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

Urinary incontinence in men: current and developing therapy options

INTRODUCTION

Urinary incontinence in men is a significant and often underappreciated problem. Men can have urgency and or stress incontinence. Urgency incontinence as part of the overactive bladder (OAB) syndrome and can often coexist with benign prostatic obstruction (BPO) in men and the initial treatment of this is conservative lifestyle changes and then medical therapy.

AREAS COVERED

This literature review aims to cover synthetic drugs currently utilised to treat urinary incontinence in men that are phase III and onwards. Neurological incontinence and surgical treatment options for male urinary incontinence are beyond the scope of this review.

EXPERT OPINION

The most common form of urinary incontinence in men is urgency incontinence secondary to an OAB, which often co-exists in men, with bladder outflow obstruction (BOO). The pharmacotherapy options to treat OAB include antimuscarinics, β3 agonists and phosphodiesterase inhibitors. Antimuscarinics and β3 agonists are effective in treating OAB, and have been found to have no increased urinary retention risk in the group of patients with co-existing BPO. Emerging medications include the alternative β3 agonists - solabegron and ritobegron. The future may include novel combinations of these therapies.

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.

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.

Patient and physician preferences for oral pharmacotherapy for overactive bladder: two discrete choice experiments

OBJECTIVE

We examined patient and treating physician (general practitioners, urologists, and [uro]gynecologists) preferences for oral pharmacotherapy (antimuscarinics and beta-3 adrenoceptor agonists) for overactive bladder to gain a deeper understanding of which attributes drive their treatment decision-making and to quantify to what extent.

RESEARCH DESIGN AND METHODS

Two separate discrete choice experiments were developed and validated using the input of patients and physicians. The patient experiment contained the following attributes: micturition frequency, incontinence, nocturia, urgency, dry mouth, constipation, increased heart rate, and increased blood pressure. The physician experiment contained two additional attributes: coping and atrial fibrillation. Both were fielded in five European countries. To allow for preference heterogeneity, utility functions were estimated using a mixed multinomial logit model.

RESULTS

A total of 442 patient and 318 physician responses were analyzed. Patients ranked the attributes based on their largest potential impact on treatment value as follows: incontinence, nocturia, risk of an increased heart rate, urgency, frequency, risk of increased blood pressure, risk of constipation, and risk of dry mouth; and physicians as follows: incontinence, urgency, nocturia, frequency, risk of dry mouth, coping, risk of increased heart rate, risk of increased blood pressure, risk of atrial fibrillation, and risk of constipation. CONCLUSION AND LIMITATIONS: In their valuations, physicians put more emphasis on increasing benefits, whereas patients put more emphasis on limiting risks of side effects. Another contrast that emerged was that patients' valuations of side effects were found to be fairly insensitive to the presented risk levels (with the exception of risk of dry mouth), whereas physicians' evaluated all side effects in a risk-level dependent manner. The obtained utility functions can be used to predict whether, to what extent, and for which reasons patients and physicians would choose one oral pharmacotherapy over another, as well as to advance shared decision-making.

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.

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.

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.

Improving Outcomes in Patients With Refractory Idiopathic and Neurogenic Detrusor Overactivity: Management Strategies

Neurogenic detrusor overactivity (NDO) is a lower urinary tract dysfunction commonly seen in rehabilitation settings. The emotional, medical, and financial consequences of NDO can be substantial and management typically requires a multidisciplinary team approach. Physiatrists need to be able to identify patients who require referral to specialists for diagnostic testing or higher-tiered treatment and need to engender open lines of communication between their patients and all treating clinicians. This requires an understanding of the evaluation, diagnosis, and treatment of neurogenic lower urinary tract dysfunctions.

Patient-reported outcomes with the β3 -adrenoceptor agonist mirabegron in a phase III trial in patients with overactive bladder

AIMS

To assess patient-reported outcomes (PROs) in patients with overactive bladder (OAB) receiving the novel β₃ -adrenoceptor agonist mirabegron.

METHODS

Data from a randomised, double-blind, controlled phase III trial in 1,987 patients aged ≥18 years with OAB symptoms for ≥3 months were analysed. Patients received placebo, mirabegron 50 or 100 mg/day, or tolterodine extended release (ER) 4 mg orally once daily for 12 weeks after a 2-week placebo run-in. Prespecified analysis of PROs (changes in OAB Questionnaire [OAB-q], Patient Perception of Bladder Condition [PPBC], and Work Productivity and Activity Impairment: Specific Health Problem [WPAI-SHP] instrument) in patients treated with mirabegron 50 mg/day, tolterodine ER 4 mg/day or placebo is reported. Post-hoc analyses of OAB-q, PPBC and the Treatment Satisfaction-Visual Analogue Scale (TS-VAS) in patients who were incontinent at baseline are also reported.

RESULTS

Significant improvements over placebo in OAB-q coping and concern from baseline to final visit were observed with mirabegron 50 mg/day. No significant improvements in these parameters were observed with tolterodine ER 4 mg/day. Mirabegron 50 mg/day significantly increased the proportion of patients showing a PPBC improvement over placebo. Mirabegron 50 mg/day also produced greater improvements in WPAI-SHP presenteeism and greater reductions in absenteeism and overall work impairment than placebo or tolterodine ER 4 mg/day. The impact of mirabegron 50 mg/day treatment on PROs in the incontinent population appears to be greater than that in the overall OAB population.

CONCLUSIONS

At the approved dose of 50 mg/day, mirabegron significantly improves OAB patients' perception of disease and quality of life, independent of whether they are incontinent at baseline. Neurourol. Urodynam. 35:987-994, 2016. © 2015 The Authors. Neurourology and Urodynamics published by Wiley Periodicals, Inc.

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.

Bladder wall thickness in women with symptoms of overactive bladder and detrusor overactivity: Results from the randomised, placebo-controlled shrink study

AIMS

Measurement of bladder wall thickness (BWT) by transvaginal ultrasound (TVUS) may be a less invasive method to diagnose overactive bladder (OAB) or detrusor overactivity (DO) and monitor response to therapy. This study assessed whether treatment with solifenacin affects BWT.

METHODS

This was a double-blind, randomised, placebo-controlled, phase 4 study. Adult women with OAB symptoms received solifenacin 5 or 10 mg or placebo once daily for 12 weeks. The co-primary endpoints were change from baseline to Week 12 in TVUS-measured BWT and urinary nerve growth factor. Only results for BWT are presented here.

RESULTS

Overall, 547 patients were randomised, 501 patients had a baseline BWT measurement, and change from baseline could be calculated for 478 patients. Mean BWT at baseline was 5.08 mm (range 2.2-11.1, SD = 1.14) and was normally distributed. A significant reduction in BWT from baseline to 12 weeks versus placebo was observed with solifenacin 5 mg (-0.42 vs. -0.16 mm, P = 0.03), but not with the 10 mg dose or with pooled solifenacin, considered the primary comparison. Both solifenacin doses were associated with improvements in efficacy and patient satisfaction endpoints versus placebo. Solifenacin was well tolerated, with dry mouth being the most common adverse event.

CONCLUSIONS

There was no consistent effect of solifenacin on BWT in women with OAB/DO, despite improvements in efficacy endpoints. This study suggests that routine clinical assessment of BWT with TVUS for monitoring the effects of OAB/DO treatment is not clinically useful. Neurourol. Urodynam. 35:819-825, 2016. © 2015 Wiley Periodicals, Inc.

New treatments for incontinence

Urinary incontinence (UI) is a common, yet underdetected and under-reported, health problem that can significantly affect quality of life. UI may also have serious medical and economic ramifications for untreated or undertreated patients, including perineal dermatitis, worsening of pressure ulcers, urinary tract infections, and falls. To prevent incontinence, the urethral sphincter must maintain adequate closure to resist the flow of urine from the bladder at all times until voluntary voiding is initiated and the bladder must accommodate increasing volumes of urine at a low pressure. UI can be categorized as a result of urethral underactivity (stress UI), bladder overactivity (urge UI), a combination of the 2 (mixed incontinence), or urethral overactivity/bladder underactivity (overflow incontinence). The main goal of therapy for the management of UI is to reduce the number of UI episodes, prevent complications, and, if possible, restore continence. This review highlights the existing treatment of stress, urge, mixed, and overflow UI in adult men and women and discusses many of the novel treatments including potential future or emerging therapies.

[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.

The effect of mirabegron on patient-related outcomes in patients with overactive bladder: the results of post hoc correlation and responder analyses using pooled data from three randomized Phase III trials

PURPOSE

To understand how improvements in the symptoms of overactive bladder (OAB) seen with the β3-adrenoceptor agonist mirabegron 50 mg, correlate with patient experience as measured by validated and standard patient-reported outcomes (PROs), and to identify whether there is overall directional consistency in the responsiveness of PROs to treatment effect.

METHODS

In a post hoc analysis of pooled data from three randomized, double-blind, placebo-controlled, 12-week Phase III trials of mirabegron 50 mg once daily, responder rates for incontinence frequency (≥50 % reduction in incontinence episodes/24 h from baseline to final visit), micturition frequency (≤8 micturitions/24 h at final visit), and PROs [minimally important differences in patient perception of bladder condition (PPBC) and subsets of the overactive bladder questionnaire (OAB-q) measuring total health-related quality of life (HRQoL), and symptom bother] were evaluated individually and in combination.

RESULTS

Mirabegron 50 mg demonstrated greater improvement from baseline to final visit than placebo for each of the responder analyses, whether for individual objective and subjective outcomes or combinations thereof. These improvements versus placebo were statistically significant for all double and triple responder analyses and for all single responder analyses except PPBC. PRO measurements showed directional consistency and significant correlations, and there were also significant correlations between objective and subjective measures of efficacy.

CONCLUSIONS

The improvements in objective measures seen with mirabegron 50 mg translate into a meaningful clinical benefit as evident by the directional consistency seen in HRQoL measures of benefit.

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.

Tolterodine extended release in the treatment of male OAB/storage LUTS: a systematic review

Background

Overactive bladder (OAB)/ storage lower urinary tract symptoms (LUTS) have a high prevalence affecting up to 90% of men over 80 years. The role of sufficient therapies appears crucial. In the present review, we analyzed the mechanism of action of tolterodine extended-release (ER) with the aim to clarify its efficacy and safety profile, as compared to other active treatments of OAB/storage LUTS.

Methods

A wide Medline search was performed including the combination of following words: “LUTS”, “BPH”, “OAB”, “antimuscarinic”, “tolterodine”, “tolterodine ER”. IPSS, IPSS storage sub-score and IPSS QoL (International Prostate Symptom Score) were the validated efficacy outcomes. In addition, the numbers of urgency episodes/24 h, urgency incontinence episodes/24 h, incontinence episodes/24 h and pad use were considered. We also evaluated the most common adverse events (AEs) reported for tolterodine ER.

Results

Of 128 retrieved articles, 109 were excluded. The efficacy and tolerability of tolterodine ER Vs. tolterodine IR have been evaluated in a multicenter, double-blind, randomized placebo controlled study in 1529 patients with OAB. A 71% mean reduction in urgency incontinence episodes was found in the tolterodine ER group compared to a 60% reduction in the tolterodine IR (p < 0.05). Few studies evaluated the clinical efficacy of α-blocker/tolterodine combination therapy. In patients with large prostates (prostate volume >29 cc) only the combination therapy significantly reduced 24-h voiding frequency (2.8 vs. 1.7 with tamsulosin, 1.4 with tolterodine, or 1.6 with placebo). A recent meta-analysis evaluating tolterodine in comparison with other antimuscarinic drugs demonstrated that tolterodine ER was significantly more effective than placebo in reducing micturition/24 h, urinary leakage episodes/24 h, urgency episodes/24 h, and urgency incontinence episodes/24 h. With regard to adverse events, tolterodine ER was associated with a good adverse event profile resulting in the third most favorable antimuscarinic. Antimuscarinic drugs are the mainstay of pharmacological therapy for OAB / storage LUTS; several studies have demonstrated that tolterodine ER is an effective and well tolerated formulation of this class of treatment.

Conclusion

Tolterodine ER resulted effective in reducing frequency urgency and nocturia and urinary leakage in male patients with OAB/storage LUTS. Dry mouth and constipation are the most frequently reported adverse events.

Characteristics of TRK-130 (Naltalimide), a novel opioid ligand, as a new therapeutic agent for overactive bladder

We characterized TRK-130 (N-[(5R,6R,14S)-17-(cyclopropylmethyl)-4,5-epoxy-3,14-dihydroxymorphinan-6-yl]phthalimide; naltalimide), an opioid ligand, to clarify the therapeutic potential for overactive bladder (OAB). In radioligand-binding assays with cells expressing human µ-opioid receptors (MORs), δ-opioid receptors (DORs), or κ-opioid receptors (KORs), TRK-130 showed high selectivity for MORs (Ki for MORs, DORs, and KORs = 0.268, 121, and 8.97 nM, respectively). In a functional assay (cAMP accumulation) with cells expressing each human opioid receptor subtype, TRK-130 showed potent but partial agonistic activity for MORs [EC50 (Emax) for MORs, DORs, and KORs = 2.39 nM (66.1%), 26.1 nM (71.0%), and 9.51 nM (62.6%), respectively]. In isovolumetric rhythmic bladder contractions (RBCs) in anesthetized guinea pigs, TRK-130 dose-dependently prolonged the shutdown time (the duration of complete cessation of the bladder contractions) (ED30 = 0.0034 mg/kg i.v.) without affecting amplitude of RBCs. Furthermore, TRK-130 ameliorated formalin-induced frequent urination at doses of higher than 0.01 mg/kg p.o. in guinea pigs under the freely moving condition. Meanwhile, TRK-130 showed only a negligible effect on the gastrointestinal transit at doses of up to 10 mg/kg s.c. in mice. These results indicate that TRK-130 is a potent and selective human MOR partial agonist without undesirable opioid adverse effects such as constipation and enhances the storage function by suppressing the afferent limb of the micturition reflex pathway, suggesting that TRK-130 would be a new therapeutic agent for OAB.

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.

Results of a randomized, double-blind, parallel-group, placebo- and active-controlled, multicenter study of mirabegron, a β3-adrenoceptor agonist, in patients with overactive bladder in Asia

AIMS

To assess the efficacy and safety of mirabegron 50 mg once daily compared with placebo and the active control, tolterodine extended-release (ER) 4 mg once daily, in patients with symptoms of overactive bladder (OAB) in Taiwan, Korea, China, and India.

METHODS

A 12-week multinational, randomized, double-blind, parallel-group placebo- and active-controlled trial. The primary efficacy endpoint was change from baseline to final visit in mean number of micturitions/24 hr. Secondary endpoints were: mean number of urgency episodes, incontinence episodes and urge incontinence episodes/24 hr, mean number of nocturia episodes per night, mean volume voided per micturition, and quality-of-life (QoL) scores as assessed by the King's Health Questionnaire (KHQ).

RESULTS

Of 1,126 patients who were randomized to receive double-blind study drug, 921 patients (300, 311, and 310 in the placebo, mirabegron 50 mg, and tolterodine ER 4 mg groups, respectively) completed the treatment period. Demographic characteristics were similar across treatment groups. A statistically significant improvement versus placebo in mean number of micturitions/24 hr was seen with mirabegron 50 mg at all timepoints (P < 0.05) as well as final visit (-0.57 with 95% confidence intervals [CIs] of [-1.04, -0.09], P = 0.019). There was no significant difference between treatment groups in improvement from baseline to final visit in any of the secondary outcome measures except volume voided per micturition. The overall incidence of drug-related adverse events was 17.2%, 15.8%, and 21.3%, in the placebo, mirabegron 50 mg, and tolterodine ER 4 mg groups, respectively.

CONCLUSIONS

Mirabegron 50 mg once daily for 12 weeks was superior to placebo in reducing the frequency of micturitions in patients with symptoms of OAB in Taiwan, Korea, China, and India.

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.

Efficacy of the β3-adrenoceptor agonist mirabegron for the treatment of overactive bladder by severity of incontinence at baseline: a post hoc analysis of pooled data from three randomised phase 3 trials

The β3-adrenoceptor agonist mirabegron is approved for treatment of the symptoms of overactive bladder (OAB). Incontinence can be the most bothersome of OAB symptoms. Hence, we conducted a post hoc analysis of pooled data from three randomised, double-blind, placebo-controlled, 12-wk, phase 3 studies of mirabegron to evaluate the efficacy of mirabegron 50mg in incontinent OAB patients and in subgroups of patients stratified by severity of incontinence at baseline (an average of two or more [FAS-I ≥ 2 subgroup] or four or more [FAS-I ≥ 4 subgroup] incontinence episodes per 24h at baseline, where FAS-I is the full analysis set-incontinence population) and to determine correlations between measures of efficacy and disease severity. Mirabegron 50mg resulted in statistically significant improvements from baseline to final visit versus placebo in mean number of incontinence episodes, micturitions, and urgency episodes per 24h and mean volume voided per micturition in the pooled incontinent population and in the FAS-I ≥ 2 and FAS-I ≥ 4 subgroups. Treatment effect versus placebo for incontinence and urgency episodes increased with increasing severity of incontinence at baseline. Moderate correlations were seen between improvement in both frequency of incontinence episodes and micturitions and baseline incontinence and micturition frequency, respectively, with mirabegron 50mg and placebo.

PATIENT SUMMARY

Incontinence can be the most bothersome of OAB symptoms; mirabegron 50mg once daily is effective for treatment of OAB symptoms in incontinent patients, and its effect increases with increasing severity of incontinence.

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.

Superiority of fesoterodine 8 mg vs 4 mg in reducing urgency urinary incontinence episodes in patients with overactive bladder: results of the randomised, double-blind, placebo-controlled EIGHT trial

OBJECTIVE

To assess the superiority of fesoterodine 8 mg vs 4 mg for improvement in urgency urinary incontinence (UUI) episodes and other diary variables, diary-dry rate (proportion of patients with >0 UUI episodes on baseline diary and 0 UUI episodes on post-baseline diary), and improvements in measures of symptom bother, health-related quality of life (HRQL), and other patient-reported outcomes (PROs).

PATIENTS AND METHODS

This was a 12-week, randomised, double-blind, placebo-controlled, multinational trial of men and women aged ≥18 years with overactive bladder (OAB) symptoms including UUI (ClinicalTrials.gov ID NCT01302067). Patients were randomised (2:2:1) to receive fesoterodine 8 mg, fesoterodine 4 mg, or placebo once daily; those randomised to fesoterodine 8 mg started with fesoterodine 4 mg once daily for 1 week, then 8 mg once daily for the remaining 11 weeks. Patients completed bladder diaries at baseline and weeks 4 and 12 and the Patient Perception of Bladder Condition (PPBC), Urgency Perception Scale (UPS), and Overactive Bladder Questionnaire (OAB-q) at baseline and week 12. The primary endpoint was change from baseline to week 12 in UUI episodes per 24 h.

RESULTS

At week 12, patients receiving fesoterodine 8 mg (779 patients) had significantly greater reductions from baseline in UUI episodes, micturitions, and urgency episodes than patients receiving fesoterodine 4 mg (790) or placebo (386); diary-dry rate was significantly higher in the fesoterodine 8-mg group vs the fesoterodine 4-mg and placebo groups (all P < 0.05). At week 12, patients receiving fesoterodine 8 mg also had significantly greater improvements in scores on the PPBC, UPS, and all OAB-q scales and domains than patients receiving fesoterodine 4 mg or placebo (all P < 0.01). Patients receiving fesoterodine 4 mg had significantly greater improvements in UUI episodes, urgency episodes, and micturitions; significantly higher diary-dry rates; and significantly greater improvement in PPBC scores and OAB-q scores than patients receiving placebo (all P < 0.05). Dry mouth was the most commonly reported adverse event (AE) in the fesoterodine groups (placebo group, 3.4%; fesoterodine 4-mg group, 12.9%; fesoterodine 8-mg group, 26.1%); most cases were mild or moderate in all treatment groups. Rates of serious AEs and discontinuations due to AEs were low in all groups.

CONCLUSIONS

In a 12-week, prospectively designed, superiority trial, fesoterodine 8 mg showed statistically significantly superior efficacy vs fesoterodine 4 mg and placebo, as measured by reductions in UUI episodes and other diary variables, diary-dry dry rate, and improvements in measures of symptom bother, HRQL, and other PROs; clear evidence of dose-dependent efficacy is unique to fesoterodine among antimuscarinics and other oral agents for the treatment of OAB. Fesoterodine 4 mg was significantly more effective than placebo on all outcomes except for improvements in UPS scores. These data support the benefit of having two doses of fesoterodine in clinical practice, with the recommended starting dose of 4 mg for all patients and the fesoterodine 8-mg dose available for patients who require a higher dose to achieve optimal symptom relief.

Expert consensus on scientific evidence available on the use of botulinum toxin in overactive bladder

OBJECTIVES

Overactive bladder (OAB) is a pathology impairing patients' quality of life and with a high percentage of patients who are refractory to medication. In this paper, technical opinion of an «expert panel» is assessed in order to gain the most reliable professional consensus on scientific evidence available on the criteria of use of Onabotulinumtoxin A (OnabotA) in OAB.

MATERIAL AND METHODS

according to DELPHI method, 42 panelists answered a survey of 93 items divided into four strategic areas including clinical criteria and recommendations in order to improve, at different levels, the current approach to patients with OAB. The recent advances in the field, areas of controversy and their real application possibilities in the different areas of our health care system were taken into consideration.

RESULTS

Two rounds of the questionnaire were completed by all experts. In the first round, a criteria consensus was reached for 64 of 93 (68.8%) questions analyzed; in the second round the consensus reached was for 83 items evaluated (89.25%). An agreement among panelist was reached for: 1) definition, classification, detection and differential diagnosis; 2) medical treatment; 3) surgical treatment; 4) role of OnabotA in the treatment of OAB.

CONCLUSIONS

the consensus is broadly in line with the latest scientific evidence on OAB. The panelists believe that it is necessary to propose a change in the current definition of OAB and that it seems necessary to improve the screening tools too. Medical treatment of OAB must be tailored to each patient, staged and progressive. The use of OnabotA (Botox(®)) could imply therapeutic advantages with respect to other treatments, and positions itself as a safe and effective alternative to treat drug refractory OAB.

Defining response and non-response to treatment in patients with overactive bladder: a systematic review

OBJECTIVE

There is currently a lack of formal guidance for assessing treatment response and non-response in patients with overactive bladder (OAB). Such guidance would be useful for both clinical practice and the design of clinical trials. Our purpose was to review and assess definitions of treatment response and non-response used in patients with OAB.

METHODS

We conducted a systematic review of articles published between January 1, 2005 and August 8, 2013 using PubMed. Search terms included (overactive bladder) AND ('treatment response' OR responder OR success OR satisfied OR goal OR refractory OR nonresponder OR fail OR persistent OR dissatisfied). Limits were 'humans' and 'English'. Studies conducted in subjects with neurogenic detrusor overactivity, conditions other than OAB, or OAB symptoms following lower urinary tract/pelvic surgery were excluded; case reports and letters were also excluded.

RESULTS

The literature search returned 423 articles, of which 75 met the inclusion criteria and defined a specific threshold by which treatment response or non-response was determined for patients receiving behavioral therapy and/or treatment with an antimuscarinic, β3-agonist, botulinum toxin, or neural stimulation. One published abstract from congress proceedings and three additional articles that were not identified by the search were included; thus, a total of 79 records were included. A wide variety of symptom-based definitions and patient-reported outcomes (PROs) were used. Symptom-based definitions frequently used a threshold of 50-100% improvement in general or specific symptoms; urgency urinary incontinence (UUI) was often used in studies with incontinent patients. Definitions based on PROs frequently used measures of satisfaction, general improvement, or goal achievement. Studies of patients with refractory OAB often referred to a failure to respond to ≥1 other therapy, or to poor efficacy or unacceptable tolerability, without further specification. Limitations of this review are that only English language articles were included and that only the PubMed database was used for the literature search.

CONCLUSIONS

There is considerable heterogeneity in the definitions of treatment response and non-response in trials of patients with OAB; some standardization would be beneficial. However, there is also heterogeneity among patients of what constitutes treatment success or failure, and conceptualizations of treatment response and non-response in both clinical trials and clinical practice must take patient characteristics into account. For patients with UUI, it is recommended that the criteria for treatment response include this symptom, as measured by change in the absolute number of UUI episodes or achievement of continence, given its impact on patients' lives and associated bother. PROs provide important information that confirm symptom-based measures by demonstrating that observed changes in symptoms are meaningful to the patient. In clinical practice, measures of treatment satisfaction and goal achievement can be highly useful.

Discovery history and clinical development of mirabegron for the treatment of overactive bladder and urinary incontinence

INTRODUCTION

Overactive bladder (OAB) and urinary incontinence, although not life-threatening, are very bothersome chronic health conditions. The limitations of current pharmacological treatment urge the need for novel drugs with alternative mechanisms of action. Huge efforts in this area of research led to the synthesis of several selective and potent β3-adrenoceptor agonists that gained relevance through research during the late 80s and 90s. Mirabegron was the first compound of this new class of drugs that showed preclinical efficacy in several models of storage bladder dysfunction, together with a favorable human pharmacological profile. Having passed the proof-of-concept stage, an extensive clinical development and pharmacology program was performed during the last 10 years, involving >10,000 individuals, before mirabegron was granted marketing approval.

AREAS COVERED

In this case history, the authors review the milestones in mirabegron's discovery based on a systematic literature review.

EXPERT OPINION

Thanks to its tolerability and safety/efficacy balance, mirabegron has potential to fill a need for new treatment options for OAB, and paves the way for further development of a completely new class of drugs aimed to treat this condition. However, the exact role of mirabegron in clinical practice has yet to be defined. Further studies are needed in order to clarify, together with post-launch information, critical safety issues and cost-effectiveness in head-to-head comparison with current standard treatments.

Pharmacotherapy of overactive bladder in adults: a review of efficacy, tolerability, and quality of life

Introduction

Overactive bladder (OAB) is a prevalent condition that has a significant impact on quality of life. The usual treatment approach is both behavioral and pharmacological. The first-line pharmacological treatment commonly utilizes anticholinergic agents, which may be limited by their tolerability, efficacy, and long-term compliance. Developments in elucidating the pathophysiology of OAB and alternative targets for pharmacological therapy have led to newer agents being developed to manage this condition. These agents include mirabegron and botulinum toxin, which have alternate mechanism of action and avoid the anticholinergic side effects.

Objectives

To provide an update for clinicians managing OAB with an overview of the existing and newer medical options for OAB, including pharmacology, efficacy, side-effect profile, tolerability, and impact on patient quality of life.

Methods

PubMed and Medline were searched for randomized controlled drug trials in adults with OAB, meta-analyses of medical therapy for OAB, and individual drug names, including the keywords efficacy, tolerability, quality of life, and compliance. Nonhuman studies, pediatric trials, and those involving patients with neurogenic bladder dysfunction (with the exception of studies involving botulinum toxin A) were excluded.

Results

There is level 1, Grade A evidence to support the efficacy of anticholinergic drugs, botulinum toxin, and mirabegron for OAB. Long-term compliance with anticholinergic medications is limited. The mechanism of action, effectiveness, and side effects of these drugs are discussed, and where the data are available compared with other OAB medications.

Conclusion

Most of the anticholinergic agents have comparative efficacies and core side-effect profiles, with individual variations relating to their muscarinic receptor selectivity, pharmacokinetics, and metabolism. Newer agents, with alternative sites of action, such as mirabegron and botulinum toxin, provide additional treatment options for patients intolerant to or inadequately treated with anticholinergics.