Liposomal bladder instillations for IC/BPS: an open-label clinical evaluation

Bladder Pain Syndrome (BPS): A Comprehensive Review of Treatment Strategies and Management Approaches

Bladder pain Syndrome presents a multifaceted challenge in contemporary urological practice, marked by LUTS, negative behavioural, sexual, or emotional experiences, and the potential for sexual dysfunction. We meticulously explored the existing literature of conservative, non-invasive and invasive interventions, aiming to provide clinicians with a nuanced understanding of available options for comprehensive BPS management. We delve into the effectiveness and safety profiles from behavioural approaches through lifestyle changes and physical therapy, to oral or intravesical medications, until the definitive surgical treatment. The best option evaluated is the involvement of a multidisciplinary team, including urologists, urotherapists, gynaecologists, pain specialists, primary care physicians and psychologists, educating those patients regarding the condition and its chronic course and tailoring the perfect treatment for each person. Despite this, BPS remains a challenge for urologists. Indeed, our objective is to contribute to the evolving landscape of BPS management, fostering informed decision-making and personalized care for individuals grappling with this challenging condition.

Lower Urinary Tract Inflammation and Infection: Key Microbiological and Immunological Aspects

The urinary system, primarily responsible for the filtration of blood and waste, is affected by several infectious and inflammatory conditions. Focusing on the lower tract, this review outlines the physiological and immune landscape of the urethra and bladder, addressing key immunological and microbiological aspects of important infectious/inflammatory conditions. The conditions addressed include urethritis, interstitial cystitis/bladder pain syndrome, urinary tract infections, and urosepsis. Key aspects of each condition are addressed, including epidemiology, pathophysiology, and clinical considerations. Finally, therapeutic options are outlined, highlighting gaps in the knowledge and novel therapeutic approaches.

Liposome-Encapsulated Botulinum Toxin A in Treatment of Functional Bladder Disorders

Botulinum toxin A (BoNT-A) intravesical injections have been used to treat patients with refractory functional bladder disorders such as overactive bladder (OAB) and interstitial cystitis/bladder pain syndrome (IC/BPS), but the risk of adverse events and the need for repeated injections continue to prevent widespread application of this treatment. Liposomes are vesicles that comprise concentric phospholipid layers and an aqueous core; their flexible compositions enable them to adsorb and fuse with cell membranes and to deliver drugs or proteins into cells. Therefore, liposomes have been considered as promising vehicles for the less invasive delivery of BoNT-A. In previous placebo-controlled trials including patients with OAB refractory to medical treatment, it was shown that liposomal BoNT-A could significantly decrease the frequency and urgency of urination. In patients with IC/BPS, it was shown that liposomal BoNT-A could also improve bladder pain, but the therapeutic efficacy was not superior to that of the placebo. As the therapeutic mechanisms of BoNT-A include the decreased expression of nerve growth factors, P2X3 receptors, and vanilloid receptors on C-fibers, liposomal BoNT-A might play a more promising role in the treatment of bladder oversensitivity. This article features the contemporary literature regarding BoNT-A, liposomes, and liposomal BoNT-A treatment for functional bladder disorders and potential clinical applications in the future.

Nanotechnology as a tool to advance research and treatment of non-oncologic urogenital diseases

Nanotechnology represents an expanding area of research and innovation in almost every field of science, including Medicine, where nanomaterial-based products have been developed for diagnostic and therapeutic applications. Because of their small, nanoscale size, these materials exhibit unique physical and chemical properties that differ from those of each component when considered in bulk. In Nanomedicine, there is an increasing interest in harnessing these unique properties to engineer nanocarriers for the delivery of therapeutic agents. Nano-based drug delivery platforms have many advantages over conventional drug administration routes as this technology allows for local and transdermal applications of therapeutics that can bypass the first-pass metabolism, improves drug efficacy through encapsulation of hydrophobic drugs, and allows for a sustained and controlled release of encapsulated agents. In Urology, nano-based drug delivery platforms have been extensively investigated and implemented for cancer treatment. However, there is also great potential for use of nanotechnology to treat non-oncologic urogenital diseases. We provide an update on research that is paving the way for clinical translation of nanotechnology in the areas of erectile dysfunction (ED), overactive bladder (OAB), interstitial cystitis/bladder pain syndrome (IC/BPS), and catheter-associated urinary tract infections (CAUTIs). Overall, preclinical and clinical studies have proven the utility of nanomaterials both as vehicles for transdermal and intravesical delivery of therapeutic agents and for urinary catheter formulation with antimicrobial agents to treat non-oncologic urogenital diseases. Although clinical translation will be dependent on overcoming regulatory challenges, it is inevitable before there is universal adoption of this technology to treat non-oncologic urogenital diseases.

BoNT/A in the Urinary Bladder-More to the Story than Silencing of Cholinergic Nerves

Botulinum neurotoxin (BoNT/A) is an FDA and NICE approved second-line treatment for overactive bladder (OAB) in patients either not responsive or intolerant to anti-cholinergic drugs. BoNT/A acts to weaken muscle contraction by blocking release of the neurotransmitter acetyl choline (ACh) at neuromuscular junctions. However, this biological activity does not easily explain all the observed effects in clinical and non-clinical studies. There are also conflicting reports of expression of the BoNT/A protein receptor, SV2, and intracellular target protein, SNAP-25, in the urothelium and bladder. This review presents the current evidence of BoNT/A's effect on bladder sensation, potential mechanisms by which it might exert these effects and discusses recent advances in understanding the action of BoNT in bladder tissue.

Local drug delivery systems for inflammatory diseases: Status quo, challenges, and opportunities

Inflammation that is not resolved in due course becomes a chronic disease. The treatment of chronic inflammatory diseases involves a long-term use of anti-inflammatory drugs such as corticosteroids and nonsteroidal anti-inflammatory drugs, often accompanied by dose-dependent side effects. Local drug delivery systems have been widely explored to reduce their off-target side effects and the medication frequency, with several products making to the market or in development over the years. However, numerous challenges remain, and drug delivery technology is underutilized in some applications. This review showcases local drug delivery systems in different inflammatory diseases, including the targets well-known to drug delivery scientists (e.g., joints, eyes, and teeth) and other applications with untapped opportunities (e.g., sinus, bladder, and colon). In each section, we start with a brief description of the disease and commonly used therapy, introduce local drug delivery systems currently on the market or in the development stage, focusing on polymeric systems, and discuss the remaining challenges and opportunities in future product development.

Biomaterial-assisted drug delivery for interstitial cystitis/bladder pain syndrome treatment

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a chronic and painful bladder condition afflicting patients with increased urinary urgency and frequency as well as incontinence. Owing to the elusive pathogenesis of IC/BPS, obtaining effective therapeutic outcomes remains challenging. Current administrational routes such as intravesical-bladder injection improve the treatment efficacy and reduce systemic side effects. However, the bladder permeability barrier hinders drug penetration into the bladder wall to meet the desired therapeutic expectation. These issues can be addressed by encapsulating drugs into biomaterials. When appropriately exploited, they would increase the drug dwelling time in the bladder, enhance the penetration of mucosa and improve the therapeutic response of IC/BPS. In this review, we first elucidate the pathogenesis and animal models of IC/BPS. Then, we highlight recent representative biomaterial-assisted drug delivery systems for IC/BPS treatment. Finally, we discuss the challenges and outlook for further developing biomaterial-based delivery systems for IC/BPS management.

Clinical Management of Bladder Pain Syndrome/Interstitial Cystitis: A Review on Current Recommendations and Emerging Treatment Options

Bladder pain syndrome (BPS) is a chronic condition characterized by pelvic pain or pressure which is perceived to be originating from the bladder, accompanied by one or more urinary symptoms, including frequency, urgency and nocturia. The precise etiology of BPS is not fully understood. Chronic bacterial infection, defective glycosaminoglycan (GAG) layer of the bladder urothelium, inappropriate activation of mast cells in the suburothelial layer of the bladder, autoimmune-mediated mechanisms and autonomic nervous system dysfunction have all been implicated. Treatments targeted at each of these mechanisms have been developed with mixed outcomes. High-quality research into the treatment options is lacking and it is difficult to draw definite conclusions. The treatment approach is multimodal and should be patient specific, targeting the symptoms which they find most bothersome. Conservative treatment, including patient education, behavioural modification, dietary advice, stress relief and physical therapy is an essential initial management strategy for all patients. If no response is observed, oral treatments such as amitriptyline are likely to offer the greatest response. Cystoscopy is essential to phenotype patients, and Hunner lesion directed therapy with fulguration or resection can be performed at the same time. Intravesical instillation of DMSO or lidocaine, detrusor injections of botulinum toxin A and neuromodulation can be used if initial management fails to improve symptoms. Oral cyclosporin can be trialled in those experienced with its use; however, it is associated with significant adverse events and requires intense monitoring. Lastly, radical surgery should be reserved for those with severe, unremitting BPS, in which quality of life is severely affected and not improved by previously mentioned interventions. Future work investigating exact aetiological factors will help target the development of efficacious treatment options, and several promising oral and intravesical treatments are emerging.

An update on treatment options for interstitial cystitis

Interstitial cystitis or bladder pain syndrome (IC/BPS) is a chronic pelvic pain syndrome related to the urinary bladder. The ideal treatment should match as much as possible with the pathophysiologic causes of the IC/BPS, but the scarcely available evidence limits this approach, with the majority of available treatments that are primarily targeted to the control of symptoms. The treatment strategies have traditionally focused on the bladder, which is considered the primary end-organ and source of pain. Nevertheless, the growing body of evidence suggests a multifaceted nature of the disease with systemic components. In general, guidelines recommend the personalized and progressive approach, that starts from the more conservative options and then advances toward more invasive and combined treatments. The behavioral changes represent the first and most conservative steps. They can be combined with oral medications or progressively with intravesical instillation of drugs, up to more invasive techniques in a combined way. Despite the multiple available options, the optimal treatment is not easy to be found. Only further investigation on the etiopathogenetic mechanisms, taking into account the differences among subgroups, and the interaction between central and peripherical factors may allow providing a real improvement in the treatment and management of these patients.

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.

An evaluation of the pharmacotherapy for interstitial cystitis

INTRODUCTION

Interstitial cystitis (IC) and bladder pain syndrome (BPS) are chronic conditions that can be debilitating for patients. There is no consensus as to their etiology, and there are many proposed treatment algorithms. Oftentimes multimodal therapy, such as combining behavioral modification and physical therapy alongside pharmacotherapies, will be utilized. With the various treatment options available to patients and providers, there is an ever-growing need to implement evidence-based therapies.

AREAS COVERED

The authors explore the different pharmacotherapies as commonly recommended in the American Urological Association (AUA) and European Association of Urology (EAU) multitiered guidelines for IC/BPS treatment as well as other investigational therapies. Pharmacotherapies targeting bladder, pelvic, and/or systemic factors in the overall treatment of IC/BPS are discussed with a particular focus on evidence-based guideline therapies. This article also looks at emerging therapies of interest.

EXPERT OPINION

IC/BPS is a syndrome that requires a multimodal approach, including clinical phenotyping and directed therapy based on the patient's symptoms. The AUA and EAU provide guidelines for practitioners to follow, but adequate treatment requires the therapy to be targeted toward the patient's phenotypic domain.

Current Pharmacologic Approaches in Painful Bladder Research: An Update

The symptoms of interstitial cystitis (IC)/bladder pain syndrome (BPS) may have multiple causes and involve many contributing factors. Traditional treatments (intravesical instillations) have had a primary focus on the bladder as origin of symptoms without adequately considering the potential influence of other local (pelvic) or systemic factors. Systemic pharmacological treatments have had modest success. A contributing factor to the low efficacy is the lack of phenotyping the patients. Individualized treatment based on is desirable, but further phenotype categorization is needed. There seems to be general agreement that IC is a unique disease and that BPS is a syndrome with multiple pathophysiologies, but this has so far not been not been well reflected in preclinical research with the aim of finding new pharmacological treatments. Current research approaches, including anti-nerve growth factor treatment, anti-tumor necrosis factor-α treatment, activation of SHIP1 (AQX-1125), and P2X3 receptor antagonists, and α₁-adrenoceptor antagonists are potential systemic treatments, implying that not only the bladder is exposed to the administered drug, which may be beneficial if the IC/BPS is a bladder manifestation of a systemic disease, or negative (adverse effects) if it is a local bladder condition. Local treatment approaches such as the antagonism of Toll-like receptors (which still is only experimental) and intravesical liposomes (with positive proof-of-concept), may have the advantages of a low number of systemic adverse effects, but cannot be expected to have effects on symptoms generated outside the bladder. Assessment of which of the treatment approaches discussed in this review that can be developed into useful therapies requires further studies.

Interstitial cystitis intravesical therapy

Interstitial cystitis (IC) is a progressive bladder disorder that presents with symptoms of bladder urgency, frequency and pain. The aetiology of the disease remains uncertain, but it is postulated that there is an initial infective insult which damages the glycosaminoglycan (GAG) layer of the bladder urothelium. This defect allows an influx of ions, particularly potassium, which initiates an inflammatory reaction in the bladder wall, which incites the symptoms described above. Treatment initially involves behavioural and oral medication, with second line being intravesical instillation therapy. Treatment strategies focus on restoring lower urinary tract epithelial function, inhibiting neural activation, controlling allergies and relieving symptoms. In this review, current intravesical therapy will be discussed, as well as what lies on the horizon for intravesical therapy in IC.

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.

A pH-sensitive stearoyl-PEG-poly(methacryloyl sulfadimethoxine)-decorated liposome system for protein delivery: An application for bladder cancer treatment

Stealth pH-responsive liposomes for the delivery of therapeutic proteins to the bladder epithelium were prepared using methoxy-poly(ethylene glycol)5kDa-1,2-distearoyl-sn-glycero-3-phosphoethanolamine (mPEG5kDa-DSPE) and stearoyl-poly(ethylene glycol)-poly(methacryloyl sulfadimethoxine) copolymer (stearoyl-PEG-polySDM), which possesses an apparent pKa of 7.2. Liposomes of 0.2:0.6:100, 0.5:1.5:100 and 1:3:100 mPEG5kDa-DSPE/stearoyl-PEG-polySDM/(soybean phosphatidylcholine+cholesterol) molar ratios were loaded with bovine serum albumin (BSA) as a protein model. The loading capacity was 1.3% w/w BSA/lipid. At pH7.4, all liposome formulations displayed a negative zeta-potential and were stable for several days. By pH decrease or addition to mouse urine, the zeta potential strongly decreased, and the liposomes underwent a rapid size increase and aggregation. Photon correlation spectroscopy (PCS) and transmission electron microscopy (TEM) analyses showed that the extent of the aggregation depended on the stearoyl-PEG-polySDM/lipid molar ratio. Cytofluorimetric analysis and confocal microscopy showed that at pH6.5, the incubation of MB49 mouse bladder cancer cells and macrophages with fluorescein isothiocyanate-labelled-BSA (FITC-BSA) loaded and N-(Lissamine Rhodamine B sulfonyl)-1, 2-dihexadecanoyl-sn-glycero-3-phosphoethanolamine triethylammonium salt (rhodamine-DHPE) labelled 1:3:100 mPEG5kDa-DSPE/stearoyl-PEG-polySDM/lipid molar ratio liposomes resulted in a time-dependent liposome association with the cells. At pH7.4, the association of BSA-loaded liposomes with the MB49 cells and macrophages was remarkably lower than at pH6.5. Confocal images of bladder sections revealed that 2h after the instillation, liposomes at pH7.4 and control non-responsive liposomes at pH7.4 or 6.5 did not associate nor delivered FITC-BSA to the bladder epithelium. On the contrary, the pH-responsive liposome formulation set at pH6.5 and soon administered to mice by bladder instillation showed that, 2h after administration, the pH-responsive liposomes efficiently delivered the loaded FITC-BSA to the bladder epithelium.

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.

Potential Effect of Liposomes and Liposome-Encapsulated Botulinum Toxin and Tacrolimus in the Treatment of Bladder Dysfunction

Bladder drug delivery via catheter instillation is a widely used treatment for recurrence of superficial bladder cancer. Intravesical instillation of liposomal botulinum toxin has recently shown promise in the treatment of overactive bladder and interstitial cystitis/bladder pain syndrome, and studies of liposomal tacrolimus instillations show promise in the treatment of hemorrhagic cystitis. Liposomes are lipid vesicles composed of phospholipid bilayers surrounding an aqueous core that can encapsulate hydrophilic and hydrophobic drug molecules to be delivered to cells via endocytosis. This review will present new developments on instillations of liposomes and liposome-encapsulated drugs into the urinary bladder for treating lower urinary tract dysfunction.

Intravesical liposome drug delivery and IC/BPS

Intravesical therapy has previously shown to be effective in delaying or preventing recurrence of superficial bladder cancer. This local route of drug administration is now demonstrating promise in the treatment of interstitial cystitis/bladder pain syndrome (IC/BPS) with the benefit of minimal systemic side effects. Liposomes (LPs) are lipid vesicles composed of phospholipid bilayers surrounding an aqueous core. They can incorporate drug molecules, both hydrophobic and hydrophilic, and vastly improve cellular uptake of these drug molecules via endocytosis. Intravesical LPs have therapeutic effects on IC/BPS patients, mainly due to their ability to form a protective lipid film on the urothelial surface and repair the damaged urothelium. This review considers the current status of intravesical LPs and LP mediated drug delivery for the treatment of IC/BPS.

Translational approaches to the treatment of benign urologic conditions in elderly women

PURPOSE OF REVIEW

Stress urinary incontinence, overactive bladder, interstitial cystitis/painful bladder syndrome, and underactive bladder are highly prevalent among elderly women, and have significant impact on quality of life; however, existing treatments are limited and are not always successful for all patients. Researchers are investigating a multitude of new therapies to treat these conditions. This review will summarize the recent literature on investigative therapies for these conditions.

RECENT FINDINGS

Multiple new treatments are being developed for lower urinary tract dysfunction. Some of these treatments, including balloon therapy and muscle-derived stem cells for stress urinary incontinence, could provide alternatives to existing therapies. Others require further research before being used in patients, such as pudendal nerve stimulation for overactive bladder and intravesical liposomes for drug delivery in interstitial cystitis/painful bladder syndrome.

SUMMARY

Multiple new therapies are being investigated that could provide clinicians with additional tools to treat lower urinary tract disorders in millions of elderly women.

Advances in intravesical therapy for urinary tract disorders

INTRODUCTION

Intravesical therapy is a valuable option in the clinical management of urinary tract disorders such as interstitial cystitis/ painful bladder syndrome (IC/PBS) and refractory overactive bladder. This review will cover the latest advances in this field using polymer and liposomes as delivery platform for drugs, protein and nucleic acids.

AREAS COVERED

This review summarizes the significance of intravesical therapy for lower urinary tract disorders. The recent advancement of liposomes as a drug delivery platform for botulinum toxin, tacrolimus and small interfering RNA is discussed. The importance of polymers forming indwelling devices and hydrogels are also discussed, where all preparations improved efficacy parameters in rodent models. Clinical experience of treating IC/PBS with indwelling devices and liposomes are summarized and preclinical evidence about the downregulation of target gene expression in rodent bladder with liposomes complexed with siRNA is also reviewed.

EXPERT OPINION

There have been several advances in the field of intravesical therapy for improving clinical outcomes. One of the most promising research avenues is the repurposing of drugs, given previously by other routes of administration, such as tacrolimus. Intravesical therapy also opens up novel therapeutic targets with improved efficacy and safety for underactive bladder.