Prospective pharmacologic therapies for the overactive bladder

Urinary beta 3-adrenoceptor as a diagnostic biomarker for overactive bladder in women

This study was to investigate urinary beta 3-adrenoceptor concentration as a biomarker for overactive bladder (OAB) and predictor of treatment outcomes in women receiving the beta 3-adrenoceptor agonist mirabegron. The study comprised 50 women identified with OAB and 35 women considered as healthy controls. All women with OAB received daily dosage of 50 mg of mirabegron for 12 weeks. Bladder diaries, OAB-related questionnaires, and global response assessment scale (GRAS) data were collected. Urinary beta 3-adrenoceptor concentration was measured through enzyme-linked immunosorbent assay. All OAB-related questionnaires and GRAS indicated improved posttreatment urinary health. After mirabegron treatment, the frequency of micturition and urgency episodes decreased, but the urinary beta 3-adrenoceptor/creatinine (Cr) ratio increased. The urinary beta 3-adrenoceptor/creatinine ratio was identified as a sensitive biomarker for OAB with a confidence interval of 0.656 to 0.856 (p < 0.001). A negative correlation (- 0.431, p = 0.040) between this biomarker and health-related quality of life (HRQL) scores. The Beta 3-adrenoceptor/Cr levels increased significantly in the treatment-responsive group, while they remained unchanged in the unsatisfactory outcome group. This study shows that 12 weeks of mirabegron treatment improves OAB symptoms and HRQL. Furthermore, urinary beta 3-adrenoceptor concentration may be a diagnostic biomarker for OAB.

Updates of Overactive Bladder in Pediatrics

Overactive bladder (OAB) is clinically defined as urinary urgency with or without urinary incontinence. It is associated with daytime frequency or constipation and has a prevalence of approximately 5%-12% among 5- to 10-year-olds. The appropriate functional exchange between the pontine micturition center, periaqueductal gray matter, and prefrontal cortex is important for proper micturition control. Several studies on pediatric cases observed a link between OAB and neuropsychiatric problems, such as anxiety, depression, and attention deficit, and treatment of these comorbidities improved patient symptoms. In this review, we present the pathophysiology of OAB, its associated conditions, and aspects related to updates in OAB treatment, and we propose a step-by-step treatment approach following this sequence: behavioral therapy, medical treatment, and invasive treatment. Although anticholinergic drugs are the mainstay of OAB medical treatment, beta-3 agonists and alpha-blockers are now recommended as a result of significant advancements in pharmacologic treatment in the last 10 years. Electrical stimulation techniques and botulinum toxin are also effective and can be used, especially in conventional treatment-refractory cases.

Personalised 3D-Printed Mucoadhesive Gastroretentive Hydrophilic Matrices for Managing Overactive Bladder (OAB)

Overactive bladder (OAB) is a symptomatic complex condition characterised by frequent urinary urgency, nocturia, and urinary incontinence with or without urgency. Gabapentin is an effective treatment for OAB, but its narrow absorption window is a concern, as it is preferentially absorbed from the upper small intestine, resulting in poor bioavailability. We aimed to develop an extended release, intragastric floating system to overcome this drawback. For this purpose, plasticiser-free filaments of PEO (polyethylene oxide) and the drug (gabapentin) were developed using hot melt extrusion. The filaments were extruded successfully with 98% drug loading, possessed good mechanical properties, and successfully produced printed tablets using fused deposition modelling (FDM). Tablets were printed with varying shell numbers and infill density to investigate their floating capacity. Among the seven matrix tablet formulations, F2 (2 shells, 0% infill) showed the highest floating time, i.e., more than 10 h. The drug release rates fell as the infill density and shell number increased. However, F2 was the best performing formulation in terms of floating and release and was chosen for in vivo (pharmacokinetic) studies. The pharmacokinetic findings exhibit improved gabapentin absorption compared to the control (oral solution). Overall, it can be concluded that 3D printing technology is an easy-to-use approach which demonstrated its benefits in developing medicines based on a mucoadhesive gastroretentive strategy, improving the absorption of gabapentin with potential for the improved management of OAB.

How to choose appropriate medication for overactive bladder: Findings from the largest integrated clinical trial database analysis of mirabegron studies

Medical treatment of overactive bladder (OAB) includes antimuscarinic agents, beta-3 adrenoceptor agonist (mirabegron), or combination with both drugs. Recently, a meta-analysis reported the integrated clinical trial data from 10 phase 2–4, double-blind, 12-week mirabegron monotherapy studies. The results confirmed that mirabegron is as effective as the previously used antimuscarinic agent to treat OAB. The treatment-emergent adverse events were similar across subgroups. This article comments on this largest integrated clinical trial data analysis, and reviews the recently published literature and tries to reveal how to choose the appropriate medication for OAB. For OAB patients, starting from antimuscarinic agent is feasible. However, if the patients have risk of cognitive dysfunction, a history of constipation, dry mouth, and urinary retention, starting with mirabegron 50 mg might be more safe and appropriate. In the elderly patients with low detrusor contractility, with central nervous system lesion, and men with benign prostatic hyperplasia, starting from 25 mg mirabegron is recommended. If the treatment result is not satisfactory to the 25 mg mirabegron, increase dose to 50 mg mirabegron is appropriate. In patients who have failed from the first OAB medication either with antimuscarinics or mirabegron 50 mg, the exchange of the OAB medication to each other should be tried first. If the treatment result is still not satisfactory, a combination of antimuscarinics and mirabegron is recommended.

Shifting the treatment paradigm in idiopathic overactive bladder

PURPOSE

Overactive Bladder (OAB) is a common condition that is known to have a significant impact on Health Related Quality of Life (HRQoL). Whilst all patients will initially benefit from lifestyle modifications and behavioural therapy in the first instance drug therapy remains integral in management pathways. The purpose of this review paper is to reappraise the evidence based approach to the management of OAB in addition to exploring a new treatment algorithm for the escalation of treatment in those patients with refractory symptoms.

DESIGN

Literature Review RESULTS: Antimuscarinic drugs are currently the most commonly used medication although the introduction of mirabegron, a β3 agonist, has provided an alternative and also allowed combination therapy in those patients who have failed to improve on primary therapy or who have troublesome side effects. For those patients with symptoms of refractory OAB more invasive therapies including OnabotulinumtoxinA, sacral neuromodulation and Percutaneous Tibial Nerve Stimulation (PTNS) may be indicated.

CONCLUSION

We propose a new, evidence based, treatment algorithm for the management of OAB in patients who remain refractory to first line therapy.

Efficacy and tolerability of mirabegron compared with solifenacin for children with idiopathic overactive bladder: A preliminary study

Purpose

To compare the efficacy and tolerability of mirabegron and solifenacin in pediatric patients with idiopathic overactive bladder (OAB) and to identify factors affecting OAB symptom improvement after treatment.

Materials and Methods

We retrospectively reviewed 103 patients (5–15 years old) who visited our hospital with OAB symptoms between July 2017 and March 2019. All participants had received solifenacin or mirabegron. Those who had secondary OAB or who did not complete the frequency-volume chart either before or after treatment were excluded. The age-adjusted bladder capacity ratio was used to evaluate bladder capacity. Efficacy was assessed on the basis of patient reports and changes in the frequency-volume chart, and ≥90% reduction was regarded as “responding to medication.” Tolerability was assessed by obtaining reports from patients about the adverse effects of the drug.

Results

After the exclusion of 58 patients, 45 patients (29 in solifenacin-group and 16 in mirabegron-group) were included in the primary analysis. The age-adjusted bladder capacity ratio increased from 0.71 to 0.96 (p<0.001) and from 0.57 to 0.97 (p=0.002) after solifenacin and mirabegron use, respectively. Decreased bladder capacity before medication was associated with responding to medication (odds ratio, 7.41; p=0.044). There was no significant difference in efficacy between the two drugs. Drug-induced adverse effects were reported in only 3 (10.3%) of the solifenacin-treated patients.

Conclusions

Mirabegron showed comparable efficacy to solifenacin in pediatric patients with idiopathic OAB. Additionally, only few adverse effects were reported, suggesting that mirabegron can be a safe alternative for the treatment of idiopathic pediatric OAB.

Are there relevant animal models to set research priorities in LUTD? ICI-RS 2019

AIM

To discuss animal models of lower urinary tract disorders (LUTD) and their translational impact.

METHODS

Report of discussions based on presented literature-search based reviews relevant for the purpose.

RESULTS

Animal models can be used to investigate fundamental biological mechanisms, but also as tools to elucidate aspects of the pathogenesis of disease and to provide early evidence of any safety risk. Several different models may be required to obtain information that can have a translational impact. The term "translational research" covers not only the process of directly transferring knowledge from basic sciences to human trials to produce new drugs, devices, and treatment options for patients (T1 type translation) but also the implementation of early clinical research findings (phases I-III) into practice to improve care for patients (T2 type). Direct transfer of animal data to T2 is rarely possible, and the process often does not continue after the first trials in humans (phase I). It should be emphasized that many preclinical observations do not have (and do not need to have) immediate translational impact.

CONCLUSIONS

No single animal model can mimic the complexity of the human disease. Still, animal models can be useful for gaining information on LUT function in humans, for elucidating pathophysiological mechanisms, and for the definition of targets for future drugs to treat LUT disorders.

Attenuated regulatory function of the small-conductance Ca2+-activated K+ channel in detrusor smooth muscle cells excitability in an obese rat model

PURPOSE

Overactive bladder (OAB) is related to detrusor overactivity (DO), which is caused by the increased detrusor smooth muscle (DSM) cells excitability. Small-conductance Ca²⁺-activated K⁺ (SK) channels is a fundamental regulator of excitability and contractility in DSM cells. Obesity-related OAB is associated with the decreased expression and regulatory function of SK channels in DSM layer. However, the regulation role of SK channels in obesity-related OAB DSM cell excitability is still unknown. Here, we tested the hypothesis that obesity-related OAB is associated with reduced expression and activity of SK channels in DSM cells.

METHODS

Female Sprague-Dawley rats were fed a normal diet (ND) or a high-fat diet (HFD) and weighed after 12 weeks. We performed urodynamic study, single-cell quantitative reverse transcription-polymerase chain reaction (qRT-PCR), and patch-clamp electrophysiology.

RESULTS

Increased average body weights and urodynamically demonstrated OAB were observed in HFD rats. Single-cell qRT-PCR experiments discovered the decreased mRNA expression level of SK channel in DSM cell from HFD rats. Patch-clamp studies revealed that NS309, a SK channel activator, had an attenuated effect on membrane potential hyperpolarization in HFD DSM cells. In addition, the reduced whole cell SK channel currents were recorded in HFD DSM cells.

CONCLUSIONS

Attenuated SK channels expression and function, which results in the increased DSM cells excitability and contributes to DO, is discovered in obesity-related OAB DSM cells, suggesting that SK channels might be potential therapeutic targets to control OAB.

Avanafil Inhibits the Contractility of the Isolated Caprine Detrusor Muscle

Context:

Avanafil is a smooth muscle relaxant that is clinically used to treat erectile dysfunction. It is an inhibitor of phosphodiesterase-5 (PDE5), the enzyme that catalyzes the metabolism of cyclic guanosine monophosphate (cGMP). The inhibitory effect of avanafil on isolated detrusor muscle contractility has not been studied.

Aims:

This study investigated the inhibitory effect of avanafil on isolated caprine (goat) detrusor muscle contractility and the possible mechanisms involved.

Settings and Design:

80 mM potassium chloride (KCl)-induced contractility of the isolated goat detrusor was studied using a physiograph.

Materials and Methods:

Ten caprine detrusor strips were made to contract using 80 mM KCl before and after addition of three concentrations (10, 30, and 60 μM) of avanafil. Three reversal agents, ODQ, a guanylyl cyclase inhibitor; glibenclamide, an adenosine triphosphate (ATP)-sensitive potassium channel blocker; and iberiotoxin, a calcium-sensitive potassium (BKCa) channel blocker, were investigated for their ability to reverse the inhibitory effect of 30 μM avanafil on KCl-induced detrusor contractility.

Statistical Analysis Used:

The nonparametric statistical test, Kruskal–Wallis test, was used for the analysis of the data.

Results:

Avanafil caused a statistically significant inhibition of detrusor contractility at 30 and 60 μM concentrations. The inhibitory effect of 30 μM avanafil on detrusor contractility was significantly reversed by the addition of ODQ, glibenclamide, and iberiotoxin.

Conclusions:

Avanafil inhibits the contractility of the isolated detrusor by inhibiting PDE5, leading to raised cellular levels of cGMP. The raised levels of cGMP could have inhibited detrusor contractility by activating cGMP-dependent protein kinase, by opening ATP-sensitive potassium channels, and by opening BKCa. Avanafil could be evaluated for treating clinical conditions requiring relaxation of the detrusor like overactive bladder.

Mirabegron: a Beta-3 agonist for overactive bladder

OBJECTIVE

To review the literature regarding the efficacy and safety of mirabegron for the treatment of overactive bladder (OAB).

DATA SOURCES

A literature search was performed using MEDLINE (PubMed) prior to December 31, 2013, using the terms "mirabegron" and "randomized-controlled trial."

STUDY SELECTION/DATA EXTRACTION

All published, double-blind, randomized-controlled trials assessing mirabegron were included. Articles were reviewed and included if mirabegron was used as monotherapy and if the primary outcome analyzed drug efficacy.

DATA SYNTHESIS

The efficacy of mirabegron for the treatment of OAB has been demonstrated in the selected five randomized, placebo-controlled trials. The majority of these trials lasted 12 weeks and compared various doses of mirabegron with placebo and/or tolterodine extended-release (ER). Primary efficacy outcomes for the trials included mean number of micturitions per 24 hours and mean number of incontinence episodes per 24 hours. Included trials showed statistically significant reductions in both efficacy outcomes for various doses of mirabegron when compared with placebo.

CONCLUSION

Based on the trials reviewed, mirabegron has been efficacious in reducing mean number of micturitions and incontinence episodes per 24 hours, as well as in improving other secondary outcomes such as OAB symptoms and quality-of-life measures. Common adverse drug events seen with mirabegron include: hypertension, nasopharyngitis, urinary tract infections, headache, constipation, upper respiratory tract infection, arthralgia, diarrhea, tachycardia, abdominal pain, and fatigue. Given the efficacy and safety data currently available, mirabegron represents a reasonable alternative to antimuscarinics for patients with OAB. Future studies are needed to determine the utility of mirabegron for OAB in a variety of demographics.

Effect of high-fat diet-induced obesity on the small-conductance Ca2+-activated K+ channel function affecting the contractility of rat detrusor smooth muscle

PURPOSE

Obesity usually induces overactive bladder (OAB) associated with detrusor overactivity, which is related to increased contractility of the detrusor smooth muscle (DSM). Small-conductance Ca²⁺-activated K⁺ (SK) channels play a constitutive role in the regulation of DSM contractility. However, the role of SK channels in the DSM changes in obesity-related OAB is still unknown. Here, we tested the hypothesis that obesity-related OAB is associated with reduced expression and activity of SK channels in DSM and that SK channels activation is a potential treatment for OAB.

METHODS

Female Sprague-Dawley rats were fed a normal diet (ND) or a high-fat diet (HFD) and weighed after 12 weeks. Urodynamic studies, quantitative reverse transcription-polymerase chain reaction (qRT-PCR), and isometric tension recording were performed.

RESULTS

Increased average body weights and urodynamically demonstrated OAB were observed in HFD rats. qRT-PCR experiments revealed a decrease in the mRNA expression level of SK channel in DSM tissue of the HFD rats. Isometric tension recordings indicated an attenuated relaxation effect of NS309 on the spontaneous phasic and electrical field stimulation-induced contractions that occurred via SK channel activation in HFD DSM strips.

CONCLUSIONS

Reduced expression and activity of SK channels in the DSM contribute to obesity-related OAB, indicating that SK channels are a potential therapeutic target for OAB.

Hypovitaminosis D is an independent associated factor of overactive bladder in older adults

AIM OF THE STUDY

Urinary incontinence and vitamin D deficiency are common problems encountered in geriatric population. We aimed to investigate if there is a relationship between these conditions.

SUBJECTS AND METHOD

Among 2281 patients who were admitted to our geriatric medicine outpatient clinic spanning the last three years, 705 patients with known vitamin D status, urinary incontinence and subtype, and calcium plus vitamin D therapy data were included in statistical analysis. Patients who are using calcium plus vitamin D therapy were excluded. SPSS (Statistical Package for Social Sciences) version 15.0 for Windows was used for statistical analysis and p<0.05 was considered as statistically significant.

RESULTS

Mean age of the study population was 72.3±6.4years and 62.8% were female. Plasma vitamin D level (OR: 0.968, 95%CI: 0.943-0.993, p=0.013), MMSE (Mini Mental State Examination) score (OR: 0.944, 95%CI: 0.902-0.989, p=0.014), and serum ALP (Alkaline Phosphatase) level (OR: 0.995, 95%CI: 0.992-0.998, p=0.001) were found to be inversely correlated factors, and serum calcium level (OR: 1.772, 95%CI: 1.008-2.888, p=0.022) was found to be a positively correlated factor of overactive bladder. Considering the different clinical subtypes of urinary incontinence, only urgency incontinence was associated with lower plasma vitamin D level (p=0.013).

CONCLUSIONS

Vitamin D deficiency and insufficiency are independent associated factors for overactive bladder in older adults. This is explicable by effects of vitamin D on muscle growth and function.

Prospective Pilot Study of Mirabegron in Pediatric Patients with Overactive Bladder

BACKGROUND

Antimuscarinics are the pharmacologic mainstay of overactive bladder (OAB) management, but side effects limit their use. Mirabegron, a new molecule with a distinct mechanism of action (β3-adrenoreceptor agonist), was recently approved as monotherapy for idiopathic OAB in adults but has not been studied in the pediatric population.

OBJECTIVE

To evaluate the efficacy and safety of mirabegron to treat urinary incontinence in children with idiopathic OAB who were refractory to and/or intolerant of antimuscarinics.

DESIGN, SETTING, AND PARTICIPANTS

A prospective off-label study using mirabegron was conducted. Pediatric patients without symptom improvement under behavioral and medical therapies and/or with significant side effects with at least two different antimuscarinic agents were recruited.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Our primary outcome was better reported efficacy than with the use of prior anticholinergic medication. Secondary end points were tolerability, safety, and satisfaction. Efficacy and tolerability were assessed with voiding diaries, postvoid residuals, urine cultures, electrocardiogram, and vital signs. Families were questioned for continence, side effects, compliance, and Patient Perception of Bladder Condition (PPBC) questionnaire. The Wilcoxon rank sum test and Wilcoxon signed rank test were used for statistical analysis.

RESULTS AND LIMITATIONS

A total of 58 patients were recruited at a median age of 10.1 yr and were on mirabegron for a median of 11.5 mo. Median bladder capacity improved from 150ml to 200ml (p<0.001). Continence improved in 52 of 58, with 13 being completely dry. Median PPBC improved from 4.0 to 2.0 (p<0.001). Eight patients reported mild or moderate side effects. Absence of a placebo group is a limitation of the study.

CONCLUSIONS

Mirabegron, a novel first-in-class therapy, appeared as a safe and effective alternative for children with idiopathic OAB refractory to antimuscarinics.

PATIENT SUMMARY

We evaluated the efficacy and safety of mirabegron to treat incontinence in pediatric patients. Continence, median voided volumes, and quality of life were improved after the introduction of mirabegron, and few side effects were reported.

Oral pharmacotherapy for overactive bladder in older patients: mirabegron as a potential alternative to antimuscarinics

OBJECTIVE

Overactive bladder (OAB) is a particular challenge to treat in older adults with co-morbid conditions taking multiple medications. Antimuscarinics (e.g., solifenacin, fesoterodine) and β3-adrenergic receptor agonists (mirabegron) are similarly efficacious; however, antimuscarinics may be associated with side effects that result in poor persistence and contribute to anticholinergic burden, particularly in those taking other medications with anticholinergic properties. With a mechanism of action distinct from antimuscarinics, mirabegron has a different tolerability profile and does not contribute to anticholinergic burden. The objective of this review was to compare and contrast the tolerability profiles of antimuscarinics and mirabegron in older patients to inform practice.

METHODS

Prospective trials or retrospective subgroup analyses of antimuscarinics for the treatment of OAB in older patients were identified through a search of PubMed. Tolerability data and results of subgroup analyses of mirabegron in patients aged ≥65 and ≥75 years from a pooled analysis of three trials each of 12 weeks and a 1 year trial are described.

RESULTS

Anticholinergic adverse events (AEs) including dry mouth and constipation were more frequent with antimuscarinics versus mirabegron. In patients aged ≥65 years, dry mouth occurred with a six-fold higher incidence with tolterodine extended-release (ER) 4 mg than with mirabegron 25 mg or 50 mg over 12 weeks, and a three-fold higher incidence with tolterodine ER than mirabegron 50 mg over 1 year. Mirabegron had a low incidence of central nervous system effects. A systematic review of the cardiovascular safety profile of mirabegron has not identified any clinically significant effects on blood pressure or pulse rate at therapeutic doses amongst patients aged ≥65 years.

CONCLUSIONS

Mirabegron has a more favorable tolerability profile than antimuscarinics amongst older patients and may provide an improved benefit-to-risk ratio and therefore be considered as an alternative to antimuscarinics for older patients.

OnabotulinumtoxinA Treatment for Overactive Bladder in the Elderly: Practical Points and Future Prospects

Overactive bladder (OAB) increases with age. OAB in the elderly may be associated with increased risks of falls, fractures and mortality. Degeneration of the central nervous system in the elderly is proposed as one of the pathogenic factors for OAB. Recently, onabotulinumtoxinA (BoNT-A) 100 U has been demonstrated to be well tolerated, and it significantly improves all OAB symptoms and health-related quality of life in patients who are inadequately managed with anticholinergics. However, an increased risk of a large post-void residual volume and a lower long-term success rate were noted in frail elderly patients. Careful patient selection for BoNT-A injection treatment is important in elderly OAB patients. Patients who are frail, are elderly, have comorbidity or have a post-void residual volume >100 mL should be monitored carefully after BoNT-A injection treatment to prevent urinary retention and subsequent urinary tract infection. Use of liposomes to carry BoNT-A across the urothelial barrier decreases urgency-frequency episodes without compromising detrusor contractility and might avoid urinary tract infection. This treatment might prevent undesired detrusor underactivity after BoNT-A injection treatment, especially in elderly patients who have low detrusor contractility. For treatment of OAB in the elderly, clinicians should be aware of the balance between therapeutic efficacy and safety.

Does hypercholesterolemia affect the relaxation of the detrusor smooth muscle in rats? In vitro and in vivo studies

To evaluate the effects of hypercholesterolemia on the relaxation function of the urinary bladder, we examined the physiological mechanisms involved in the isoproterenol-induced relaxation in isolated detrusor strips in vitro and voiding behavior in vivo in rats. Adult male Sprague-Dawley rats were fed standard (control, N = 16) or 4 % cholesterol diet (hypercholesterolemia, N = 17) for 4 weeks. Concentration-response curves for isoproterenol-induced relaxations in carbachol-precontracted detrusor muscle strips were recorded. The contributions of β2- and β3-adrenoceptors and ATP-dependent and Ca(2+)-dependent potassium channels to the relaxation response were investigated by using selective adrenergic agonists salbutamol and BRL 37344 and specific potassium channel inhibitors glibenclamide and charybdotoxin, respectively. Cystometrography was performed to assess bladder function. Hypercholesterolemic rats had higher serum cholesterol and low- and high-density lipoprotein levels than the controls with no sign of atherosclerosis. Isoproterenol-induced relaxation was significantly enhanced in the hypercholesterolemia group. Preincubation with the M2 receptor antagonist attenuated the relaxation response in both groups. The relaxation responses to isoproterenol and salbutamol were similar in both groups, while BRL 37344 appeared to produce a greater relaxant effect in the hypercholesterolemic rats. Also, the inhibitory effects of potassium channel inhibitors on relaxation responses were comparable among the groups. The cystometric findings revealed that threshold and basal pressure values were higher in the hypercholesterolemia group compared with controls. We showed that hypercholesterolemia leads to greater relaxation responses to isoproterenol, appears to impair the braking function of M2 cholinergic receptors on adrenoceptor-induced relaxations in the isolated detrusor muscle, and affects the voiding function in rats.

The role of mirabegron in overactive bladder: a systematic review and meta-analysis

OBJECTIVE

To present a systematic review assessing the efficacy and safety of mirabegron for overactive bladder (OAB).

MATERIALS AND METHODS

A literature search was performed using the Cochrane Library, MEDLINE, EMBASE and Science Citation Index Expanded. The literature reviewed included meta-analyses, randomized and nonrandomized prospective studies. We utilized mean difference (MD) to measure the mean number of incontinence episodes and the mean number of micturitions, and OAB questionnaire (OAB-q) and odds ratio (OR) to measure adverse events rates. We used the Cochrane Collaboration's Review Manager 5.1 software for statistical analysis.

RESULTS

We identified six publications that strictly met our eligibility criteria. Meta-analysis of extractable data showed that mirabegron was more effective than placebo in treating OAB despite different drug dosages in the efficacy end points: mean number of incontinence episodes per 24 h (MD -0.54; 95% CI -0.63, -0.45; p = 0.001), mean number of micturitions per 24 h (MD -0.55; 95% CI -0.63, -0.47; p = 0.001), OAB-q (MD -4.49; 95% CI -6.27, -2.71; p = 0.001) and adverse events (OR 0.99; 95% CI 0.83, 1.19; p = 0.92). When compared to tolterodine, mirabegron was more effective in terms of mean number of incontinence episodes per 24 h (MD -0.25; 95% CI -0.43, -0.06; p = 0.009). However, there were no differences between mirabegron and tolterodine in mean number of micturitions per 24 h (MD -0.17; 95% CI -0.35, 0.01; p = 0.07) and OAB-q (MD -1.09; 95% CI -2.51, 0.33; p = 0.13). Mirabegron also had a lower adverse reaction rate (OR 0.9; 95% CI 0.8, 1.0; p = 0.04).

CONCLUSIONS

In this diverse population, mirabegron was an effective and safe pharmacologic therapy for OAB.

An animal study to compare the degree of the suppressive effects on the afferent pathways of micturition between tamsulosin and sildenafil

Background

Tamsulosin, an α1-adrenoceptor antagonist, and sildenafil, a phosphodiesterase (PDE) inhibitor, are reported to improve lower urinary tract symptoms including overactive bladder (OAB). This study is aimed at investing the effects of tamsulosin and sildenafil and comparing the degree of the suppressive effects on the afferent pathways of micturition between them using an animal model of OAB, the spontaneously hypertensive rat (SHR).

Results

The cystometric parameters, the basal pressure and duration of bladder contraction, were significantly increased in the SHR group as compared with the Wistar-Kyoto (WKY) group. The intercontraction interval also significantly decreased in the SHR group. In the SHR-Tam 0.01 mg/kg group and the SHR-Sil 1 mg/kg group, however, the basal pressure and duration were significantly reduced and the intercontraction interval was significantly prolonged. Moreover, the degree of the expression of c-Fos and NGF was significantly higher in the SHR group as compared with the WKY group. But it was significantly reduced in the SHR-Tam 0.01 mg/kg group and the SHR-Sil 1 mg/kg group. Furthermore, tamsulosin had a higher degree of effect as compared with sildenafil.

Conclusions

In conclusion, α1-adrenergic receptor antagonists and PDE-5 inhibitors may have an effect in improving the voiding functions through an inhibition of the neuronal activity in the afferent pathways of micturition.

Mirabegron for the treatment of overactive bladder: a prespecified pooled efficacy analysis and pooled safety analysis of three randomised, double-blind, placebo-controlled, phase III studies

INTRODUCTION

To examine pooled efficacy data from three, large phase III studies comparing mirabegron (50 and 100 mg) with placebo, and pooled safety data including additional mirabegron 25 mg and tolterodine extended release (ER) 4 mg results.

METHODS

This prespecified pooled analysis of three randomised, double-blind, placebo-controlled, 12-week studies, evaluated efficacy and safety of once-daily mirabegron 25 mg (safety analysis), 50 or 100 mg (efficacy and safety analyses) and tolterodine ER 4 mg (safety analysis) for the treatment of symptoms of overactive bladder (OAB). Co-primary efficacy measures were change from baseline to Final Visit in the mean number of incontinence episodes/24 h and mean number of micturitions/24 h. Key secondary efficacy end-points included mean number of urgency episodes/24 h and mean volume voided/micturitions, while other end-points included patient-reported outcomes according to the Treatment Satisfaction-Visual Analogue Scale (TS-VAS) and responder analyses [dry rate (posttreatment), ≥ 50% reduction in incontinence episodes/24 h, ≤ 8 micturitions/24 h (post hoc analysis)]. The safety analysis included adverse event (AE) reporting, laboratory assessments, ECG, postvoid residual volume and vital signs (blood pressure, pulse rate).

RESULTS

Mirabegron (50 and 100 mg once daily) demonstrated statistically significant improvements compared with placebo for the co-primary end-points, key secondary efficacy variables, TS-VAS and responder analyses (all comparisons p < 0.05). Mirabegron is well tolerated and demonstrates a good safety profile. The most common AEs (≥ 3%) included hypertension, nasopharyngitis and urinary tract infection (UTI); the incidence of hypertensive events and UTIs decreased with increasing dose. For mirabegron, the incidence of the bothersome antimuscarinic AE, dry mouth, was at placebo level and of a lesser magnitude than tolterodine.

CONCLUSION

The efficacy and safety of mirabegron are demonstrated in this large pooled clinical trial dataset in patients with OAB.

Urodynamics and safety of the β₃-adrenoceptor agonist mirabegron in males with lower urinary tract symptoms and bladder outlet obstruction

PURPOSE

Bladder outlet obstruction often presents as storage and voiding symptoms. We investigated urodynamic parameters in men with lower urinary tract symptoms and bladder outlet obstruction treated with the β₃ agonist mirabegron, a new therapy for overactive bladder symptoms.

MATERIALS AND METHODS

A total of 200 men 45 years old or older with lower urinary tract symptoms and bladder outlet obstruction were randomized to receive once daily mirabegron 50 mg (70) or 100 mg (65), or placebo (65) for 12 weeks. The primary urodynamic parameters assessed were change from baseline to end of treatment in maximum urinary flow and detrusor pressure at maximum urinary flow (noninferiority margins -3 ml per second and 15 cm H2O, respectively). We evaluated adverse events and vital signs.

RESULTS

Treatment with mirabegron 50 and 100 mg was noninferior to placebo based on the lower and upper limits of the 95% CI, respectively, for maximum urinary flow and detrusor pressure at maximum urinary flow. The adjusted mean difference vs placebo was 0.40 (95% CI -0.63, 1.42) and 0.62 ml per second (95% CI -0.43, 1.68) for maximum urinary flow, and -5.94 (95% CI -13.98, 2.09) and -1.39 cm H2O (95% CI -9.73, 6.96), respectively, for detrusor pressure at maximum urinary flow. The incidence of adverse events was similar for mirabegron and placebo.

CONCLUSIONS

Mirabegron did not adversely affect voiding urodynamics (maximum urinary flow and detrusor pressure at maximum urinary flow) compared with placebo after 12 weeks of treatment.

Sex differences in the physiology and pharmacology of the lower urinary tract

Sexual dimorphism is not only noticed in the prevalence of many diseases, but also in multiple physiological functions in the body. This review has summarized findings from published literature on the sex differences of the pathophysiology and pharmacology of the lower urinary tract (LUT) of humans and animals. Sex differences have been found in several key areas of the LUT, such as overactive bladder, expression and function of neurotransmitter receptors in the bladder and urethra, and micturition patterns in humans and animals. It is anticipated that this review will not only evoke renewed interest for further research on the mechanism of sex differences in the pathophysiology of the LUT (especially for overactive bladder), but might also open up the possibilities for gender-based drug development by pharmaceutical industries in order to find separate cures for men and women with diseases of the LUT.

Results of a randomized phase III trial of mirabegron in patients with overactive bladder

PURPOSE

Many patients with overactive bladder discontinue pharmacotherapy due to suboptimal efficacy or side effects. Mirabegron, a β3-adrenoceptor agonist, may offer an effective and well tolerated alternative treatment for overactive bladder.

MATERIALS AND METHODS

A randomized, double-blind, placebo controlled trial was conducted in the United States and Canada. After a 2-week placebo run-in period, adults with overactive bladder symptoms for 3 or more months were randomized 1:1:1 to receive placebo, 50 or 100 mg mirabegron once daily for 12 weeks. Efficacy data were collected via patient completed diaries and quality of life assessments. Co-primary efficacy end points were changes from baseline to final visit in mean number of incontinence episodes per 24 hours and micturitions per 24 hours. Key secondary micturition and incontinence end points were also evaluated. Safety assessments included treatment emergent adverse events, laboratory assessments, vital signs, electrocardiograms and post-void residual volume.

RESULTS

Compared to placebo, 50 and 100 mg mirabegron groups demonstrated statistically significantly greater mean decreases (95% CI) from baseline for incontinence episodes (-1.13 [-1.35, -0.91], -1.47 [-1.69, -1.25] and -1.63 [-1.86, -1.40]) and micturitions (-1.05 [-1.31, -0.79], -1.66 [-1.92, -1.40] and -1.75 [-2.01, -1.48]) per 24 hours (p <0.05). Significant improvements in all key secondary end points were observed for both mirabegron doses vs placebo. The incidence of frequently reported treatment emergent adverse events (hypertension, urinary tract infection, headache, nasopharyngitis) was similar in the mirabegron and placebo groups. Dry mouth was reported for 1.5%, 0.5% and 2.1% of patients in the placebo, 50 and 100 mg mirabegron groups, respectively.

CONCLUSIONS

Once daily mirabegron in a 50 or 100 mg dose is an effective treatment for overactive bladder symptoms with a low occurrence of side effects.

Management of mixed urinary incontinence

Mixed urinary incontinence accounts for 33% of all incontinence and is the involuntary loss of urine associated with the sensation of urgency; it is also associated with exertion, sneezing or coughing. Risk factors include vaginal delivery, obesity, age and possible genetic factors. Treatment includes lifestyle changes, behavioral therapies, medication and nerve modulation. Surgery with midurethral slings can cure both stress and urge components in 40-50% of cases. Future therapies may include new medications adapting potassium and calcium channels and more widespread use of sacral neuromodulation. This review focuses on the investigation and optimal management of mixed urinary incontinence.