Mirabegron in overactive bladder: a review of efficacy, safety, and tolerability

Diaryl pyrrolone fluorescent probing strategy for Mirabegron determination through condensation with ninhydrin and phenylacetaldehyde: Application to dosage forms, human urine and plasma

Mirabegron (MRB) is a β3-adrenoceptor agonist used for managing overactive bladder syndrome. A cost-effective, environmentally friendly, and highly sensitive spectrofluorimetric method was suggested to serve the purpose of quantifying MRB in its pure state, pharmaceutical tablets, spiked human plasma and urine, and testing content uniformity. In the present study, ninhydrin and phenylacetaldehyde react with the amino group moiety of MRB in Teorell-Stenhagen buffer (pH 7.5) to generate a strongly fluorescent diaryl pyrrolone compound that emits fluorescence at a wavelength of 477 nm upon excitation at 385 nm. The obtained calibration curve showed a linear relationship with a high correlation coefficient (r = 0.9997) in the concentration range of 0.25 to 5.0 µg mL-1. Limits of detection (LOD) and quantitation (LOQ) were 0.082 and 0.248 µg mL-1 respectively. The procedure was verified in accordance with the ICH guidelines. The suggested approach could be utilized for the selective analysis of MRB in its pharmaceuticals, either containing a single drug or co-formulated with solifenacin succinate. The greenness of the suggested method was confirmed using different green analytical metrics.

Mirabegron Versus Placebo and Other Therapeutic Modalities in the Treatment of Patients with Overactive Bladder Syndrome-A Systematic Review

BACKGROUND AND OBJECTIVE

The prevalence of overactive bladder (OAB) increases with age. Mirabegron and other drugs are used for the management of patients with OAB. To evaluate mirabegron versus other treatments for overactive bladder syndrome (OAB).

METHODS

This randomised controlled trial (RCT)-based systematic review (CRD42020200394) was conducted following the 2020 Preferred Reporting Items for Systematic Reviews and Meta-analyses statement, with standards reported in the Cochrane Handbook for Systematic Reviews of Interventions.

KEY FINDINGS AND LIMITATIONS

We included 28 RCTs (n = 27 481 adults), comparing the following: mirabegron 25 mg versus placebo (n = 8798; six RCTs): significant changes in urgency urinary incontinence (mean difference [MD] -0.41, 95% confidence interval [CI] -0.56 to -0.26), total incontinence (MD -0.47, 95% CI -0.63 to -0.30), and nocturia (MD -0.10, 95% CI -0.17 to -0.02), and mirabegron 50 mg versus placebo (n = 14 933; 12 RCTs): significant changes in urgency urinary incontinence (MD -0.41, 95% CI -0.52 to -0.31), urgency (MD -0.49, 95% CI -0.64 to -0.33), total incontinence (MD -0.44, 95% CI -0.55 to -0.33), favouring mirabegron 25/50 mg; mirabegron 50 mg versus tolterodine 4 mg (n = 8008; five RCTs): significant changes in micturition (MD -0.16, 95% CI -0.31 to -0.02) and overall adverse events (AEs; odds ratio [OR] 0.71, 95% CI 0.59-0.86), favouring mirabegron 50 mg; mirabegron 50 mg versus solifenacin 5 mg (n = 8911; four RCTs): significant changes in voided volume/micturition in millilitres (MD -7.77, 95% CI -12.93 to -2.61), favouring mirabegron 50 mg; and mirabegron 50 mg versus oxybutynin 73.5 mg (n = 302; one RCT): significant changes in overall AEs (OR 0.02, 95% CI 0.00-0.16), favouring mirabegron 50 mg.

CONCLUSIONS AND CLINICAL IMPLICATIONS

Mirabegron is effective, safe, and well tolerated. Coadministration with anticholinergics provides an advantageous additive effect without a higher occurrence of side effects.

PATIENT SUMMARY

Mirabegron is effective, safe, and well tolerated for treating overactive bladder. When used in conjunction with anticholinergic medications, it provides extra benefits without causing more side effects.

Prevalence and risk factors for overactive bladder symptoms in patients with artificial urinary sphincter

To demonstrate the prevalence and risk factors for overactive bladder symptoms associated with artificial urinary sphincter implantation, we investigated the patients who underwent primary artificial urinary sphincter implantation with severe urinary stress incontinence. Forty-eight patients who completely answered the questionnaires of the overactive bladder symptom score before surgery were included. Patient characteristics, urinary status at pre and 1, 3, 6, and 12 months post-device activation, and predictive factors for overactive bladder symptoms were examined. Sixty percent of the patients had preoperative overactive bladder symptoms. Until 12 months after device activation, 35-40% of all patients had overactive bladder symptoms. The rate of persistent and de novo postoperative overactive bladder symptoms was 44.8% and 26.3%, respectively. Daily pad use was not different between patients w/wo overactive bladder symptoms. The only risk factor for postoperative overactive bladder symptoms was a max cystometoric capacity < 200 mL measured by a preoperative urodynamic study. Attention must be given to both persistent and de novo overactive bladder symptoms associated with artificial urinary sphincter implantation for patients with stress incontinence. Counsel should equally be provided for preoperative overactive bladder symptoms, especially in cases with a cystometric capacity < 200 mL.

Physiological and metabolic functions of the β3-adrenergic receptor and an approach to therapeutic achievements

A specific type of beta-adrenergic receptor was discovered in the decade of 1980s and subsequently recognized as a new type of beta-adrenergic receptor, called beta3-adrenoceptor (β3-AR). β3-AR expresses in different tissues, including adipose tissue, gall bladder, stomach, small intestine, cardiac myocytes, urinary bladder, and brain. Structurally, β3-AR is very similar to β1- and β2-AR and belongs to a G-protein coupled receptor that uses cAMP as an intracellular second messenger. Alternatively, it also activates the NO-cGMP cascade. Stimulation of the β3-AR increases lipolysis, fatty acid oxidation, energy expenditure, and insulin action, leading to anti-obesity and anti-diabetic activity. Moreover, β3-AR differentially regulates the myocardial contraction and relaxes the urinary bladder to balance the cardiac activity and delay the micturition reflex, respectively. In recent years, this receptor has served as an attractive target for the treatment of obesity, type 2 diabetes, congestive heart failure, and overactive bladder syndrome. Several β3-AR agonists are in the emerging stage that can exert novel pharmacological benefits in different therapeutic areas. The present review focuses on the structure, signaling, physiological, and metabolic activities of β3-AR. Additionally, therapeutic approaches of β3-AR have also been considered.

Risk factors associated with the severity of overactive bladder among Syrian patients with type 2 diabetes

The prevalence of overactive bladder (OAB) is known to be higher in patients with type 2 diabetes (T2DM). However, few studies have examined specific risk factors contributing to its progression among diabetes mellitus (DM) patients, so this study aimed to investigate the risk factors specific to diabetes mellitus that influence overactive bladder in the Syrian population. This cross-sectional study was conducted at four endocrinology centers in four Syrian provinces: Damascus, Aleppo, Homs, Hama, and Latakia. The study was comprised of patients who had been diagnosed with both T2DM and OAB and had visited these centers from February 2020 to January 2023. The Arabic version of the Overactive Bladder Symptom Score (OABSS) scale was used to categorize the participants based on the severity score into two groups: the mild OAB group and the moderate-severe OAB group. A logistic analysis was conducted to assess the risk factors associated with the OAB among patients with diabetes. Among the 153 patients diagnosed with both DM and OAB, significant distinctions were found between the two groups concerning the severity of overactive bladder, age, duration of diabetes, symptomatic diabetic peripheral neuropathy (DPN), and ankle reflex (P < 0.05). Furthermore, a multivariate analysis revealed that age (OR 1.48, 95% CI 0.89-2.19), duration of diabetes (OR 1.94, 95% CI 0.53-2.23), and symptomatic DPN (OR 2.74, 95% CI 1.39-4.13) independently acted as risk factors for the advancement of OAB. The severity of OAB in Syrian patients with diabetes is closely associated with the severity of DM. Factors such as age, duration of diabetes, and symptomatic DPN are independent predictors of the severity of OAB. Patients who experience symptomatic DPN are at an increased risk of developing OAB.

Ligand-Receptor Interactions and Structure-Function Relationships in Off-Target Binding of the β3-Adrenergic Agonist Mirabegron to α1A-Adrenergic Receptors

The β3-adrenoceptor agonist mirabegron is available for the treatment of storage symptoms of overactive bladder, including frequency, urgency, and incontinence. The off-target effects of mirabegron include binding to α1-adrenoceptors, which are central in the treatment of voiding symptoms. Here, we examined the structure-function relationships in the binding of mirabegron to a cryo-electron microscopy structure of α1A. The binding was simulated by docking mirabegron to a 3D structure of a human α1A-adrenoceptor (7YMH) using Autodock Vina. The simulations identified two binding states: slope orientation involving 10 positions and horizontal binding to the receptor surface involving 4 positions. No interactions occurred with positions constituting the α1A binding pocket, including Asp-106, Ser-188, or Phe-312, despite the positioning of the phenylethanolamine moiety in transmembrane regions close to the binding pocket by contact with Phe-288, -289, and Val-107. Contact with the unique positions of α1A included the transmembrane Met-292 during slope binding and exosite Phe-86 during horizontal binding. Exosite binding in slope orientation involved contact of the anilino part, rather than the aminothiazol end, to Ile-178, Ala-103, and Asn-179. In conclusion, contact with Met-292 and Phe-86, which are unique positions of α1A, accounts for mirabegron binding to α1A. Because of its lack of interactions with the binding pocket, mirabegron has lower affinity compared to α1A-blockers and no effects on voiding symptoms.

Role of cAMP/pCREB and GSK-3β/NF-κB p65 signaling pathways in the renoprotective effect of mirabegron against renal ischemia-reperfusion injury in rats

Acute kidney injury and other renal disorders are thought to be primarily caused by renal ischemia-reperfusion (RIR). Cyclic adenosine monophosphate (cAMP) has plenty of physiological pleiotropic effects and preserves tissue integrity and functions. This research aimed to examine the potential protective effects of the β3-adrenergic receptors agonist mirabegron in a rat model of RIR and its underlying mechanisms. Male rats enrolled in this work were given an oral dose of 30 mg/kg mirabegron for two days before surgical induction of RIR. Renal levels of kidney injury molecule-1 (KIM-1), monocyte chemoattractant protein-1 (MCP-1), tumor necrosis factor-alpha (TNF-α), Interleukin-10 (IL-10), cAMP, cAMP-responsive element binding protein (pCREB), and glycogen synthase kinase-3 beta (GSK-3β) were assessed along with blood urea nitrogen and serum creatinine. Additionally, caspase-3 and nuclear factor-kappa B (NF-κB) p65 were explored by immunohistochemical analysis. Renal specimens were inspected for histopathological changes. RIR led to renal tissue damage with elevated blood urea nitrogen and serum creatinine levels. The renal KIM-1, MCP-1, TNF-α, and GSK-3β were significantly increased, while IL-10, cAMP, and pCREB levels were reduced. Moreover, upregulation of caspase-3 and NF-κB p65 protein expression was seen in RIR rats. Mirabegron significantly reduced kidney dysfunction, histological abnormalities, inflammation, and apoptosis in the rat renal tissues. Mechanistically, mirabegron mediated these effects via modulation of cAMP/pCREB and GSK-3β/NF-κB p65 signaling pathways. Mirabegron administration could protect renal tissue and maintain renal function against RIR.

Safety and efficacy of beta-3 adrenergic agonists in treating neurogenic lower urinary tract dysfunction: A systematic review and meta-analysis

PURPOSE

To evaluate efficacy and safety of beta-3 adrenergic agonists in adults with neurogenic lower urinary tract dysfunction.

MATERIALS AND METHODS

According to a protocol (CRD42022350079), we searched multiple data sources for published and unpublished randomized controlled trials (RCTs) up to 2nd August 2022. Two review authors independently screened studies and abstracted data from the included studies. We performed statistical analyses by using a random-effects model and interpreted them according to the Cochrane Handbook for Systematic Reviews of Interventions. We used GRADE guidance to rate the certainty of evidence (CoE).

RESULTS

We found data to inform two comparisons: beta-3 adrenergic agonists versus placebo (4 RCTs) and anticholinergics (2 RCTs). Only mirabegron was used for intervention in all included studies. Compared to placebo, beta-3 adrenergic agonists may have a clinically unimportant effect on urinary symptoms score (mean difference [MD] -2.50, 95% confidence interval [CI] -4.78 to -0.22; I²=92%; 2 RCTs; 192 participants; low CoE) based on minimal clinically important difference of 3. We are very uncertain of the effects of beta-3 adrenergic agonists on quality of life (MD 10.86, 95% CI 1.21 to 20.50; I²=41%; 2 RCTs; 98 participants; very low CoE). Beta-3 adrenergic agonists may result in little to no difference in major adverse events (cardiovascular adverse events) (risk ratio 0.57, 95% CI 0.14 to 2.37; I²=0%; 4 RCTs; 310 participants; low CoE). Compared to anticholinergics, no study reported urinary symptom scores and quality of life. There were no major adverse events (cardiovascular adverse events) in either study group (1 study; 60 participants; very low CoE).

CONCLUSIONS

Compared to placebo, beta-3 adrenergic agonists may have similar effects on urinary symptom scores and major adverse events. There were uncertainties about their effects on quality of life. Compared to anticholinergics, we are either very uncertain or have no evidence about urinary symptom scores, quality of life, and major adverse events.

The β3-AR agonist BRL37344 ameliorates the main symptoms of X-linked nephrogenic diabetes insipidus in the mouse model of the disease

X-linked nephrogenic diabetes insipidus (X-NDI) is a rare congenital disease caused by inactivating mutations of the vasopressin type-2 receptor (AVPR2), characterized by impaired renal concentrating ability, dramatic polyuria, polydipsia and risk of dehydration. The disease, which still lacks a cure, could benefit from the pharmacologic stimulation of other GPCRs, activating the cAMP-intracellular pathway in the kidney cells expressing the AVPR2. On the basis of our previous studies, we here hypothesized that the β3-adrenergic receptor could be such an ideal candidate. We evaluated the effect of continuous 24 h stimulation of the β3-AR with the agonist BRL37344 and assessed the effects on urine output, urine osmolarity, water intake and the abundance and activation of the key renal water and electrolyte transporters, in the mouse model of X-NDI. Here we demonstrate that the β3-AR agonism exhibits a potent antidiuretic effect. The strong improvement in symptoms of X-NDI produced by a single i.p. injection of BRL37344 (1 mg/kg) was limited to 3 h but repeated administrations in the 24 h, mimicking the effect of a slow-release preparation, promoted a sustained antidiuretic effect, reducing the 24 h urine output by 27%, increasing urine osmolarity by 25% and reducing the water intake by 20%. At the molecular level, we show that BRL37344 acted by increasing the phosphorylation of NKCC2, NCC and AQP2 in the renal cell membrane, thereby increasing electrolytes and water reabsorption in the kidney tubule of X-NDI mice. Taken together, these data suggest that human β3-AR agonists might represent an effective possible treatment strategy for X-NDI.

Effect of Mirabegron in Men With Overactive Bladder and Erectile Dysfunction: A Prospective Observational Study

BACKGROUND

As it has been observed that the erect penis has been the epitome of virility for the male community for decades, it became necessary to search for alternative treatments for the cause. So, the study was performed to evaluate the potential impact of mirabegron in men with mild to moderate erectile dysfunction (ED) and overactive bladder (OAB).

METHODS

It was a prospective, observational study that was carried out at the Department of Urology at Rajendra Institute of Medical Sciences, Ranchi, for a duration of two years and included a total of two hundred fifty patients. The individuals included had a diagnosis of mild to moderate erectile dysfunction (ED) along with symptoms of OAB. The overactive bladder questionnaire (OAB-q) score and the International Index of Erectile Dysfunction-5 (IIEF-5) score were used, respectively, to measure the impact of mirabegron on ED and OAB. Then, the changes in ED and OAB were evaluated at two, four, eight, and 12 weeks.

RESULTS

Among the total 250 patients recruited, around 32.5% of them had mild ED, 17.5% were diagnosed with mild to moderate ED, and 50% suffered from moderate ED. The IIEF-5 scores improved by four points or more in 86.25%, 91.25%, and 71.25% of patients after four, eight, and 12 weeks, respectively. OAB-q scores were likewise shown to decline in the fourth (13.1 ± 4.3) and eighth (12.8 ± 4.2) weeks when compared to the baseline (17.4 ± 5.5). Also, adverse events reported did not hamper the progress of the study.

CONCLUSION

The study concluded that mirabegron has a beneficial impact on controlling OAB symptoms among men diagnosed with mild to moderate ED. The effects last for only eight weeks, and then they decline. Furthermore, mirabegron was well-tolerated among patients and had no safety concerns with its use.

Age-dependent effects of the β3 adrenoceptor agonist CL316,243 on human and rat detrusor muscle strips

Motility of detrusor smooth muscle includes adrenergic relaxation and cholinergic contraction. Since the latter may be deregulated in overactive bladder (OAB) pathophysiology, anticholinergics are the standard therapy but occasionally less tolerated due to side effects such as dry mouth and constipation. β3 adrenoceptor agonists also alleviate OAB symptoms by relaxing the detrusor muscle. Their age dependence, however, is far from understood. To address this issue, we induced contractions with KCl (60 mM) and carbachol (from 10 nM to 100 μM) in the presence of the β3 adrenoceptor agonist CL316,243 (from 0.1 to 10 μM) in both human and rat muscle strips. Our results confirmed that both contractions were attenuated by β3 adrenoceptor activation in both species, but with differing age dependence. In humans, specimens from mid-life subjects showed a significantly more pronounced effect of CL316,243 in attenuating carbachol-induced contractions than those from aged subjects (Cohen's d of maximal attenuation: 1.82 in mid-life versus 0.13 in aged) without altering EC50. Conversely, attenuation of KCl responses by CL316,243 increased during ageing (Spearman correlation coefficient = -0.584, P<0.01). In rats, both KCl- and carbachol-induced contractions were significantly more attenuated by CL316,243 in samples from adolescent as compared to aged samples. Immunohistochemistry in human detrusor sections proved β3 adrenoreceptor abundance to remain unaltered during ageing. In conclusion, our findings suggest differential age-dependent changes in human β3 adrenoceptor-dependent attenuation of detrusor contraction in terms of electromechanical versus pharmacomechanical coupling; they may help understand the differential responsiveness of OAB patients to β3 agents.

Inside the Biology of the β3-Adrenoceptor

Since the first discovery in 1989, the β3-adrenoceptor (β3-AR) has gained great attention because it showed the ability to regulate many physiologic and metabolic activities, such as thermogenesis and lipolysis in brown and white adipose tissue, respectively (BAT, WAT), negative inotropic effects in cardiomyocytes, and relaxation of the blood vessels and the urinary bladder. The β3-AR has been suggested as a potential target for cancer treatment, both in adult and pediatric tumors, since under hypoxia its upregulation in the tumor microenvironment (TME) regulates stromal cell differentiation, tumor growth and metastases, signifying that its agonism/antagonism could be useful for clinical benefits. Promising results in cancer research have proposed the β3-AR being targeted for the treatment of many conditions, with some drugs, at present, undergoing phase II and III clinical trials. In this review, we report the scientific journey followed by the research from the β3-Ars' discovery, with focus on the β3-Ars' role in cancer initiation and progression that elects it an intriguing target for novel antineoplastic approaches. The overview highlights the great potential of the β3-AR, both in physiologic and pathologic conditions, with the intention to display the possible benefits of β3-AR modulation in cancer reality.

Adrenoceptors in the Lower Urinary Tract

Adrenoceptors importantly contribute to the physiological regulation of lower urinary tract (LUT) function and have become a target of several clinically successful treatments for major LUT diseases. In the bladder dome, β-adrenoceptor subtypes are found in multiple cell types and mediate relaxation of detrusor smooth muscle, perhaps partly indirectly by acting on afferent nerves and cells of the mucosa. β3-adrenoceptor agonists such as mirabegron and vibegron are used to treat overactive bladder syndrome. In the bladder trigone and urethra, α1-adrenoceptors cause contraction and thereby physiologically contribute to bladder outlet resistance. α1-adrenoceptors in the prostate also cause contraction and pathophysiologically elevate bladder outlet resistance leading to voiding dysfunction in benign prostatic hyperplasia. α1-adrenoceptor antagonist such as tamsulosin is widely used as a first-line option to treat LUT symptoms in men, but it remains unclear to which extent and how smooth muscle relaxation contributes to symptom relief.

Is the β3-Adrenoceptor a Valid Target for the Treatment of Obesity and/or Type 2 Diabetes?

β3-Adrenoceptors mediate several functions in rodents that could be beneficial for the treatment of obesity and type 2 diabetes. This includes promotion of insulin release from the pancreas, cellular glucose uptake, lipolysis, and thermogenesis in brown adipose tissue. In combination, they lead to a reduction of body weight in several rodent models including ob/ob mice and Zucker diabetic fatty rats. These findings stimulated drug development programs in various pharmaceutical companies, and at least nine β3-adrenoceptor agonists have been tested in clinical trials. However, all of these projects were discontinued due to the lack of clinically relevant changes in body weight. Following a concise historical account of discoveries leading to such drug development programs we discuss species differences that explain why β3-adrenoceptors are not a meaningful drug target for the treatment of obesity and type 2 diabetes in humans.

Repurposing the β3-Adrenergic Receptor Agonist Mirabegron in Patients With Structural Cardiac Disease: The Beta3-LVH Phase 2b Randomized Clinical Trial

Importance

Left ventricular (LV) hypertrophy contributes to the onset and progression of heart failure (HF), particularly for patients with pre-HF (stage B) for whom no treatment has yet proven effective to prevent transition to overt HF (stage C). The β3-adrenergic receptors (β3ARs) may represent a new target, as their activation attenuates LV remodeling.

Objective

To determine whether activation of β3ARs by repurposing a β3AR agonist, mirabegron, is safe and effective in preventing progression of LV hypertrophy and diastolic dysfunction among patients with pre- or mild HF.

Design, Setting, and Participants

The Beta3-LVH prospective, triple-blind, placebo-controlled phase 2b randomized clinical trial enrolled patients between September 12, 2016, and February 26, 2021, with a follow-up of 12 months. The trial was conducted at 10 academic hospitals in 8 countries across Europe (Germany, Poland, France, Belgium, Italy, Portugal, Greece, and the UK). Patients aged 18 years or older with or without HF symptoms (maximum New York Heart Association class II) were screened for the presence of LV hypertrophy (increased LV mass index [LVMI] of ≥95 g/m2 for women or ≥115 g/m2 for men) or maximum wall thickness of 13 mm or greater using echocardiography. Data analysis was performed in August 2022.

Intervention

Participants were randomly assigned (1:1) to mirabegron (50 mg/d) or placebo, stratified by the presence of atrial fibrillation and/or type 2 diabetes, for 12 months.

Main Outcomes and Measures

The primary end points were LVMI determined using cardiac magnetic resonance imaging and LV diastolic function (early diastolic tissue Doppler velocity [E/e'] ratio assessed using Doppler echocardiography) at 12 months. Patients with at least 1 valid measurement of either primary end point were included in the primary analysis. Safety was assessed for all patients who received at least 1 dose of study medication.

Results

Of the 380 patients screened, 296 were enrolled in the trial. There were 147 patients randomized to mirabegron (116 men [79%]; mean [SD] age, 64.0 [10.2] years) and 149 to placebo (112 men [75%]; mean [SD] age, 62.2 [10.9] years). All patients were included in the primary intention-to-treat analysis. At 12 months, the baseline and covariate-adjusted differences between groups included a 1.3-g/m2 increase in LVMI (95% CI, -0.15 to 2.74; P = .08) and a -0.15 decrease in E/e' (95% CI, -0.69 to 0.4; P = .60). A total of 213 adverse events (AEs) occurred in 82 mirabegron-treated patients (including 31 serious AEs in 19 patients) and 215 AEs occurred in 88 placebo-treated patients (including 30 serious AEs in 22 patients). No deaths occurred during the trial.

Conclusions

In this study, mirabegron therapy had a neutral effect on LV mass or diastolic function over 12 months among patients who had structural heart disease with no or mild HF symptoms.

Trial Registration

ClinicalTrials.gov Identifier: NCT02599480.

Comparison of Efficacy and Safety of a Combination of Tamsulosin and Mirabegron versus Tamsulosin Alone in the Management of Overactive Bladder in Males with Lower Urinary Tract Symptoms - TAME-Overactive Bladder: An Open-labeled Randomized Controlled Trial

Background

Overactive bladder (OAB) is a common condition in elderly men with coexisting benign prostatic enlargement (BPE), and it significantly impairs their quality of life (QoL).

Aim

This study aimed to assess the safety and efficacy of adding beta-3 adrenergic receptor agonist (mirabegron 50 mg) to tamsulosin 0.4 mg for symptomatic men with BPE and OAB symptoms (OABS).

Materials and Methods

It was an open-labeled randomized controlled trial. Ninety men with BPE and International Prostate Symptom Score (IPSS) of more than seven with predominant OABS were enrolled for the study. A detailed history, uroflowmetry, and baseline scores, including IPSS, OABS score (OABSS), and QoL assessment, were done for each patient. After written informed consent, patients were randomized into two groups of 45 each. Group-1 received tamsulosin 0.4 mg and placebo, and Group-2 received a combination of tamsulosin 0.4 mg plus mirabegron 50 mg once daily at bedtime. Follow-up of patients was done at 2nd, 4th, and 8th weeks. Efficacy at 8 weeks was assessed using repeat history for symptoms, uroflowmetry, IPSS, OABSS, and QoL score.

Results

After 8 weeks of therapy, collected data were compared to baseline parameters in both groups. Significant improvement with respect to OABSS (P = 0.046), IPSS (P = 0.006), and QoL (P = 0.038) was observed with combination therapy versus tamsulosin alone. There were mild adverse effects, which were self-limiting.

Conclusions

A combination of tamsulosin with mirabegron is effective and safe in improving the OABSS, IPSS, and QoL in men with BPE who have predominant OABS.

Persistence of overactive bladder pharmacological treatment in women as reflected from large-scale real-world data of prescription claims: A retrospective cohort study

INTRODUCTION AND OBJECTIVES

Medical treatments for overactive bladder (OAB) have proven efficacy in controlled trials. However, 1-year treatment persistence is reported to be as low as 25% for anticholinergics and 40% for β3 agonists. Real-world data on treatment continuation and treatment sequence is limited. Therefore, we aimed to study treatment persistence trends in women initiated on OAB medications.

MATERIALS AND METHODS

We used advanced data-mining techniques to query the largest regional provider's medication purchase database, dispensing for patients, for all women initiating OAB pharmacotherapy between 2010 and 2020. Treatment persistence was measured as days in which the patient was in possession of medication and nonpersistence was defined as prescription nonrefilling for 90 days. We employed a Sankey diagram to explore trends in OAB medication acquisition and treatment sequence. We compared treatment persistence using Kaplan-Meier survival curves and pairwise log-rank analysis.

RESULTS

Here, 46 079 women made 791 681 unique claims of OAB medications. Only 39% of the patients tried more than one OAB formulation, including dose change. The overall persistence rate for all drugs was 55% in 30 days, 46% in 90 days, and 37% per year. The persistence rate for Mirabegron at 30 days was 54%, 42% at 90 days, and 17% at 1 year. Overall, persistence rates were unchanged when stratifying by the time Mirabegron insurance acceptance into coverage (p > 0.05).

CONCLUSIONS

Real-world OAB pharmacotherapy persistence rates are lower than previously reported. The introduction of Mirabegron did not seem to improve these rates or affect the treatment sequence.

New Therapeutics for Heart Failure: Focusing on cGMP Signaling

Current drugs for treating heart failure (HF), for example, angiotensin II receptor blockers and β-blockers, possess specific target molecules involved in the regulation of the cardiac circulatory system. However, most clinically approved drugs are effective in the treatment of HF with reduced ejection fraction (HFrEF). Novel drug classes, including angiotensin receptor blocker/neprilysin inhibitor (ARNI), sodium-glucose co-transporter-2 (SGLT2) inhibitor, hyperpolarization-activated cyclic nucleotide-gated (HCN) channel blocker, soluble guanylyl cyclase (sGC) stimulator/activator, and cardiac myosin activator, have recently been introduced for HF intervention based on their proposed novel mechanisms. SGLT2 inhibitors have been shown to be effective not only for HFrEF but also for HF with preserved ejection fraction (HFpEF). In the myocardium, excess cyclic adenosine monophosphate (cAMP) stimulation has detrimental effects on HFrEF, whereas cyclic guanosine monophosphate (cGMP) signaling inhibits cAMP-mediated responses. Thus, molecules participating in cGMP signaling are promising targets of novel drugs for HF. In this review, we summarize molecular pathways of cGMP signaling and clinical trials of emerging drug classes targeting cGMP signaling in the treatment of HF.

Clinical pharmacology of β-3 adrenergic receptor agonists for cardiovascular diseases

INTRODUCTION

Few agonists of the third isotype of beta-adrenergic receptors, the β3-adrenoreceptor, are currently used clinically, and new agonists are under development for the treatment of overactive bladder disease. As the receptor is expressed in human cardiac and vascular tissues, it is important to understand their beneficial (or adverse) effect(s) on these targets.

AREAS COVERED

We discuss the most recent results of clinical trials testing the benefit and safety of β3-adrenoreceptor activation on cardiovascular outcomes in light of current knowledge on the receptor biology, genetic polymorphisms, and agonist pharmacology.

EXPERT OPINION

While evidence from small clinical trials is limited so far, the β3-agonist, mirabegron seems to be safe in patients at high cardiovascular risk but produces benefits on selected cardiovascular outcomes only at higher than standard doses. Activation of cardiovascular β3-adrenoreceptors deserves to be tested with more potent agonists, such as vibegron.

Urinary dysfunction in patients with vascular cognitive impairment

Vascular cognitive impairment (VCI) is caused by vascular pathologies, with the spectrum of cognitive disorders ranging from subjective cognitive dysfunction to dementia. Particularly among older adults, cognitive impairment is often complicated with urinary dysfunction (UD); some patients may present with UD before cognitive impairment owing to stroke or even when there are white matter hyperintensities on imaging studies. Patients with cognitive impairment often have both language and movement dysfunction, and thus, UD in patients with VCI can often be underdiagnosed and remain untreated. UD has an impact on the quality of life of patients and caregivers, often leading to poor outcomes. Medical history is an important aspect and should be taken from both patients and their caregivers. Clinical assessment including urinalysis, voiding diary, scales on UD and cognitive impairment, post-void residual volume measurement, uroflowmetry, and (video-) urodynamics should be performed according to indication. Although studies on UD with VCI are few, most of them show that an overactive bladder (OAB) is the most common UD type, and urinary incontinence is the most common symptom. Normal urine storage and micturition in a specific environment are complex processes that require a sophisticated neural network. Although there are many studies on the brain-urinary circuit, the specific circuit involving VCI and UD remains unclear. Currently, there is no disease-modifying pharmacological treatment for cognitive impairment, and anti-acetylcholine drugs, which are commonly used to treat OAB, may cause cognitive impairment, leading to a vicious circle. Therefore, it is important to understand the complex interaction between UD and VCI and formulate individualized treatment plans. This review provides an overview of research advances in clinical features, imaging and pathological characteristics, and treatment options of UD in patients with VCI to increase subject awareness, facilitate research, and improve diagnosis and treatment rates.

Rational design, synthesis, and pharmacological evaluation of a cohort of novel beta-adrenergic receptors ligands enables an assessment of structure-activity relationships

Biomedical applications of molecules that are able to modulate β-adrenergic signaling have become increasingly attractive over the last decade, revealing that β-adrenergic receptors (β-ARs) are key targets for a plethora of therapeutic interventions, including cancer. Despite successes in β-AR drug discovery, identification of β-AR ligands that are useful as selective chemical tools in pharmacological studies of the three β-AR subtypes, or lead compounds for drug development is still a highly challenging task. This is mainly due to the intrinsic plasticity of β-ARs as G protein-coupled receptors in conjunction with the requirement for functional receptor subtype selectivity, tissue specificity and minimal off-target effects. With the aim to provide insight into structure-activity relationships for the three β-AR subtypes, we have synthesized and obtained the pharmacological profile of a series of structurally diverse compounds (named MC) that were designed based on the aryloxy-propanolamine scaffold of SR59230A. Comparative analysis of their predicted binding mode within the active and inactive states of the receptors in combination with their pharmacological profile revealed key structural elements that control their activity as agonists or antagonists, in addition to clues about substituents that mediate selectivity for one receptor subtype over the others. We anticipate that these results will facilitate selective β-AR drug development efforts.

Assessing Quality-of-Life of Patients Taking Mirabegron for Overactive Bladder

Lower urinary tract symptoms (LUTS), including urgency, frequency, and urgency incontinence, are highly prevalent in the general population and increase in prevalence with increasing age. All LUTS, but notable urgency and urgency incontinence, are associated with negative impact on quality-of-life (QoL), with multiple aspects of QoL affected. Urgency and urgency incontinence are most commonly caused by overactive bladder (OAB), the clinical syndrome of urinary urgency, usually accompanied by increased daytime frequency and/or nocturia in the absence of infection or other obvious etiology, which may be treated with conservative and lifestyle interventions, bladder antimuscarinic drugs, and, more recently, by mirabegron, a β3 agonist. This narrative review describes the impact of OAB on QoL, quantifies this impact, and outlines the evidence for the use of mirabegron in the treatment of, and improvement in QoL in, people with OAB.

β3 Adrenergic Receptor Agonist Mirabegron Increases AQP2 and NKCC2 Urinary Excretion in OAB Patients: A Pleiotropic Effect of Interest for Patients with X-Linked Nephrogenic Diabetes Insipidus

We previously reported the novel finding that β3-AR is functionally expressed in the renal tubule and shares its cellular localization with the vasopressin receptor AVPR2, whose physiological stimulation triggers antidiuresis by increasing the plasma membrane expression of the water channel AQP2 and the NKCC2 symporter in renal cells. We also showed that pharmacologic stimulation of β3-AR is capable of triggering antidiuresis and correcting polyuria, in the knockout mice for the AVPR2 receptor, the animal model of human X-linked nephrogenic diabetes insipidus (XNDI), a rare genetic disease still missing a cure. Here, to demonstrate that the same response can be evoked in humans, we evaluated the effect of treatment with the β3-AR agonist mirabegron on AQP2 and NKCC2 trafficking, by evaluating their urinary excretion in a cohort of patients with overactive bladder syndrome, for the treatment of which the drug is already approved. Compared to baseline, treatment with mirabegron significantly increased AQP2 and NKCC2 excretion for the 12 weeks of treatment. This data is a step forward in corroborating the hypothesis that in patients with XNDI, treatment with mirabegron could bypass the inactivation of AVPR2, trigger antidiuresis and correct the dramatic polyuria which is the main hallmark of this disease.

The Efficiency and Safety of Mirabegron Monotherapy for the Treatment of Urge Incontinence in Women Aged >80 Years

Objective We aimed to evaluate the efficacy and safety of mirabegron monotherapy in very older (>80 years) women with overactive bladder (OAB) who were discontinued anticholinergic drugs by the other departments. Material and methods The present retrospective study evaluated very older (>80 years) women with OAB who were discontinued anticholinergic drugs by the other departments between May 2018 and January 2021. Efficacy assessments were performed using Overactive Bladder-Validated Eight-Question (OAB-V8) scores before and after mirabegron monotherapy (12 weeks). Safety was evaluated based on adverse events (hypertension, nasopharyngitis, and urinary tract infection), electrocardiography, hypertension measure, uroflowmetry (UFM), and post-voiding. Patient data including demographic characteristics, diagnoses, values before and after mirabegron monotherapy, and adverse events were evaluated. Results A total of 42 very older (>80 years) women with OAB who used mirabegron monotherapy (50 mg per day) were included in this study. Frequency, nocturia, urgency, and total OAB-V8 scores were significantly lower after mirabegron monotherapy than before mirabegron monotherapy (p < 0.05, p < 0.05, p < 0.05, and p < 0.05, respectively). There was no significant difference between systolic-diastolic blood pressure and heart rate before and after mirabegron monotherapy treatment. Conclusion Mirabegron monotherapy is an effective and safe therapy in very older (>80 years) women with OAB.

Sex and Gender Differences in the Pharmacology of the Overactive Urinary Bladder

Dysfunction of the lower urinary tract in general and the overactive bladder syndrome (OAB) in particular are prevalent and have major impact on the quality of life of the afflicted patients and their partners. We concisely review sex and gender differences in patients and animal models in physiological bladder function, its alterations in disease (mostly OAB), and its responses to treatment. Women appear to have a smaller functional bladder capacity and, therefore, must void more often than men. On the other hand, men have a greater bladder outlet resistance, which is partly attributed to a longer urethra and partly to the presence of the prostate. Sex and gender differences in bladder contractility appear small and were not found consistently. The ability of bladder smooth muscle to relax may be somewhat smaller in females. However, females are heavily underrepresented in experimental studies on bladder function. Stress urinary incontinence is found predominantly in women (particularly those after childbirth). OAB is similarly prevalent in men and women. Females seek treatment much more often and are overrepresented in clinical trials. Treatment responses in OAB patients are similar in both genders for oral medications, but improvements upon injections of onabotulinum toxin type A appear smaller in men. We conclude that there is no evidence for major sex and gender differences in bladder dysfunction as related to OAB and its treatment responses, but female animals are heavily underrepresented in experimental studies.

Study of mirabegron and solifenacin in the improvement of catheter-related bladder discomfort in patients undergoing transurethral resection: A case-control study

BACKGROUND

The goal of this study was to see if using mirabegron, solifenacin, or placebo may help patients with transurethral resection avoid catheter-related bladder discomfort (CRBD).

METHODS

Patients who underwent transurethral surgery and were given a catheter for 3 days after surgery were chosen for this study. The enrolled patients were separated into 3 groups: mirabegron (M), solifenacin (S), and a blank control group (C). All patients had their overactive bladder symptoms score (OABSS) and blood pressure checked before surgery. The CRBD, blood pressure, and heart rate were measured at 6, 24, 48, and 72 hours after surgery. The OABSS and side effects were documented on the 7th day.

RESULTS

The 104 patients in this trial were randomized into 3 groups at random: M, S, and C. The ultimate follow-up was completed by 99 patients, including 33 in group M, 33 in group S, and 33 in group C. The OABSS, CRBD, and blood pressure in groups M and S were similar before and after surgery (P > .05). Groups M and S performed much better on the OABSS and CRBD than group C (P < .05). There were no significant differences in blood pressure between the 3 groups (P > .05). There were no significant differences in the occurrences of new onset dry mouth (P = .84) or constipation (P = .64) among the 3 groups.

CONCLUSION

Mirabegron is comparable to solifenacin as an alternative for the prevention of CRBD, making it a viable option for CRBD prevention.

Cost-effectiveness evaluation of mirabegron versus anti-muscarinics and third-line therapies: a systematic review

BACKGROUND

Overactive bladder (OAB) is defined as urinary urgency, usually with urinary frequency and nocturia, with or without urgency urinary incontinence. OAB can interfere with health-related quality of life. The current treatment for OAB includes conservative management, surgery, and pharmacotherapy. Mirabegron is a new drug acting by the mechanism of ß3-adrenoceptor agonism. This study aimed to review the cost-effectiveness of mirabegron in the treatment of OAB.

AREAS COVERED

We searched published articles in electronic search databases. Ten studies were included in the qualitative analysis. Various antimuscarinics, including oxybutynin, fesoterodine, tolterodine, darifenacin, and trospium were compared with mirabegron. The results were evaluated and compared according to the quality-adjusted life-years (QALY), cost/year, and incremental cost-effectiveness ratio (ICER). Of the ten studies in only three, mirabegron was not a cost-effective strategy. In seven cases, mirabegron was cost-effective.

EXPERT OPINION

: Based on our findings, the cost-effectiveness of mirabegron was variable in different regions; however, most of the studies show the cost-effectiveness of mirabegron. Our study illustrates that mirabegron's incremental cost-effectiveness ratio in comparison with its comparators is below the willingness to pay threshold even in the countries with low GDP/Capita. The results also showed that despite the low price and no difference in the effectiveness of mirabegron compared to antimuscarinic drugs, the sensitivity of the study results to adverse effects and supportive therapeutic interventions for patients treated with antimuscarinic drugs. Our proposal for future economic studies for OAB pharmacotherapy is to compare different doses, formulations, and administration forms in a real-world context.

Vibegron for the treatment of overactive bladder: a comprehensive update

INTRODUCTION

: Overactive bladder (OAB) is associated with physical, emotional and financial burden. After failed conservative measures, second-line therapy includes medications, such as antimuscarinics and beta-3 adrenergic receptor (β3AR) agonists. Antimuscarinics are most commonly prescribed but have systemic side effects that lead to poor compliance. β3AR agonists include mirabegron and vibegron. Mirabegron is a first generation β3AR agonist that has shown to be effective for frequency, urgency urinary incontinence (UUI) and urgency, but has interactions with cytochrome P450 enzymes (CYPs) and cardiovascular sequelae. Vibegron is a second generation β3AR agonist that is highly selective and does not interact with CYPs. It has shown to be very effective for reducing UUI episodes and daily micturition number and has a favorable side effect profile.

AREAS COVERED

: Clinical background, pharmacology, and clinical studies for vibegron.Expert opinion: Vibegron is a welcomed addition to the OAB therapeutic landscape. This single dose, once daily option is effective, especially for patients with wet OAB, with a favorable side effect profile. Sub-analyses of patients ≥ 65 years have shown continued efficacy and safety. The few drug interactions are of benefit, especially for older patients with polypharmacy. As long-term data accrues, vibegron has the potential to drive the OAB therapeutic market.

β3 Relaxant Effect in Human Bladder Involves Cystathionine γ-Lyase-Derived Urothelial Hydrogen Sulfide

It is now well established that the urothelium does not act as a passive barrier but contributes to bladder homeostasis by releasing several signaling molecules in response to physiological and chemical stimuli. Here, we investigated the potential contribution of the hydrogen sulfide (H2S) pathway in regulating human urothelium function in β3 adrenoceptor-mediated relaxation. The relaxant effect of BRL 37344 (0.1–300 µM), a selective β3 adrenoceptor agonist, was evaluated in isolated human bladder strips in the presence or absence of the urothelium. The relaxant effect of BRL 37344 was significantly reduced by urothelium removal. The inhibition of cystathionine-γ-lyase (CSE), but not cystathionine-β-synthase (CBS), significantly reduced the BRL 37344 relaxing effect to the same extent as that given by urothelium removal, suggesting a role for CSE-derived H2S. β3 adrenoceptor stimulation in the human urothelium or in T24 urothelial cells markedly increased H2S and cAMP levels that were reverted by a blockade of CSE and β3 adrenoceptor antagonism. These findings demonstrate a key role for urothelium CSE-derived H2S in the β3 effect on the human bladder through the modulation of cAMP levels. Therefore, the study establishes the relevance of urothelial β3 adrenoceptors in the regulation of bladder tone, supporting the use of β3 agonists in patients affected by an overactive bladder.

[Medical treatment of male lower urinary tract symptoms: what's new?]

Decades after the introduction of 5α-reductase inhibitors and α1-adrenoceptor antagonists, new data of practical relevance related to their desired and adverse effects continues to emerge. Some of these novel findings are to be taken seriously but are insufficiently established, for instance associations between drug use and depression or dementia. Multiple combination treatments have been tested. While combination treatment was often statistically superior to monotherapy, the difference was mostly in the range of 1 IPSS point, which raises doubts on the clinical relevance of the findings at the group level. The new evidence enables further personalisation of the treatment of male lower urinary tract dysfunction, but also makes individual risk-benefit considerations more complex.

Associations between the Patient Perception of Bladder Condition score and overactive bladder syndrome symptoms at baseline and upon treatment

BACKGROUND

Patient-reported outcomes such as the Patient Perception of Bladder Condition (PPBC) score are frequently used to characterize overactive bladder syndrome (OAB) patients and their treatment outcomes. However, little information is available on the relationship of such scores to OAB symptoms at the individual patient level.

METHODS

We have performed a post hoc analysis of two large noninterventional studies (n = 1345 and 745) in which patients received propiverine extended release (30 or 45 mg/day) for 12 weeks to determine the strength of nonparametric correlations between PPBC and OAB symptoms at baseline, after treatment and with treatment-associated changes thereof.

RESULTS

PPBC was not correlated with age but with episode frequencies of urgency, incontinence, micturitions, and nocturia, but the strength of correlations was only moderate (Spearman rank correlation coefficient 0.2045-0.3553). Similarly moderate correlations were observed after treatment and when changes in PPBC were compared to those of OAB symptoms, although these correlations were somewhat stronger.

CONCLUSIONS

PPBC is only moderately correlated to OAB symptoms indicating that it characterizes patients beyond what is captured by their symptoms.

Resource use and healthcare costs in patients with overactive bladder who initiate treatment with mirabegron or antimuscarinic monotherapy in Catalonia: the MIRACAT study

INTRODUCTION AND AIM

Overactive bladder (OAB) negatively impacts patient quality of life and may be associated with high resource use. Our aim was to describe the resource use, costs and persistence associated with mirabegron (MB) or antimuscarinic (AM) treatment in patients with OAB.

MATERIALS AND METHODS

Observational retrospective study of medical records in adult patients initiating OAB treatment with MB or AM in Catalonia. Healthcare resource use (visits, hospital stays, tests, medication, absorbent pads) in the first year after treatment initiation was collected. Associated costs were estimated (є, reference year 2019), as well as treatment persistence. Treatment discontinuation was defined as the absence of prescription for at least 45 days or treatment change.

RESULTS

The mean cost per patient (SD) was є 1,640.20 (є 1,227.60) with MB and є 2,159.20 (є 2,264.40) with AM; the associated healthcare resource use cost was lower with MB compared to AM, except for OAB drug costs. Persistence after 12 months of treatment initiation was higher in MB (42.1%) compared to AM (33.0%), as was the median time until treatment discontinuation: 299 (95% CI: 270-328) vs 240 days (95% CI: 230-250).

CONCLUSIONS

Lower healthcare resource use was observed with MB compared to AM in the first year of index treatment, resulting in a lower mean direct cost per patient and year, despite its higher acquisition cost. Increased treatment persistence, as well as rational use of available treatments improves OAB management and, in return, patients' quality of life.

Emerging molecular mechanisms and genetic targets for developing novel therapeutic strategies for treating bladder diseases

Bladder diseases affect millions of patients worldwide and compromise their quality of life with a substantial economic impact. The not fully understood aetiologies of bladder diseases limit the current diagnosis and therapeutic options to primarily symptomatic treatment. In addition, bladder targeted drug delivery is challenging due to its unique anatomical features and its natural physiological function of urine storage and frequent voiding. Therefore, current treatment options often fail to provide a highly effective, precisely targeted and long-lasting treatment. With the growing maturity of gene therapy, comprehensive studies are needed to provide a better understanding of the molecular mechanisms underpinning bladder diseases and help to identify novel gene therapeutic targets and biomarkers for treating bladder diseases. In this review, molecular mechanisms involved in pathology of bladder cancer, interstitial cystitis and overactive bladder syndrome are reviewed, with focus on establishing potential novel treatment options. Proposed novel therapies, including gene therapy combined with nanotechnology, localised drug delivery by nanoparticles, and probiotics, are discussed in regard to their safety profiles, efficacy, treatment lenght, precise targeting, and in comparison to conventional treatment methods.

European Association of Urology Guidelines on the Diagnosis and Management of Female Non-neurogenic Lower Urinary Tract Symptoms. Part 1: Diagnostics, Overactive Bladder, Stress Urinary Incontinence, and Mixed Urinary Incontinence

CONTEXT

Female lower urinary tract symptoms (LUTS) are a common presentation in urological practice. Thus far, only a limited number of female LUTS conditions have been included in the European Association of Urology (EAU) guidelines compendium. The new non-neurogenic female LUTS guideline expands the remit to include these symptoms and conditions.

OBJECTIVE

To summarise the diagnostic section of the non-neurogenic female LUTS guideline and the management of female overactive bladder (OAB), stress urinary incontinence (SUI), and mixed urinary incontinence (MUI).

EVIDENCE ACQUISITION

New literature searches were carried out in September 2021 and evidence synthesis was conducted using the modified GRADE criteria as outlined for all EAU guidelines. A new systematic review (SR) on OAB was carried out by the panel for the purposes of this guideline.

EVIDENCE SYNTHESIS

The important considerations for informing guideline recommendations are presented, along with a summary of all the guideline recommendations.

CONCLUSIONS

Non-neurogenic female LUTS are an important cause of urological dysfunction. Initial evaluation, diagnosis, and management should be carried out in a structured and logical fashion based on the best available evidence. This guideline serves to present this evidence to health care providers in an easily accessible and digestible format.

PATIENT SUMMARY

This report summarises the main recommendations from the European Association of Urology guideline on symptoms and diseases of the female lower urinary tract (bladder and urethra) not associated with neurological disease. We cover recommendations related to diagnosis of these conditions, as well as the treatment of overactive bladder, stress urinary incontinence, and mixed urinary incontinence.

Study Designs for Evaluation of Combination Treatment: Focus on Individual Patient Benefit

Combination treatment, i.e., the use of two or more drugs for the same condition, is frequent in medicine if monotherapy yields an insufficient therapeutic response. We review and challenge clinical study designs and formats of reporting outcomes for the evaluation of the benefit/risk ratio of combination treatment over monotherapy. We demonstrate that benefits of combination treatment at the group level overestimate the probability of benefit at the single patient level based on outcome simulations under almost any imaginable setting. Based on these findings, we propose that studies testing combination treatment should always report on percentages of responders to monotherapy and combination treatment. We provide equations that allow the calculation of the percentage of patients truly benefitting from combination (responders to both monotherapies) and that of patients exposed to risk of harm from adverse effects without a reasonable expectation of individual benefit. These considerations are explained based on real clinical data, mostly from the field of functional urology (male lower urinary tract symptoms).

The Efficacy and Safety of Mirabegron for the Treatment of Neurogenic Lower Urinary Tract Dysfunction: A Systematic Review and Meta-analysis

Background and Objective: Over the past few years, mirabegron has been increasingly used as a therapeutic option for neurogenic lower urinary tract dysfunction. Here, we carried out a meta-analysis to investigate the efficacy and safety of mirabegron for the treatment of neurogenic lower urinary tract dysfunction.

Methods: We used a range of databases to retrieve randomized controlled trials (RCTs) relating to mirabegron in patients with neurogenic lower urinary tract dysfunction: PubMed, Embase, and Cochrane Library; our strategy conformed to the PICOS (populations, interventions, comparators, outcomes, and study designs) strategy.

Results: Our analyses involved four RCTs involving 245 patients. We found that mirabegron treatment resulted in a significant improvement in bladder compliance [mean difference (MD) = 19.53, 95% confidence interval (CI): 14.19 to 24.87, P < 0.00001], urinary incontinence episodes (MD = −0.78, 95% CI: −0.89 to −0.67, P < 0.00001) and Incontinence Quality of Life (I-QOL) (MD = 8.02, 95% CI: 3.20 to 12.84, P = 0.001). Significant differences were detected in terms of Patient Perception of Bladder Condition (PPBC) (MD = −0.54, 95% CI: −1.46 to 0.39, P = 0.26) and urinary urgency episodes (MD = −0.72, 95% CI: −3.1 to 1.66, P = 0.55). With regard to safety, there were no significant differences between mirabegron and control groups in terms of the incidence of drug-related adverse events [odds ratio (OR): 0.83, 95% CI: 0.43 to 1.59, P = 0.57], arrhythmias (OR: 1.27, 95% CI: 0.37 to 4.38, P = 0.70), hypertension (OR: 0.70, 95% CI: 0.13 to 3.82, P = 0.68), or post-voiding residual volume (MD: 1.62, 95% CI: −9.00 to 12.24, P = 0.77).

Conclusion: Mirabegron is an efficacious and safe treatment for patients with neurogenic lower urinary tract dysfunction.

Pharmacological Management of Urinary Incontinence: Current and Emerging Treatment

Pharmacological management of urinary incontinence (UI) is currently based on antimuscarinic and beta-3-agonist drugs. Botulinum toxin A detrusor injections represent an effective but more invasive alternative. This review covers the latest developments of the currently available drugs and the emerging compounds for the treatment of UI. Evidence shows that new antimuscarinics and beta-3-agonists with improved safety profiles may offer unique options to patients intolerant to currently available drugs. Combination therapy proved to be a non-invasive alternative for patients refractory to first-line monotherapy. Exciting advances are ongoing in the research to improve the efficacy/tolerability profile of botulinum toxin, through innovative routes of administration. Several new agents emerged from preclinical studies, some of which have now entered the clinical phase of development and could represent, in the coming years, a new way for the treatment of UI. Recent evidence on the existence of different overactive bladder phenotypes could be the key to tailored treatment. Rather than discovering new molecules, reaching the ability to identify the right drug for the right patient could be the real gamechanger of the future.

The patient pathway for overactive bladder management: A quantitative analysis

PURPOSE

We aimed to explore the pathways followed by patients with overactive bladder (OAB) from referral to the urologist to final treatment.

METHODS

This was a single-center, retrospective cohort study of female patients diagnosed with OAB in a large Dutch nonacademic teaching hospital. The number, sequence, and duration of treatment steps offered were analyzed, and the effectiveness, reasons for discontinuation, and possible case-mix variables influencing OAB treatment were studied.

RESULTS

In total, 120 patients were enrolled and required a median of 2 steps (range, 1-6) of treatment over a median total duration of 28 weeks (range, 5-256). Treatment typically started with drug therapy, including antimuscarinics (38%; 95% CI, 30%-47%), antimuscarinics plus pelvic floor muscle therapy (21%; 95% CI, 15%-29%), or mirabegron (11%; 95% CI, 6%-18%). However, 52% of patients required further treatment, with botulinum toxin A (BoNT-A) injections being most effective (67%; 95% CI, 42%-85%), followed by antimuscarinics plus percutaneous tibial nerve stimulation (50%; 95% CI, 25%-75%), and antimuscarinics plus pelvic floor muscle therapy (36%; 95% CI, 21%-54%). Other therapies showed lower effectiveness. Common reasons for discontinuation were insufficient response and side effects. Overall, 22 patients were lost to follow-up.

CONCLUSION

Most patients try at least two treatments before they experience satisfactory symptom relief, with treatment evaluations requiring time because therapeutic onsets differ by patient and treatment. Our data can help to manage expectations among urologists and patients when seeking treatment for OAB.

Concentration-dependent alpha1-Adrenoceptor Antagonism and Inhibition of Neurogenic Smooth Muscle Contraction by Mirabegron in the Human Prostate

Introduction: Mirabegron is available for treatment of storage symptoms in overactive bladder, which may be improved by β₃-adrenoceptor-induced bladder smooth muscle relaxation. In addition to storage symptoms, lower urinary tract symptoms in men include obstructive symptoms attributed to benign prostatic hyperplasia, caused by increased prostate smooth muscle tone and prostate enlargement. In contrast to the bladder and storage symptoms, effects of mirabegron on prostate smooth muscle contraction and obstructive symptoms are poorly understood. Evidence from non-human smooth muscle suggested antagonism of α₁-adrenoceptors as an important off-target effect of mirabegron. As α₁-adrenergic contraction is crucial in pathophysiology and medical treatment of obstructive symptoms, we here examined effects of mirabegron on contractions of human prostate tissues and on proliferation of prostate stromal cells.

Methods: Contractions were induced in an organ bath. Effects of mirabegron on proliferation, viability, and cAMP levels in cultured stromal cells were examined by EdU assays, CCK-8 assays and enzyme-linked immunosorbent assay.

Results: Mirabegron in concentrations of 5 and 10 μM, but not 1 µM inhibited electric field stimulation-induced contractions of human prostate tissues. Mirabegron in concentrations of 5 and 10 µM shifted concentration response curves for noradrenaline-, methoxamine- and phenylephrine-induced contractions to the right, including recovery of contractions at high concentrations of α₁-adrenergic agonists, increased EC₅₀ values, but unchanged E_max values. Rightshifts of noradrenaline concentration response curves and inhibition of EFS-induced contractions were resistant to L-748,337, l-NAME, and BPIPP. 1 µM mirabegron was without effect on α₁-adrenergic contractions. Endothelin-1- and U46619-induced contractions were not affected or only inhibited to neglectable extent. Effects of mirabegron (0.5–10 µM) on proliferation and viability of stromal cells were neglectable or small, reaching maximum decreases of 8% in proliferation assays and 17% in viability assays. Mirabegron did not induce detectable increases of cAMP levels in cultured stromal cells.

Conclusion: Mirabegron inhibits neurogenic and α₁-adrenergic human prostate smooth muscle contractions. This inhibition may be based on antagonism of α₁-adrenoceptors by mirabegron, and does not include activation of β₃-adrenoceptors and requires concentrations ranging 50-100fold higher than plasma concentrations reported from normal dosing. Non-adrenergic contractions and proliferation of prostate stromal cells are not inhibited by mirabegron.

Efficacy and safety of mirabegron in children and adolescents with neurogenic detrusor overactivity: An open-label, phase 3, dose-titration study

Aims

To evaluate the efficacy and safety of mirabegron in children and adolescents (aged 3 to <18 years) with neurogenic detrusor overactivity (NDO) using clean intermittent catheterization.

Methods

In this open‐label, multicenter, baseline‐controlled, Phase III study (NCT02751931), participants received once‐daily mirabegron at an adult dose equivalent of 25 mg. Dose was increased to 50 mg equivalent unless there were safety/tolerability concerns. The primary efficacy endpoint was change from baseline to Week 24 in maximum cystometric capacity (MCC). Secondary urodynamic assessments, Pediatric Incontinence Questionnaire (PIN‐Q), Patient Global Impression of Severity (PGI‐S), Clinician Global Impression of Change (CGI‐C), and Acceptability questionnaires were included.

Results

Overall, 86 participants (55 aged 3 to <12 years, 31 aged 12 to <18 years) received treatment; 68 were included in efficacy assessments. A statistically significant increase in MCC from baseline to Week 24 was observed (87.20 ml, 95% confidence interval: 66.07, 108.33; p < .001); this increase was apparent from Week 4. Significant increases in bladder compliance, bladder volume until first detrusor contraction, average volume per catheterization, maximum daytime catheterized volume and number of dry days per week. Significant decreases in detrusor pressure and number of leakage episodes per day were also observed. Significant improvement in PGI‐S but not PIN‐Q was observed. Most participants reported their condition had either much or very much improved using the CGI‐C. Mirabegron was well tolerated in this population with a profile aligned with that in adults.

Conclusions

Mirabegron was effective and well‐tolerated in the treatment of pediatric patients with NDO.

Repurposing beta-3 adrenergic receptor agonists for Alzheimer's disease: beneficial effects in a mouse model

Background

Old age, the most important risk factor for Alzheimer’s disease (AD), is associated with thermoregulatory deficits. Brown adipose tissue (BAT) is the main thermogenic driver in mammals and its stimulation, through β3 adrenergic receptor (β3AR) agonists or cold acclimation, counteracts metabolic deficits in rodents and humans. Studies in animal models show that AD neuropathology leads to thermoregulatory deficits, and cold-induced tau hyperphosphorylation is prevented by BAT stimulation through cold acclimation. Since metabolic disorders and AD share strong pathogenic links, we hypothesized that BAT stimulation through a β3AR agonist could exert benefits in AD as well.

Methods

CL-316,243, a specific β3AR agonist, was administered to the triple transgenic mouse model of AD (3xTg-AD) and non-transgenic controls from 15 to 16 months of age at a dose of 1 mg/kg/day i.p.

Results

Here, we show that β3AR agonist administration decreased body weight and improved peripheral glucose metabolism and BAT thermogenesis in both non-transgenic and 3xTg-AD mice. One-month treatment with a β3AR agonist increased recognition index by 19% in 16-month-old 3xTg-AD mice compared to pre-treatment (14-month-old). Locomotion, anxiety, and tau pathology were not modified. Finally, insoluble Aβ42/Aβ40 ratio was decreased by 27% in the hippocampus of CL-316,243-injected 3xTg-AD mice.

Conclusions

Overall, our results indicate that β3AR stimulation reverses memory deficits and shifts downward the insoluble Aβ42/Aβ40 ratio in 16-month-old 3xTg-AD mice. As β3AR agonists are being clinically developed for metabolic disorders, repurposing them in AD could be a valuable therapeutic strategy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13195-021-00842-3.

Dietary glycine improves urine storage symptoms in urology outpatients

OBJECTIVES

Spinal glycinergic mechanisms inhibit the micturition reflex, and administration of glycine inhibits bladder activity in rats. Therefore, we examined whether dietary glycine would improve storage symptoms in urological outpatients.

METHODS

We enrolled 20 participants (16 men and four women) with an overactive bladder symptom score (OABSS) ≥ 3. All participants took 3 g of glucose (placebo) twice a day for the first four weeks, then 3 g of glycine twice a day for the next four weeks. We evaluated blood pressure, international prostate symptom score (IPSS), nocturia quality of life (N-QOL) score, OABSS, frequency of urination, sleep latency, time to first nighttime void, bladder pain, global self-assessment (GSA) evaluated urinary symptom improvement, and adverse events.

RESULTS

Glucose administered as a placebo improved urinary frequency, urine force on the IPSS, and five of the 13 items on the N-QOL. However, compared to the results before and after glucose administration, glycine treatment decreased the number of nocturnal voids, urgency, and total score for urine storage items on the IPSS. It also reduced blood pressure and improved IPSS-QOL. For the OABSS, improvements with glycine were noted in the number of nocturnal urinations, urinary urgency, urge incontinence, and total score. For the N-QOL, eight of 13 items, and the total score, improved. The actual number of nighttime urinations, sleep latency, latency to first nighttime urination, bladder pain, and GSA also improved. There were no adverse events.

CONCLUSIONS

Glycine might improve urine storage symptoms, cardiovascular function, pain, and sleep.

Possible Involvement of Muscarinic Receptor Blockade in Mirabegron Therapy for Patients with Overactive Bladder

The selective β ₃-adrenoceptor agonist mirabegron, an established alternative to antimuscarinic therapy for patients with overactive bladder, induces additional effects against receptors, transporters, and hepatic enzymes. The present study aimed to elucidate the effects of mirabegron on muscarinic receptors in the rat bladder using radioligand binding and functional assays. Mirabegron (0.1-100 μM) inhibited specific [N-methyl-³H]scopolamine methyl chloride binding in the bladder and other tissues of rats in a concentration-dependent manner. Binding affinity in the bladder was similar to that in the heart and significantly higher than those in the submaxillary gland and brain. Mirabegron induced the concentration-dependent relaxation of carbachol-induced contractions in the rat isolated bladder. Further analyses using a two-site model revealed that the relative quantities of high- and low-affinity components for mirabegron were 44.5% and 55.5%, respectively. Respective pEC₅₀ values were 7.06 and 4.97. Based on the receptor binding affinity and pharmacokinetics of mirabegron, muscarinic receptor occupancy in the human bladder for 24 hours after the administration of a single oral dose of 50 mg mirabegron was 37%-76%. The present results demonstrate for the first time that mirabegron may relax the detrusor smooth muscle not only by β ₃-adrenoceptor activation but also muscarinic receptor blockade. SIGNIFICANCE STATEMENT: Mirabegron, the first selective β ₃-adrenoceptor agonist, represents an alternative to antimuscarinic agents for management of overactive bladder (OAB). The present study aimed to clarify whether mirabegron directly binds to muscarinic receptors and affects cholinergic agonist-induced contractions in rat urinary bladder and to predict muscarinic receptor occupancy in human bladder after oral administration of mirabegron. The results demonstrated that mirabegron therapy for patients with OAB may be due not only to β ₃-adrenoceptor activation but also muscarinic receptor blockade.

Cardiovascular safety of mirabegron in individuals treated for spinal cord injury- or multiple sclerosis-induced neurogenic detrusor overactivity

PURPOSE

To analyze cardiovascular safety of mirabegron in patients with spinal cord injury (SCI)- and multiple sclerosis (MS)-induced neurogenic detrusor overactivity (NDO) in a prospective, randomized, double-blind, placebo-controlled study.

METHODS

Seventy-eight patients were enrolled into the study, and 66 of them were included into the final analysis. In 49 (74.2%), NDO developed due to suprasacral SCI, 17 (25.8%) suffered from NDO due to MS. Eleven patients were previously treated for hypertension and one for arrhythmia. All study participants received placebo for 2 weeks run-in period. Subsequently, eligible subjects were randomized for 4 weeks of active treatment with mirabegron 50 mg once daily (Group A; n = 32) or placebo (Group B; n = 34). Data from resting electrocardiography (ECG), 24-h ECG and blood pressure monitoring, and echocardiographic examination, were used for cardiovascular safety assessment. All reported variables were evaluated at time of randomization and at the end of the study. Longitudinal changes of variables within the groups and differences between the groups were assessed using nonparametric Kruskal-Wallis test, and p ≤ 0.05 was considered statistically significant.

RESULTS

No statistically significant longitudinal changes were found in safety variables, except for prolongation of QT interval in placebo group (p = 0.0328) recorded by resting ECG. No significant difference between the Groups A and B, in any of the variables, was observed. A single cardiovascular study drug-related adverse event was recorded in a patient with cervical SCI (3.13%).

CONCLUSIONS

Our results suggest that mirabegron can be safely used in the treatment of patients with SCI- and MS-induced NDO.

Mirabegron Add-On Therapy to Tamsulosin in Men with Overactive Bladder: Post Hoc Analyses of Efficacy from the MATCH Study

INTRODUCTION

MATCH was a randomized, double-blind, placebo-controlled study enrolling Japanese and Korean men aged ≥ 40 years who still had overactive bladder (OAB) symptoms while receiving tamsulosin. After a 4-week single-blind screening period in which patients received placebo and tamsulosin, patients were randomized to mirabegron 50 mg + tamsulosin or placebo + tamsulosin for 12 weeks (n = 568). This post hoc analysis investigated the proportion of treatment responders for each treatment group and for subgroups stratified by age based on voiding diaries and patient-reported outcomes (PROs).

METHODS

Responders were defined as those achieving normalization or clinically meaningful improvements in efficacy, or clinically important differences in PROs [≥ 10-point improvement in OAB questionnaire (OAB-q) symptom bother or total health-related quality of life (HRQoL) subscales at end of treatment (EoT; minimally important difference [MID]) or OAB symptom score (OABSS) total score decreased by ≥ 3 points at EoT [minimally clinically important change (MCIC)]].

RESULTS

At EoT, micturition frequency normalization was achieved by 30.7% of tamsulosin + mirabegron patients and 18.6% of tamsulosin + placebo patients. Normalization of urgency and incontinence was 19.1% and 60.7% for tamsulosin + mirabegron and 18.2% and 60.0% for tamsulosin + placebo. Normalization of OAB symptoms based on OABSS was 17.1% for tamsulosin + mirabegron and 14.5% for tamsulosin + placebo. Higher proportions of patients in the mirabegron add-on group versus the placebo group reported clinically meaningful improvements in micturitions, urgency, and incontinence and in MCIC for OABSS and MID for the OAB-q subscales. Double- and triple-responder findings were as predicted by the results of single-responder analyses. These results were mirrored in the age groups using cut-offs of 65 and 75 years.

CONCLUSION

Mirabegron therapy added on to tamsulosin resulted in a higher frequency of responders in terms of normalization (e.g., micturition frequency normalization), clinically meaningful improvements in efficacy (e.g., ≥ 50% decrease in urgency), and minimally important changes in PROs (e.g., MCIC in OABSS).

TRIAL REGISTRATION

ClinicalTrials.gov identifier, NCT02656173.