Randomized double-blind, active-controlled phase 3 study to assess 12-month safety and efficacy of mirabegron, a β(3)-adrenoceptor agonist, in overactive bladder. Eur Urol. 2013;63:296-305. [PMID: 23195283 DOI: 10.1016/j.eururo.2012.10.048]

[Pharmacotherapy of urinary incontinence in the elderly]

The prevalence and the incidence of Urinary Incontinence is growing. Women suffer predominantly from stress and mixed urinary incontinence and men from urge incontinence. In elderly people, the pathophysiological and the physiological change in the lower urinary tract system must be considered as well as an underlying multimorbidity. Stress urinary incontinence is among others caused by an insufficient urethral closure mechanism and urge incontinence is followed by unhibited detrusor contractions. Medical treatment is beside other important conservative options only one part of the treatment strategy in incontinence. Duloxetine, a serotonine-norepinephrine reuptake inhibitore can increase activity of the external urethral sphincter and is able to reduce incontinence episodes in up to 64 %. Antagonists of muscarinic receptors can reduce urgency, frequency and urge incontinence as well as increase bladder capacity significantly. In Germany, darifenacin, fesoterodin, oxybutynin, propiverine, solifenacin, tolterodine and trospium chloride are available to treat urge incontinence. The efficacy of these agents are almost comparable in the elderly with the exception of oxybutynin IR. However, tolerability is different and not well studied in the elderly population with the exception of fesoterodin. Side effects, especially dry mouth, dizziness and constipation often limit their use. None of the agents show ideal efficacy or tolerability in all patients. Last summer therefore a β3-agonist mirabegron was also introduced in Germany but was withdrawn.

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.

The efficacy and tolerability of mirabegron, a β3 adrenoceptor agonist, in patients with symptoms of overactive bladder

Mirabegron, is the only β-3 adrenoreceptor (AR) agonist available for the treatment of overactive bladder (OAB). To assess the efficacy and tolerability of this novel drug therapy, two phase II and six phase III Astellas-sponsored trials have been conducted with over 10,500 adults with OAB recruited. Of these, seven were randomized, double blind, 12-week placebo controlled studies and the other was for 12 months and not placebo controlled. The evidence described would suggest that mirabegron is as efficacious as most antimuscarinics, including tolterodine extended release (ER) 4 mg, compared with placebo with regard to objective measures such as reduction in number of voids per 24 hours, mean volume per void, mean number of episodes of general urinary incontinence, urgency urinary incontinence and urgency per 24 hours; and subjective measures such as severity of urgency, patient perception of bladder condition and validated continence quality of life questionnaires. Regarding tolerability, these data would suggest that patients taking mirabegron suffer a similar rate of adverse effects as those taking placebo alone, whereas the rate in those taking antimuscarinics is greater. Thus mirabegron presents a safe and effective alternative treatment to antimuscarinics for patients with OAB symptoms. Patients who may particularly benefit from mirabegron include those who are unsuitable for antimuscarinics or who have previously struggled with antimuscarinic side effects.

β3-Adrenoceptor agonists for overactive bladder syndrome: Role of translational pharmacology in a repositioning clinical drug development project

β3-Adrenoceptor agonists were originally considered as a promising drug class for the treatment of obesity and/or type 2 diabetes. When these development efforts failed, they were repositioned for the treatment of the overactive bladder syndrome. Based on the example of the β3-adrenoceptor agonist mirabegron, but also taking into consideration evidence obtained with ritobegron and solabegron, we discuss challenges facing a translational pharmacology program accompanying clinical drug development for a first-in-class molecule. Challenges included generic ones such as ligand selectivity, species differences and drug target gene polymorphisms. Challenges that are more specific included changing concepts of the underlying pathophysiology of the target condition while clinical development was under way; moreover, a paucity of public domain tools for the study of the drug target and aspects of receptor agonists as drugs had to be addressed. Nonetheless, a successful first-in-class launch was accomplished. Looking back at this translational pharmacology program, we conclude that a specifically tailored and highly flexible approach is required. However, several of the lessons learned may also be applicable to translational pharmacology programs in other indications.

Mirabegron relaxes urethral smooth muscle by a dual mechanism involving β3 -adrenoceptor activation and α1 -adrenoceptor blockade

LINKED ARTICLE

This article is commented on by Michel, M. C., pp. 429-430 of this issue. To view this commentary visit http://dx.doi.org/10.1111/bph.13379.

BACKGROUND AND PURPOSE

Mirabegron is the first β3 -adrenoceptor agonist approved for treatment of overactive bladder syndrome. This study aimed to investigate the effects of β3 -adrenoceptor agonist mirabegron in mouse urethra. The possibility that mirabegron also exerts α1 -adrenoceptor antagonism was also tested in rat smooth muscle preparations presenting α1A - (vas deferens and prostate), α1D - (aorta) and α1B -adrenoceptors (spleen).

EXPERIMENTAL APPROACH

Functional assays were carried out in mouse and rat isolated tissues. Competition assays for the specific binding of [(3) H]prazosin to membrane preparations of HEK-293 cells expressing each of the human α1 -adrenoceptors, as well as β-adrenoceptor mRNA expression and cyclic AMP measurements in mouse urethra, were performed.

KEY RESULTS

Mirabegron produced concentration-dependent urethral relaxations that were shifted to the right by the selective β3 -adrenoceptor antagonist L-748,337 but unaffected by β1 - and β2 -adrenoceptor antagonists (atenolol and ICI-118,551 respectively). Mirabegron-induced relaxations were enhanced by the PDE4 inhibitor rolipram, and the agonist stimulated cAMP synthesis. Mirabegron also produced rightward shifts in urethral contractions induced by the α1 -adrenoceptor agonist phenylephrine. Schild regression analysis revealed that mirabegron behaves as a competitive antagonist of α1 -adrenoceptors in urethra, vas deferens and prostate (α1A -adrenoceptor, pA2  ≅ 5.6) and aorta (α1D -adrenoceptor, pA2  ≅ 5.4) but not in spleen (α1B -adrenoceptor). The affinities estimated for mirabegron in functional assays were consistent with those estimated in radioligand binding with human recombinant α1A - and α1D -adrenoceptors (pKi  ≅ 6.0).

CONCLUSION AND IMPLICATIONS

The effects of mirabegron in urethral smooth muscle are the result of β3 -adrenoceptor agonism together with α1A and α1D -adrenoceptor antagonism.

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.

Practical points in the medical treatment of overactive bladder and nocturia in the elderly

The prevalence of overactive bladder (OAB) increases with age. Degeneration of the central nervous system in the elderly has been proposed as one of the pathogenic factors of OAB. Antimuscarinic therapy is effective in the treatment of OAB; however, intolerable systemic adverse events and cognitive dysfunction during treatment with nonselective antimuscarinic agents is of growing concern in elderly patients. The newly developed beta-3 adrenoceptor agonist mirabegron does not adversely affect flow rate and detrusor pressure, and its therapeutic efficacy and tolerability are similar in patients aged > 65 years and > 75 years, suggesting it might be the therapeutic choice in older patients with OAB. Nocturia can cause sleep deprivation at night and increase daytime sleepiness and loss of energy in the elderly. Desmopressin add-on therapy is effective in improving nocturia and storage symptoms. However, elderly patients with a baseline serum sodium level below the normal range are at high risk of developing significant hyponatremia.

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.

Overactive bladder

Overactive bladder syndrome is highly prevalent, and increasingly so with aging. It is characterized by the presence of urinary urgency, and can be associated with incontinence, increased voiding frequency, and nocturia. Assessment needs to exclude serious medical disorders that might present with similar symptoms, and a bladder diary is an invaluable part of understanding the presentation. Initial management is conservative, comprising education, bladder training, and advice on fluid intake. Drug therapy options include antimuscarinic medications and beta-3 adrenergic receptor agonists. Persistent overactive bladder syndrome, despite initial therapy, requires a review of the patient’s understanding of conservative management and compliance, and adjustment of medications. For refractory cases, specialist review and urodynamic testing should be considered; this may identify detrusor overactivity or increased filling sensation, and needs to exclude additional factors, such as stress incontinence and voiding dysfunction. Botulinum neurotoxin-A bladder injections can be used in severe overactivity, provided the patient is able and willing to do intermittent self-catheterisation, which is necessary in about 5% of treated patients. Sacral nerve stimulation and tibial nerve stimulation are other approaches. Major reconstructive surgery, such as augmentation cystoplasty, is rarely undertaken in modern practice but remains a possibility in extreme cases.

Mirabegron: A new option in treating overactive bladder

Antimuscarinic medications have long been the mainstay of drug treatment for overactive bladder. This article describes mirabegron, one of a new class of agents that relaxes the detrusor muscle directly via a beta3 adrenoceptor agonist. Mirabegron's efficacy on frequency, urgency, and urge incontinence was tested in several trials before its wide clinical introduction. However, caution is still needed as data are lacking on the drug's efficacy and safety in frail older adults and for long-term therapy.

Clinical Guideline for Female Lower Urinary Tract Symptoms

The "Japanese Clinical Guideline for Female Lower Urinary Tract Symptoms," published in Japan in November 2013, contains two algorithms (a primary and a specialized treatment algorithm) that are novel worldwide as they cover female lower urinary tract symptoms other than urinary incontinence. For primary treatment, necessary types of evaluation include querying the patient regarding symptoms and medical history, examining physical findings, and performing urinalysis. The types of evaluations that should be performed for select cases include evaluation with symptom/quality of life (QOL) questionnaires, urination records, residual urine measurement, urine cytology, urine culture, serum creatinine measurement, and ultrasonography. If the main symptoms are voiding/post-voiding, specialized treatment should be considered because multiple conditions may be involved. When storage difficulties are the main symptoms, the patient should be assessed using the primary algorithm. When conditions such as overactive bladder or stress incontinence are diagnosed and treatment is administered, but sufficient improvement is not achieved, the specialized algorithm should be considered. In case of specialized treatment, physiological re-evaluation, urinary tract/pelvic imaging evaluation, and urodynamic testing are conducted for conditions such as refractory overactive bladder and stress incontinence. There are two causes of voiding/post-voiding symptoms: lower urinary tract obstruction and detrusor underactivity. Lower urinary tract obstruction caused by pelvic organ prolapse may be improved by surgery.

Conjoint Urological Society of Australia and New Zealand (USANZ) and Urogynaecological Society of Australasia (UGSA) Guidelines on the management of adult non-neurogenic overactive bladder

Due to the myriad of treatment options available and the potential increase in the number of patients afflicted with overactive bladder (OAB) who will require treatment, the Female Urology Special Advisory Group (FUSAG) of the Urological Society of Australia and New Zealand (USANZ), in conjunction with the Urogynaecological Society of Australasia (UGSA), see the need to move forward and set up management guidelines for physicians who may encounter or have a special interest in the treatment of this condition. These guidelines, by utilising and recommending evidence-based data, will hopefully assist in the diagnosis, clinical assessment, and optimisation of treatment efficacy. They are divided into three sections: Diagnosis and Clinical Assessment, Conservative Management, and Surgical Management. These guidelines will also bring Australia and New Zealand in line with other regions of the world where guidelines have been established, such as the American Urological Association, European Association of Urology, International Consultation on Incontinence, and the National Institute for Health and Care Excellence guidelines of the UK.

Clinical use of the β3 adrenoceptor agonist mirabegron in patients with overactive bladder syndrome

Mirabegron is a β3 adrenoceptor agonist licensed for the treatment of overactive bladder symptoms, such as urinary urgency or urgency incontinence. β3 adrenoceptor activation causes detrusor muscle relaxation, but mirabegron may also act by binding other targets in the bladder, and it may also reduce activity in sensory nerves. Phase III clinical trials (SCORPIO, ARIES, and CAPRICORN) evaluated mirabegron at various doses, demonstrating reduction from baseline to endpoint in mean incontinence episodes and mean number of micturitions per 24 h (coprimary endpoints), along with health-related quality of life and a range of secondary measures. Efficacy was seen in many patients who had previously discontinued antimuscarinic therapy on the grounds of lack of efficacy or poor tolerability. Treatment emergent adverse effects were documented in a long-term study (TAURUS), mostly being of mild or moderate severity. The most frequent adverse effects were hypertension, dry mouth, constipation, and headache, with a lower incidence of dry mouth than for the antimuscarinic active comparator. Efficacy and safety are not substantially different in older patients. A urodynamic safety study in men showed no consistent effect on voiding function, but a small increase in postvoid residual. Use of mirabegron in combination with α-adrenergic blockers does not appear to increase adverse effects. Dose reduction is needed in people with severe renal failure, or moderate hepatic failure. Dose adjustment is not needed in relation to food intake. Ongoing research is evaluating the potential for combination therapy with antimuscarinics.

Cost effectiveness of mirabegron compared with tolterodine extended release for the treatment of adults with overactive bladder in the United Kingdom

BACKGROUND

Overactive bladder (OAB) is highly prevalent and is associated with considerable morbidity and reduced health-related quality of life. β3-adrenergic receptor (β3-AR) stimulation is a novel alternative to antimuscarinic therapy for OAB.

OBJECTIVE

The objective of this analysis was to assess the cost effectiveness of the β3-AR agonist mirabegron relative to tolterodine extended release (ER) in patients with OAB from a UK National Health Service (NHS) perspective.

METHODS

A Markov model was developed to simulate the management, course of disease, and effect of complications in OAB patients over a period of 5 years. Transition probabilities for symptom severity levels and probabilities of adverse events were estimated from the results of the randomised, double-blind SCORPIO trial in 1,987 patients with OAB. Other model inputs were derived from the literature and on assumptions based on clinical experience.

RESULTS

Total 5-year costs per patient were £1,645.62 for mirabegron 50 mg/day and £1,607.75 for tolterodine ER 4 mg/day. Mirabegron was associated with a gain of 0.009 quality-adjusted life-years (QALYs) with an additional cost of £37.88. The resulting incremental cost-effectiveness ratio (ICER) was £4,386/QALY gained. In deterministic sensitivity analyses in the general OAB population and several subgroups, ICERs remained below the generally accepted willingness-to-pay (WTP) threshold of £20,000/QALY gained. The probability of mirabegron 50 mg being cost effective relative to tolterodine ER 4 mg was 89.4 % at the same WTP threshold.

CONCLUSIONS

Mirabegron 50 mg/day is likely to be cost effective compared with tolterodine ER 4 mg/day for adult patients with OAB from a UK NHS perspective.

Postmenopausal overactive bladder

Bladder storage symptoms have a severe impact on many areas as regards the quality of life including health-related, social, psychological and working functions. Pharmacotherapy of lower urinary tract stores (LUTS) has been developed to optimize neural control of the lower urinary tract in pathologic states. The bladder can be overactive or underactive. Overactive bladder (OAB) is highly prevalent and is associated with considerable morbidity, especially in aging population. Therefore, an effective treatment of OAB must result in a meaningful reduction in urinary symptoms. Pharmacotherapy for the OAB must be individualized based on the degree of bother, medication side-effect profile, concomitant comorbidities and current medication regimen. Antimuscarinic agents will continue to represent the current gold standard for the first-line pharmacological management of OAB. Alternatively to antimuscarinic therapy, β3-adrenergic receptor agonists, due to their efficacy and favorable adverse event profile, are a novel and attractive option of pharmacological treatment of overactive bladder symptoms. A combination of selective antimuscarinic and β3-adrenergic receptor agonists, agents with the different mechanism of action, gives a new treatment option for the patient with OAB according to its harms profile. A number of putative novel therapeutic agents is under clinical evaluations that may ultimately provide alternative or combination treatment options for OAB in the nearest future.

Persistence and adherence with the new beta-3 receptor agonist, mirabegron, versus antimuscarinics in overactive bladder: Early experience in Canada

INTRODUCTION

Antimuscarinics are the principal pharmacological treatment for overactive bladder (OAB), but frequently give rise to anticholinergic side effects, such as dry mouth, a factor leading to poor persistence. The β3-adrenoceptor agonist mirabegron is devoid of significant anticholinergic activity, while being effective in OAB. We evaluated persistence and adherence with mirabegron versus antimuscarinics over 12 months.

METHODS

We obtained retrospective claims from a Canadian Private Drug Plan database for patients 18 years old and over, with a first claim for mirabegron or antimuscarinics during a 6-month index period (April-September 2013). A 6-month look-back identified those with no prior claims for OAB medication (treatment-naïve) or ≥1 prior OAB drug (treatment-experienced). Time to end of persistence (≥30 day therapy gap or switch of therapy) was evaluated over 12 months; adherence with medication (medication possession ratio) was also measured.

RESULTS

Persistence data from 19 485 patients (74% female, 92% naïve, 19.9% aged ≥65 years) showed that for experienced patients the median number of days on mirabegron was 299 days, compared with a range of 96 to 242 days for the different antimuscarinics; for naïve patients, it was 196 versus 70 to 100 days, respectively. Persistence at 12 months was for mirabegron 39% versus 14% to 35% for antimuscarinics, (experienced) and 30% mirabegron versus 14% to 21% antimuscarinics, (naïve). Patients taking mirabegron demonstrated statistically significantly greater adherence than those taking antimuscarinics.

CONCLUSION

Patients who received mirabegron remained longer on treatment than those treated with antimuscarinics, and had higher 12-month persistence and adherence rates.

Cost-Effectiveness of Mirabegron Compared with Antimuscarinic Agents for the Treatment of Adults with Overactive Bladder in the United Kingdom

BACKGROUND

Mirabegron, a first-in-class selective oral β3-adrenoceptor agonist, has similar efficacy to most antimuscarinic agents and a lower incidence of dry mouth in patients with overactive bladder (OAB).

OBJECTIVES

To evaluate the cost-effectiveness of mirabegron 50 mg compared with oral antimuscarinic agents in adults with OAB from a UK National Health Service perspective.

METHODS

A Markov model including health states for symptom severity, treatment status, and adverse events was developed. Cycle length was 1 month, and the time horizon was 5 years. Antimuscarinic comparators were tolterodine extended release, solifenacin, fesoterodine, oxybutynin extended release and immediate release (IR), darifenacin, and trospium chloride modified release. Transition probabilities for symptom severity levels and adverse events were estimated from a mirabegron trial and a mixed treatment comparison. Estimates for other inputs were obtained from published literature or expert opinion. Quality-adjusted life-years (QALYs) and total health care costs, including costs of drug acquisition, physician visits, incontinence pad use, and botox injections, were modeled. Deterministic and probabilistic sensitivity analyses were performed.

RESULTS

Base-case incremental cost-effectiveness ratios ranged from £367 (vs. solifenacin 10 mg) to £15,593 (vs. oxybutynin IR 10 mg) per QALY gained. Probabilistic sensitivity analyses showed that at a willingness-to-pay threshold of £20,000/QALY gained, the probability of mirabegron 50 mg being cost-effective ranged from 70.2% versus oxybutynin IR 10 mg to 97.8% versus darifenacin 15 mg. A limitation of our analysis is the uncertainty due to the lack of direct comparisons of mirabegron with other agents; a mixed treatment comparison using rigorous methodology provided the data for the analysis, but the studies involved showed heterogeneity.

CONCLUSIONS

Mirabegron 50 mg appears to be cost-effective compared with standard oral antimuscarinic agents for the treatment of adults with OAB from a UK National Health Service perspective.

The efficacy and safety of mirabegron compared with solifenacin in overactive bladder patients dissatisfied with previous antimuscarinic treatment due to lack of efficacy: results of a noninferiority, randomized, phase IIIb trial

OBJECTIVE

To compare the efficacy and safety of mirabegron 50 mg and solifenacin 5 mg in overactive bladder (OAB) patients dissatisfied with previous antimuscarinic treatment due to lack of efficacy.

PATIENTS AND METHODS

This randomized, double-blind, phase IIIb, noninferiority study, enrolled male and female patients aged ⩾18 years old, with symptoms of OAB for ⩾3 months, who were dissatisfied with their previous antimuscarinic drug due to lack of efficacy. A total of 1887 patients were randomized to receive mirabegron 50 mg (n = 943) or solifenacin 5 mg (n = 944) daily for 12 weeks. The primary efficacy endpoint was change from baseline to end of treatment in mean number of micturitions/24 h. Noninferiority was confirmed if the lower limit of the two-sided 95% confidence interval (CI) for the treatment difference between solifenacin and mirabegron was > -0.20. Secondary efficacy endpoints, which included change from baseline in mean number of incontinence episodes/24 h, urgency incontinence episodes/24 h, urgency episodes (grade 3 or 4)/24 h and nocturia episodes/24 h, were analyzed using analysis of covariance.

RESULTS

For the primary endpoint, adjusted mean treatment difference (95% CI) in mean number of micturitions/24 h was -0.18 (-0.42, 0.06) and therefore noninferiority of mirabegron to solifenacin was not demonstrated. Both treatments demonstrated clinically meaningful reductions in efficacy variables and were well tolerated, with a lower incidence of dry mouth with mirabegron.

CONCLUSIONS

Noninferiority of mirabegron compared with solifenacin for reduction in micturition frequency could not be demonstrated in this population of OAB patients who were dissatisfied with previous antimuscarinic therapy due to lack of efficacy. Both mirabegron and solifenacin improved key OAB symptoms with no statistically significant differences observed between the two treatments. Both drugs were well tolerated.

The Impact of Gene Polymorphisms on the Success of Anticholinergic Treatment in Children with Overactive Bladder

AIM

To determine the impact of gene polymorphisms on detrusor contraction-relaxation harmony in children with lower urinary tract symptoms (LUTS).

MATERIALS AND METHODS

Toilet trained children older than 5 years of age with LUTS and normal neurological examination underwent videourodynamic study. The control group was composed of age matched children with no voiding complaints. The study group who filled out the voiding dysfunction symptom score before and after the treatment received standard oxybutynin treatment and was reevaluated 1 year after treatment. Genomic DNA was isolated from all patients and subjected to PCR for amplification. Genotyping of ARGHEF10, ROCK2, ADRB3, and CYP3A4 was carried out with Polymerase Chain Reaction- Restriction Fragment Length Polymorphism (PCR-RFLP) method.

RESULTS

34 (45%) and 42 (55%) patients were enrolled in the study and control group, respectively. ARGEF10 GG, ADRB3 TC, and CYP3A4 AG genotype patients displayed insignificant difference between pre- and posttreatment voiding dysfunction symptom score and bladder volumes.

CONCLUSIONS

The polymorphism of genes in the cholinergic pathway did not significantly differ clinical parameters. On the other hand, polymorphic patients in the adrenergic pathway seemed to suffer from clinical disappointment. For this reason, we think that the neglected adrenergic pathway could be a new therapeutic target for the treatment of anticholinergic resistant LUTS in children.

Chapter 1: The conditions of neurogenic detrusor overactivity and overactive bladder

Overactive bladder (OAB) is a symptom syndrome consisting of urinary urgency, usually accompanied by frequency and nocturia, with or without urgency urinary incontinence (UUI), in the absence of a causative infection or pathological conditions. The prevalence of OAB is approximately 11-19% in both men and women, and leads to a significant negative effect on a patient's health-related quality of life (HRQOL). OAB is also associated with comorbidities such as urinary tract infection (UTI) and an increased risk of falls. Following behavioral therapy, anticholinergic agents are commonly prescribed, but these often fail because of lack of efficacy and/or poor tolerability. Evaluation of treatment success in OAB should include pre-defined, patient-centered goals. Patients for whom oral therapy has failed to meet such goals may be considered refractory to oral therapy and candidates for minimally invasive therapy. Neurogenic detrusor overactivity (NDO) is a bladder dysfunction frequently observed in patients with conditions such as multiple sclerosis (MS) and spinal cord injury (SCI). Increased storage pressure can put the upper urinary tract at risk of deterioration and reducing this risk is a primary aim of therapy. Urinary incontinence (UI) is reported by approximately 50% of MS patients, and most SCI patients will develop some bladder dysfunction. NDO leads to a negative impact on HRQOL, independent of the impact of the primary condition. NDO patients in whom oral therapy has failed to normalize storage pressure may be considered refractory and are candidates for minimally invasive therapy.

[Therapy of overactive bladder (OAB)]

Overactive bladder (OAB) is a symptom complex which is present in approximately 17% of the European population. It is observed in the presence or absence of incontinence (wet or dry) and is associated with a high degree of psychological stress as well as high costs for the healthcare system. Myogenic, urothelial and neurogenic factors lead to frequently unknown changes of muscular, neural and connective tissue. For the definition, etiology and diagnostics of the disease the previous continuing medical education (CME) article "Diagnosis of overactive bladder (OAB)" should be consulted. In recent years some improvements have been made in OAB-related research, in terms of pathophysiological models and new pharmacological approaches with the development of new therapeutic agents. Besides classical substances, recently approved agents are increasingly being used for the therapy of OAB. Furthermore, non-pharmaceutical approaches and surgical techniques still play an important role in the therapy of OAB.

Systematic review and metaanalysis of genetic association studies of urinary symptoms and prolapse in women

OBJECTIVE

Family studies and twin studies demonstrate that lower urinary tract symptoms and pelvic organ prolapse are heritable. This review aimed to identify genetic polymorphisms tested for an association with lower urinary tract symptoms or prolapse, and to assess the strength, consistency, and risk of bias among reported associations.

STUDY DESIGN

PubMed and HuGE Navigator were searched up to May 1, 2014, using a combination of genetic and phenotype key words, including "nocturia," "incontinence," "overactive bladder," "prolapse," and "enuresis." Major genetics, urology, and gynecology conference abstracts were searched from 2005 through 2013. We screened 889 abstracts, and retrieved 78 full texts. In all, 27 published and 7 unpublished studies provided data on polymorphisms in or near 32 different genes. Fixed and random effects metaanalyses were conducted using codominant models of inheritance. We assessed the credibility of pooled associations using the interim Venice criteria.

RESULTS

In pooled analysis, the rs4994 polymorphism of the ADRB3 gene was associated with overactive bladder (odds ratio [OR], 2.5; 95% confidence interval [CI], 1.7-3.6; n = 419). The rs1800012 polymorphism of the COL1A1 gene was associated with prolapse (OR, 1.3; 95% CI, 1.0-1.7; n = 838) and stress urinary incontinence (OR, 2.1; 95% CI, 1.4-3.2; n = 190). Other metaanalyses, including those for polymorphisms of COL3A1,LAMC1,MMP1,MMP3, and MMP9 did not show significant effects. Many studies were at high risk of bias from genotyping error or population stratification.

CONCLUSION

These metaanalyses provide moderate epidemiological credibility for associations of variation in ADRB3 with overactive bladder, and variation of COL1A1 with prolapse. Clinical testing for any of these polymorphisms cannot be recommended based on current evidence.

Diagnosis and treatment of overactive bladder (non-neurogenic) in adults: AUA/SUFU guideline amendment

PURPOSE

The purpose of this guideline amendment, herein referred to as the amendment, is to incorporate relevant newly published literature to better provide a clinical framework for the diagnosis and treatment of patients with non-neurogenic overactive bladder.

MATERIALS AND METHODS

The primary source of evidence for this guideline is the systematic review and data extraction conducted as part of the Agency for Healthcare Research and Quality Evidence Report/Technology Assessment Number 187 titled Treatment of Overactive Bladder in Women (2009). That report searched PubMed, MEDLINE®, EMBASE and CINAHL for English language studies published from January 1966 to October 2008. The AUA conducted additional literature searches to capture populations and treatments not covered in detail by the AHRQ report and relevant articles published through December 2011. The review yielded 151 treatment articles after application of inclusion/exclusion criteria. An additional systematic review conducted in February 2014 identified 72 additional articles relevant to treatment and made up the basis for the 2014 amendment.

RESULTS

The amendment focused on four topic areas: mirabegron, peripheral tibial nerve stimulation, sacral neuromodulation and BTX-A. The additional literature provided the basis for an update of current guideline statements as well as the incorporation of new guideline statements related to the overall management of adults with OAB symptoms.

CONCLUSIONS

New evidence-based statements and expert opinion supplement the original guideline published in 2012, which provided guidance for the diagnosis and overall management of OAB in adults. An integrated presentation of the OAB guideline with the current amendments is available at www.auanet.org.

Validation of the Patient Perception of Intensity of Urgency Scale in patients with lower urinary tract symptoms associated with benign prostatic hyperplasia

OBJECTIVE

To assess the reliability and validity of scores derived from the Patient Perception of Intensity of Urgency Scale (PPIUS) in patients with lower urinary tract symptoms (LUTS) associated with benign prostatic hyperplasia (BPH).

METHODS

A post hoc analysis of the phase II Solifenacin and Tamsulosin in Males with Lower Urinary Tract Symptoms Associated with Benign Prostatic Hyperplasia trial (NCT00510406), a 12-week clinical trial in men with LUTS associated with BPH, assessed the measurement properties of six PPIUS-derived scores: mean score; maximum urgency score; total urgency and frequency score (TUFS; average sum of urgency scores over 3 days); and numbers of urgency episodes, urgency episodes of grade 3 or 4, and urgency incontinence episodes. Test-retest reliability, presence of floor/ceiling effects, responsiveness to change, known-group validity, and concurrent validity were assessed for each score.

RESULTS

A total of 901 patients had at least one valid PPIUS assessment after baseline. TUFS demonstrated good test-retest reliability (intraclass correlation coefficient >0.8), discriminated between groups defined based on International Prostate Symptom Score storage score severity (known-groups validity), had high concurrent validity, and had high responsiveness to change (Guyatt's responsiveness statistic 0.88), with an absence of floor or ceiling effects. The psychometric properties of other PPIUS-derived scores were not as consistently robust and showed either low-to-moderate responsiveness, presence of a floor or ceiling effect, or low-to-moderate test-retest reliability.

CONCLUSIONS

This study shows that the PPIUS is reliable and valid in patients with LUTS associated with BPH. TUFS provided the best combination of psychometric properties of the six scores derived from the PPIUS and appeared to be an appropriate measure of urgency and frequency.

Propranolol, but not naloxone, enhances spinal reflex bladder activity and reduces pudendal inhibition in cats

This study examined the role of β-adrenergic and opioid receptors in spinal reflex bladder activity and in the inhibition induced by pudendal nerve stimulation (PNS) or tibial nerve stimulation (TNS). Spinal reflex bladder contractions were induced by intravesical infusion of 0.25% acetic acid in α-chloralose-anesthetized cats after an acute spinal cord transection (SCT) at the thoracic T9/T10 level. PNS or TNS at 5 Hz was applied to inhibit these spinal reflex contractions at 2 and 4 times the threshold intensity (T) for inducing anal or toe twitch, respectively. During a cystrometrogram (CMG), PNS at 2T and 4T significantly (P < 0.05) increased bladder capacity from 58.0 ± 4.7% to 85.8 ± 10.3% and 96.5 ± 10.7%, respectively, of saline control capacity, while TNS failed to inhibit spinal reflex bladder contractions. After administering propranolol (3 mg/kg iv, a β₁/β₂-adrenergic receptor antagonist), the effects of 2T and 4T PNS on bladder capacity were significantly (P < 0.05) reduced to 64.5 ± 9.5% and 64.7 ± 7.3%, respectively, of the saline control capacity. However, the residual PNS inhibition (about 10% increase in capacity) was still statistically significant (P < 0.05). Propranolol treatment also significantly (P = 0.0019) increased the amplitude of bladder contractions but did not change the control bladder capacity. Naloxone (1 mg/kg iv, an opioid receptor antagonist) had no effect on either spinal reflex bladder contractions or PNS inhibition. At the end of experiments, hexamethonium (10 mg/kg iv, a ganglionic blocker) significantly (P < 0.05) reduced the amplitude of the reflex bladder contractions. This study indicates an important role of β₁/β₂-adrenergic receptors in pudendal inhibition and spinal reflex bladder activity.

Mirabegron in the treatment of overactive bladder

INTRODUCTION

Mirabegron is a selective β3-adrenergic receptor agonist recently developed for the treatment of patients with overactive bladder (OAB), which offers an alternative pharmacological option to the well-established treatment with antimuscarinics (AMs).

AREAS COVERED

This review offers an explanation of the mechanism of action, of the pharmacokinetics and pharmacodynamics of mirabegron and gives readers a complete overview of Phase II and III studies on the clinical efficacy, tolerability and safety of this agent in the setting of OAB treatment.

EXPERT OPINION

Both Phase II and III trials have shown that mirabegron is efficacious and safe in treating patients with OAB. Future research should focus on the assessment of mirabegron concentrations in the CNS and on the evaluation of the potential of the combination of mirabegron with AMs. Another field for future research is represented by the investigation of the interaction of mirabegron with CYP2D6 inhibitors. Furthermore, current literature completely lacks studies on the efficacy and safety of mirabegron in the pediatric population and such trials are awaited.

Managing urinary incontinence: what works?

Urinary incontinence is a common condition, which, although not life-threatening, impairs the health-related quality of life of affected individuals. All women complaining of incontinence require a basic assessment and those with complex or refractory symptoms may benefit from urodynamic studies. Initial treatment includes lifestyle advice, behavioral modifications, bladder retraining and pelvic floor muscle training. For those women with persistent stress urinary incontinence following conservative therapy, surgical management might be considered. The development of the minimally invasive, retropubic, synthetic, mid-urethral sling procedures has revolutionized stress incontinence surgery and reduced the popularity of 'traditional' procedures, such as colposuspension and autologous fascial sling. In an attempt to reduce further the morbidity, transobturator and single-incision slings have been introduced. While antimuscarinic agents are the mainstay of the current medical management of urgency urinary incontinence, a recently developed selective β3-adrenergic receptor agonist (mirabegron) offers an alternative pharmacological option. Modalities such as intravesical botulinum toxin and neuromodulation (peripheral or sacral) are available to women with refractory urgency incontinence. Finally, when all other options have been explored and proven unsuccessful, inappropriate or not feasible, reconstructive surgery or catheter insertion might be considered as a last resort. The aim of this paper is to review conservative, medical and surgical management for urinary incontinence by using the best available evidence in the literature.

The efficacy and tolerability of the β3-adrenoceptor agonist mirabegron for the treatment of symptoms of overactive bladder in older patients

INTRODUCTION

mirabegron is a β3-adrenoceptor agonist developed for the treatment of symptoms of overactive bladder (OAB). As the prevalence of OAB increases with age, a prospective subanalysis of individual and pooled efficacy and tolerability data from three 12-week, randomised, Phase III trials, and of tolerability data from a 1-year safety trial were conducted in order to evaluate the efficacy and tolerability of mirabegron in subgroups of patients aged ≥65 and ≥75 years.

METHODS

primary efficacy outcomes were change from baseline to final visit in the mean number of incontinence episodes/24 h and the mean number of micturitions/24 h. Tolerability was assessed by the incidence of treatment-emergent adverse events (TEAEs).

RESULTS

over 12 weeks mirabegron 25 mg and 50 mg once-daily reduced the mean numbers of incontinence episodes and micturitions/24 h from baseline to final visit in patients aged ≥65 and ≥75 years. Mirabegron was well tolerated: in both age groups, hypertension and urinary tract infection were among the most common TEAEs over 12 weeks and 1 year. The incidence of dry mouth, a typical anticholinergic TEAE, was up to sixfold higher among the older patients randomised to tolterodine than any dose of mirabegron.

CONCLUSIONS

these analyses have demonstrated the efficacy of mirabegron over 12 weeks and the tolerability of mirabegron over 12 weeks and 1 year in OAB patients aged ≥65 and ≥75 years, supporting mirabegron as a therapeutic option in older patients with OAB.

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.

Mirabegron 50 mg once-daily for the treatment of symptoms of overactive bladder: an overview of efficacy and tolerability over 12 weeks and 1 year

The aim of the present review article was to summarize the efficacy and tolerability for mirabegron 50 mg over 12 weeks and 1 year versus placebo (SCORPIO) or tolterodine ER 4 mg (SCORPIO and TAURUS). After a 2-week placebo run-in, adults with overactive bladder symptoms for ≥3 months were randomized if, during a 3-day micturition diary period before baseline, they had an average of ≥8 micturitions/24 h and ≥3 urgency episodes. Efficacy end-points were change from baseline to each study visit and final visit in incontinence, micturitions, volume voided/micturition, urgency incontinence, urgency (grades 3 or 4), level of urgency and nocturia. Additional secondary efficacy variables included patient-reported outcomes. Safety variables included changes in treatment-emergent adverse events and vital signs. For SCORPIO, statistically significant improvements from baseline in efficacy variables and patient-reported outcomes were seen with mirabegron versus placebo from week 4, and were maintained over time. For TAURUS, numerical improvements in efficacy were evident from month 1, and were maintained throughout 12 months. Treatment-emergent adverse events incidence was similar between groups, except for dry mouth, which was reported by fourfold (SCORPIO) and threefold (TAURUS) more patients taking tolterodine than mirabegron. Mirabegron 50 mg for 12 weeks was associated with statistically significant improvements in objective measures of efficacy and patient-reported outcomes. At final visit, improvements with mirabegron 50 mg were statistically greater versus placebo. The efficacy profile of mirabegron 50 mg appears to be maintained over 12 months.

Safety and tolerability of the β3 -adrenoceptor agonist mirabegron, for the treatment of overactive bladder: results of a prospective pooled analysis of three 12-week randomised Phase III trials and of a 1-year randomised Phase III trial

AIMS

To evaluate the safety and tolerability of the β3 -adrenoceptor agonist, mirabegron, in patients with overactive bladder (OAB).

METHODS

Tolerability and safety data from three 12-week, randomised, placebo-controlled, double-blind, Phase III trials (Studies 046, 047 and 074) were pooled by treatment group. The three studies were of a similar design, although the assessed doses of mirabegron [25, 50 or 100 mg once daily (qd)] varied, and tolterodine extended release (ER) 4 mg was included as an active-control arm in Study 046 only. Tolerability and safety data from a 1-year, randomised, double-blind, Phase III trial (Study 049) are also presented. Safety variables included the incidence and severity of treatment-emergent adverse events (TEAEs), vital signs and electrocardiogram data.

RESULTS

Mirabegron (25, 50 or 100 mg qd) was safe and well-tolerated in patients with OAB over 12-week (n = 2736) and 1-year (n = 1632) periods. The incidence of TEAEs and treatment discontinuations as a result of TEAEs was low; the majority were mild in severity and few were serious. Hypertension, nasopharyngitis and urinary tract infection were the most common TEAEs with mirabegron. The mirabegron tolerability profile was similar to that seen with placebo and tolterodine ER 4 mg, except for dry mouth, which occurred, on average, five times less frequently with mirabegron than tolterodine ER 4 mg. In the pooled 12-week analysis, mirabegron 50 mg was associated with placebo-adjusted mean increases of 0.4-0.6 mmHg in blood pressure and approximately one beat per minute in pulse rate, both reversible upon treatment discontinuation. The incidence of Major Adverse Cardiovascular Events as adjudicated by an independent cardiovascular committee was low and similar across treatment groups.

CONCLUSION

The favourable tolerability profile of mirabegron in patients with OAB may allow improved treatment compliance compared with antimuscarinics, with important implications for patient outcomes.