target the urothelium, is effective in blocking acetic acid induced hyperactivity in animals. The objective of this study was to assess the possible site of toxin action within the urothelium.

METHODS

We examined expression of the toxin receptor (SV2) and its cleavage targets (SNAP-25 and SNAP-23) within urothelium as well as effects of the toxin on mechanically evoked release of ATP from cultured rat urothelial cells. ATP release was measured using the luciferin-luciferase assay; we examined expression of SNAP-23 and -25 in urothelial cells and mucosa of rat and human bladders.

RESULTS

BoNT/A (1.5 U; 1-3 hr) blocked hypotonic evoked release of urothelial ATP, without affecting morphology. The expression of protein targets for BoNT/A binding (SV2) was detected in human and rat bladder mucosa and catalytic action (SNAP-23, -25) in urothelial cells and mucosa (differed in intensity) from rat and human bladder. Incubation of cultured (rat) urothelial cells with BoNT/A decreased expression levels of both SNAP-23 (44%) and SNAP-25 (80%).

CONCLUSIONS

Our findings reveal that the bladder urothelium expresses the intracellular targets and the binding protein for cellular uptake of BoNT/A; and that the toxin is able to suppress the levels of these targets as well as hypotonic-evoked ATP release. These data raise the possibility that intravesical treatment with BoNT/A suppresses bladder reflex and sensory mechanisms by affecting a number of urothelial functions including release of transmitters.

OnabotulinumtoxinA significantly attenuates bladder afferent nerve firing and inhibits ATP release from the urothelium

OBJECTIVE

To investigate the direct effect of onabotulinumtoxinA (OnaBotA) on bladder afferent nerve activity and release of ATP and acetylcholine (ACh) from the urothelium.

MATERIALS AND METHODS

Bladder afferent nerve activity was recorded using an in vitro mouse preparation enabling simultaneous recordings of afferent nerve firing and intravesical pressure during bladder distension. Intraluminal and extraluminal ATP, ACh, and nitric oxide (NO) release were measured using the luciferin-luciferase and Amplex(®) Red assays (Molecular Probes, Carlsbad, CA, USA), and fluorometric assay kit, respectively. OnaBotA (2U), was applied intraluminally, during bladder distension, and its effect was monitored for 2 h after application. Whole-nerve activity was analysed to classify the single afferent units responding to physiological (low-threshold [LT] afferent <15 mmHg) and supra-physiological (high-threshold [HT] afferent >15 mmHg) distension pressures.

RESULTS

Bladder distension evoked reproducible pressure-dependent increases in afferent nerve firing. After exposure to OnaBotA, both LT and HT afferent units were significantly attenuated. OnaBotA also significantly inhibited ATP release from the urothelium and increased NO release.

CONCLUSION

These data indicate that OnaBotA attenuates the bladder afferent nerves involved in micturition and bladder sensation, suggesting that OnaBotA may exert its clinical effects on urinary urgency and the other symptoms of overactive bladder syndrome through its marked effect on afferent nerves.