Mirabegron - a selective β3-adrenoreceptor agonist for the treatment of overactive bladder

Ageing and the Autonomic Nervous System

The vertebrate nervous system is divided into central (CNS) and peripheral (PNS) components. In turn, the PNS is divided into the autonomic (ANS) and enteric (ENS) nervous systems. Ageing implicates time-related changes to anatomy and physiology in reducing organismal fitness. In the case of the CNS, there exists substantial experimental evidence of the effects of age on individual neuronal and glial function. Although many such changes have yet to be experimentally observed in the PNS, there is considerable evidence of the role of ageing in the decline of ANS function over time. As such, this chapter will argue that the ANS constitutes a paradigm for the physiological consequences of ageing, as well as for their clinical implications.

Changes in overactive bladder medication following bariatric surgery: segmented regression analysis

PURPOSE

Bariatric surgery has shown reductions in overactive bladder (OAB) symptoms; however, the impacts on OAB treatment is unknown. The goal of our study is to evaluate the impact of bariatric surgery on OAB medication utilization.

METHODS

We used IBM^® MarketScan^® commercial databases from 2005 to 2018. We included patients aged  ≥ 18 years with 360 days of continuous enrollment before and after bariatric surgery (Roux-en-Y Gastric Bypass and Sleeve Gastrectomy) with at least one fill of an OAB medication in the 360 days prior to bariatric surgery. We evaluated all included patients and stratified by surgery type and patient sex. Segmented regression analyses were used to assess the proportion of patients on OAB medications before and after bariatric surgery. We replicated our findings using hip or knee replacement surgery as a negative control.

RESULTS

Among the included patients (n = 3069), 92.2% were females, 58.6% underwent Roux-en-Y Gastric Bypass. Immediately following bariatric surgery, the proportion of patients treated with an OAB medication reduced from 34.8 to 14.1% (p < 0.001) resulting in a 59.5% relative reduction. Patients who underwent Roux-en-Y Gastric Bypass vs. Sleeve Gastrectomy (63.8% vs. 55.1%) relative reduction (p = 0.009)) and females versus males [62.3% vs. 52.9% relative reduction (p < 0.001)] had a more pronounced reduction in OAB medication use. There was slight decrease in OAB medication use in the negative control analysis.

CONCLUSIONS

A reduction in OAB medication use following bariatric surgery may be associated with a reduction in OAB symptoms suggesting an additional benefit of bariatric surgery.

Real-World Effects of Mirabegron in Patients with Chronic Neurogenic Detrusor Overactivity - A Retrospective Cohort Study

PURPOSE

To investigate the tolerability and the effects of the β-3-adrenoceptor-agonist mirabegron on urinary incontinence and urodynamic parameters in patients with chronic neurogenic detrusor overactivity (NDO).

PATIENTS AND METHODS

The patient database of a spinal cord injury rehabilitation center in Switzerland was screened for patients with chronic (>12 months) NDO, who had been prescribed mirabegron. Patient characteristics, data regarding bladder management, urinary incontinence and concurrent medication for NDO as well as urodynamic parameters were collected retrospectively. The changes in the urodynamic parameters and the occurrence of urinary incontinence over time were investigated.

RESULTS

The data of 63 patients with a median age of 48 years and a median NDO duration of 8.9 years at the initiation of the mirabegron treatment were analyzed. A median 3.0 and 12.7 months had elapsed from the initiation of the mirabegron therapy to the first and second follow-up evaluation, respectively. The majority of patients (73%) received mirabegron in combination with an established antimuscarinic or onabotulinum toxin therapy. The number of patients suffering from urinary incontinence decreased significantly (p≤0.005) from 60.3% (95% CI 47.2/72.4%) to 38.1% (95% CI 23.6/54.4%). Furthermore, the maximum detrusor pressure during the storage phase was significantly (p≤0.04) lower at the second follow-up evaluation (29.5cmH₂O, 95% CI 22/40cmH₂O) compared to before the mirabegron treatment (35cmH₂O, 95% CI 29/41cmH₂O). The bladder capacity and detrusor compliance were significantly (p≤0.005) increased during the mirabegron treatment. No patient had discontinued the mirabegron treatment as a result of side effects.

CONCLUSION

Mirabegron demonstrated a clinically relevant effect and a good safety profile. Concomitant treatment of NDO with mirabegron may allow reduction in the dose of antimuscarinic medication and thus, improve the long-term persistence of NDO treatment.

Mirabegron in the Treatment of Overactive Bladder: Safety and Efficacy in the Very Elderly Patient

Lower urinary tract symptoms, including urgency, urgency incontinence, frequency, and nocturia, are highly prevalent in older adults and are associated with significant morbidity and impairment in quality of life. When conservative measures such as bladder training fail to improve symptoms, pharmacological management is recommended by national and international guidelines. Mirabegron, an agonist of the β3 adrenergic receptor, demonstrates similar efficacy to the anticholinergic drugs without the risk of anticholinergic effects, but experience and evidence in the very elderly population are limited. This narrative review examines the current evidence base for mirabegron in very elderly adults.

A Novel Alternative in the Treatment of Detrusor Overactivity? In Vivo Activity of O-1602, the Newly Synthesized Agonist of GPR55 and GPR18 Cannabinoid Receptors

The aim of the research was to assess the impact of O-1602—novel GPR55 and GPR18 agonist—in the rat model of detrusor overactivity (DO). Additionally, its effect on the level of specific biomarkers was examined. To stimulate DO, 0.75% retinyl acetate (RA) was administered to female rats’ bladders. O-1602, at a single dose of 0.25 mg/kg, was injected intra-arterially during conscious cystometry. Furthermore, heart rate, blood pressure, and urine production were monitored for 24 h, and the impact of O-1602 on the levels of specific biomarkers was evaluated. An exposure of the urothelium to RA changed cystometric parameters and enhanced the biomarker levels. O-1602 did not affect any of the examined cystometric parameters or levels of biomarkers in control rats. However, the O-1602 injection into animals with RA-induced DO ameliorated the symptoms of DO and caused a reversal in the described changes in the concentration of CGRP, OCT₃, BDNF, and NGF to the levels observed in the control, while the values of ERK1/2 and VAChT were significantly lowered compared with the RA-induced DO group, but were still statistically higher than in the control. O-1602 can improve DO, and may serve as a promising novel substance for the pharmacotherapy of bladder diseases.

Cardiovascular risk profile in individuals initiating treatment for overactive bladder - Challenges and learnings for comparative analysis using linked claims and electronic medical record databases

For managing overactive bladder (OAB), mirabegron, a β3 adrenergic receptor agonist, is typically used as second-line pharmacotherapy after antimuscarinics. Therefore, patients initiating treatment with mirabegron and antimuscarinics may differ, potentially impacting associated clinical outcomes. When using observational data to evaluate real-world safety and effectiveness of OAB treatments, residual bias due to unmeasured confounding and/or confounding by indication are important considerations. Falsification analysis, in which clinically irrelevant endpoints are tested as a reference, can be used to assess residual bias. The objective in this study was to compare baseline cardiovascular risk among OAB patients by treatment, and assess the presence of residual bias via falsification analysis of OAB patients treated with mirabegron or antimuscarinics, to determine whether clinically relevant comparisons across groups would be feasible. Linked electronic health record and claims data (Optum/Humedica) for OAB patients in the United States from 2011-2015 were available, with index defined as first date of OAB treatment during this period. Unadjusted characteristics were compared across groups at index and propensity-matching conducted. Falsification endpoints (hepatitis C, shingles, community-acquired pneumonia) were compared between groups using odds ratios (ORs) and 95% confidence intervals (CI). The study identified 10,311 antimuscarinic- and 408 mirabegron-treated patients. Mirabegron patients were predominantly older males, with more comorbidities. The analytic sample included 1,188 antimuscarinic patients propensity-matched to 396 mirabegron patients; after matching, no significant baseline differences remained. Estimates of falsification ORs were 0.7 (CI:0.3-1.7) for shingles, 1.5 (CI:0.3-8.2) for hepatitis C, 0.8 (CI:0.4-1.8) and 0.9 (CI:0.6-1.4) for pneumonia. While propensity matching successfully balanced observed covariates, wide CIs prevented definitive conclusions regarding residual bias. Accordingly, further observational comparisons by treatment group were not pursued. In real-world analysis, bias-detection methods could not confirm that differences in cardiovascular risk in patients receiving mirabegron versus antimuscarinics were fully adjusted for, precluding clinically relevant comparisons across treatment groups.

Overactive bladder syndrome pharmacotherapy: future treatment options

Overactive bladder syndrome (OAB) is a lifestyle disease and its incidence increases with age. Although it is not a life-threatening disease, it is known to have a significant impact on the quality of life. The first-choice pharmacological treatment of OAB is antimuscarinics. However, their limited clinical effectiveness and unsatisfactory tolerance profile, combined with the advancement of knowledge on the aetiopathogenesis of the disease, have inspired research on new pharmacotherapy options for OAB. Basic research has provided foundations for the development of new OAB treatments, which seem very promising and can be applied in clinical practice. The mechanisms of the studied compounds are based on their effect on certain receptors and neurotransmitters that contribute to regulating the micturition reflex. These compounds are not only more receptor-specific as compared to currently used drugs, but also some of them are organ-specific. Some of such compounds have already passed the proof-of-concept stage of development and have the therapeutic potential to determine the future of OAB pharmacotherapy. This review focuses on the mechanisms of substances that are now undergoing pre-clinical and clinical tests and their effects on the micturition cycle, while also identifying opportunities for using them with specific groups of patients. Due to the fact that OAB is a disease of symptoms and its aetiopathogenesis is complex, it seems that modern treatment methods should be tailor-made and based on the pathophysiological mechanisms that induce disease symptoms, rather than only treating the symptoms by inhibiting the contractility of the urinary bladder.