Treatment Patterns with Mirabegron and Antimuscarinics for Overactive Bladder: A Prospective, Registry Study in Taiwan and South Korea (FAITH)

INTRODUCTION

This study aimed to assess overactive bladder (OAB) treatment patterns and factors associated with effectiveness and persistence.

METHODS

A prospective, longitudinal, observational registry study of adults starting OAB therapy with mirabegron or antimuscarinics was undertaken. Primary endpoints were time from treatment initiation to discontinuation/switching; proportion who discontinued/switched; and reasons for discontinuation/switching. Secondary endpoints included OAB Symptom Score (OABSS), OAB Questionnaire: Short Form, and OAB Bladder Assessment Tool scores; factors associated with effectiveness and persistence; and safety.

RESULTS

In total, 556 patients initiating mirabegron and 250 initiating antimuscarinics were enrolled. There was no treatment switch, change, or discontinuation in 68.5% of the mirabegron initiator group and median time to treatment change was not reached. Mean initial treatment duration was 130.8 days. In multivariable models, baseline OABSS was the only variable significantly associated with change from baseline in OABSS, and patients with mild and moderate OAB had significantly better persistence with mirabegron than those with severe OAB. Urinary tract infection was the most common adverse event with mirabegron. There was no treatment switch, change, or discontinuation in 60.4% of the antimuscarinics initiator group and median time to treatment change was not reached. Solifenacin was the most frequent initial treatment (66.0%). Mean treatment duration was 122.2 days. In multivariable models, baseline OABSS was the only variable significantly associated with change from baseline in OABSS, while patients with OAB medication in the 12 months before enrollment had significantly better persistence with antimuscarinics than those with no previous OAB medication. Dry mouth was the most common adverse event with antimuscarinics.

CONCLUSIONS

Mirabegron and solifenacin were commonly prescribed as first-line OAB medications. There was no treatment switch, change, or discontinuation in more than 60% of the mirabegron initiator and antimuscarinics initiator groups. Mean initial treatment duration was 130.8 days and 122.2 days for mirabegron and antimuscarinics, respectively. Graphical Abstract available for this article.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03572231.

Safety and efficacy of an α1 -blocker plus mirabegron compared with an α1 -blocker plus antimuscarinic in men with lower urinary tract symptoms secondary to benign prostatic hyperplasia and overactive bladder: A systematic review and network meta-analysis

AIM

Antimuscarinics and the β3-adrenoreceptor agonist, mirabegron, are commonly used for treating patients with overactive bladder (OAB) and α1 -adrenoreceptor antagonists (α1 -blockers) are the main pharmacological agents used for treating lower urinary tract symptoms (LUTS) secondary to benign prostatic hyperplasia (BPH). As these conditions commonly occur together, the aim of this systematic review was to identify publications that compared the use of an α1 -blocker plus mirabegron with an α1 -blocker plus antimuscarinic in men with LUTS secondary to BPH and OAB. A meta-analysis was subsequently conducted to explore the safety and efficacy of these combinations.

METHODS

Included records had to be from a parallel-group, randomized clinical trial that was ≥8 weeks in duration. Participants were male with LUTS secondary to BPH and OAB. The indirect analyses that were identified compared an α1 -blocker plus OAB agent with an α1 -blocker plus placebo. The PubMed/Medical Literature Analysis and Retrieval System Online, the Excerpta Medica Database, the Cochrane Central Register of Controlled Trials, and the ClinicalTrials.gov registry were searched for relevant records up until March 5, 2020. Safety outcomes included incidences of overall treatment-emergent adverse events (TEAEs) and urinary retention, postvoid residual volume, and maximum urinary flow (Qmax ). Primary efficacy outcomes were micturitions/day, incontinence episodes/day, and urgency episodes/day, and secondary outcomes were Overactive Bladder Symptom Score and International Prostate Symptom Score. A Bayesian network meta-analysis approach was used for the meta-analysis.

RESULTS

Out of a total of 1039 records identified, 24 were eligible for inclusion in the meta-analysis. There were no statistically significant differences between the α1 -blocker plus mirabegron and α1 -blocker plus antimuscarinic groups in terms of the comparisons identified for all the safety and efficacy analyses conducted. Numerically superior results were frequently observed for the α1 -blocker plus mirabegron group compared with the α1 -blocker plus antimuscarinic group for the safety parameters, including TEAEs, urinary retention, and Qmax . For some of the efficacy parameters, most notably micturitions/day, numerically superior results were noted for the α1 -blocker plus antimuscarinic group. Inconsistency in reporting and study variability were noted in the included records, which hindered data interpretation.

CONCLUSION

This systematic review and meta-analysis showed that an α1 -blocker plus mirabegron and an α1 -blocker plus antimuscarinic have similar safety and efficacy profiles in male patients with LUTS secondary to BPH and OAB. Patients may, therefore, benefit from the use of either combination within the clinical setting.

TRPA1 promotes cisplatin-induced acute kidney injury via regulating the endoplasmic reticulum stress-mitochondrial damage

BACKGROUND

Cisplatin is a widely used and effective chemotherapeutic agent against cancer. However, nephrotoxicity is one of the most common side effects of cisplatin, and it can proceed to acute kidney injury (AKI). Studies have reported that activation of transient receptor potential ankyrin-1 (TRPA1) mediates cisplatin-induced renal tubular cytotoxic injury. The aim of this study was to investigate the mechanism of TRPA1 in promoting cisplatin-induced AKI through modulation of the endoplasmic reticulum stress (ERS)-mitochondrial damage.

METHODS

A cisplatin-induced HK-2 cell model in vitro and mouse model in vivo were established. The mechanism of TRPA1 promotes AKI was elucidated by H&E staining, TUNEL staining, transmission electron microscope (TEM), immunofluorescence, CCK-8 viability assays, flow cytometry, Western blotting, JC-1 assay, and enzyme linked immunosorbent assay (ELISA).

RESULT

In vivo and in vitro, HC-030031 reduced cisplatin-induced Scr and BUN level elevations; improved cisplatin-induced renal tissue injury, apoptosis, and mitochondrial dysfunction; elevated the reduced ERS-associated proteins glucose-regulated protein 78 (GRP78), glucose-regulated protein 75 (GRP75), and C/EBP homologous protein (CHOP) levels induced by cisplatin; reduced the elevated optic atrophy 1 (OPA1), mito-fusion 1 (MFN1), and mito-fusion 2 (MFN2) protein levels, and elevated phospho-dynamin-related protein 1 (p-DRP1) and mitochondrial fission factor (MFF) protein levels. HC-030031 also reduced the mitochondria-associated endoplasmic reticulum membrane (MAM) structure. In addition, TRPA1 agonists also decreased cell proliferation, increased apoptosis, and triggered mitochondrial dysfunction and calcium overload in HK-2 cells via modulation of MAM. ERS inhibitors and GRP75 inhibitors reversed these changes caused by TRPA1 agonists.

CONCLUSION

Our findings suggest that TRPA1 enhances cisplatin-induced AKI via modulation of ERS and mitochondrial damage.

Current optimal pharmacologic therapies for overactive bladder

INTRODUCTION

Overactive bladder (OAB) is a common syndrome in adults. Current pharmacologic treatment includes antimuscarinic agents and β-3 adrenoceptor agonists. For non-responders to oral medication, intravesical injection of botulinum toxin A (BoNT-A) is an effective option. However, these treatments have potential adverse events and should be cautiously selected for appropriate patients. This review presents the recently published results of clinical trials and studies for patients with OAB and the underlying pathophysiology of OAB. Appropriate medical therapy based on pathophysiology of OAB is also presented.

AREAS COVERED

Literature search from Pubmed from 2001 to 2023 including clinical background, pharmacology, and clinical studies for OAB medications.

EXPERT OPINION

Treatment of OAB syndrome with any antimuscarinic or β-3 adrenoceptor agonist is feasible as a first-line approach. For patients with suboptimal therapeutic effect to full-dose antimuscarinics or mirabegron, combination with both drugs can improve efficacy. Intravesical BoNT-A 100-U injection provides therapeutic effects for refractory OAB. Patients who are refractory to initial pharmacotherapies should be investigated for the underlying pathophysiology; then an appropriate medication can be added, such as an α1-blocker or anti-inflammatory agents. Patient education about behavioral modification and therapies should always be provided with oral medication or BoNT-A injection for OAB patients.

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.

Mirabegron in medical expulsive therapy for distal ureteral stones: a prospective, randomized, controlled study

OBJECTIVE

To observe the efficacy and safety of Mirabegron in patients with distal, ureteral stones ≤ 10 mm.

PATIENTS AND METHODS

A total of 90 patients with distal ureteral stones ≤ 10 mm were prospectively randomized into two groups. Forty-five cases in the study group and 45 cases as control. The stone-free rates (SFRs) and renal colic episodes between two groups were compared at the 1st, 2nd and 4th week end by imaging examinations.

RESULT

All of 90 patients were randomly assigned to two groups. In patients with ≤ 5 mm stones, the SFRs in the 1st week (63.6% vs. 33.3%, P = 0.040), the 2nd week (86.4% vs. 54.2%, P = 0.018), and the 4th week (90.9% vs. 66.7%, P = 0.046) after treatment were all significantly higher than that in the control group by the stratification analysis of stone size. Even though SFRs were all higher for patients with > 5 mm stones in study group, there was no statistically significant difference (All P > 0.05). In terms of renal colic episodes, the frequency of occurrence of the study group was significantly lower than that of the control group and need less antalgic.

CONCLUSIONS

The MET with Mirabegron has a significant role in improve SFR for the patients with distal ureteral stones ≤ 5 mm and no effect in > 5 mm stones. Furthermore, Mirabegron reduces the need for antalgic in ≤ 10 mm stones with low incidence of adverse effects.

Monotherapy with mirabegron had a better tolerance than the anticholinergic agents on overactive bladder: A systematic review and meta-analysis

BACKGROUND

We conducted this meta-analysis to explore the tolerance of monotherapy with mirabegron (50 mg) on an overactive bladder, compared with a common dosage of anticholinergic agents.

MATERIALS AND METHODS

A comprehensive search for all randomized controlled trials that evaluated the safety of mirabegron and anticholinergic agents on overactive bladder was performed, and we searched the Cochrane Central Register of Controlled trials databases, Pubmed, Embase, and relevant trials from 2013.02 to 2019.10.

RESULTS

Eight studies included 5500 patients with treatment of monotherapy on overactive bladder were identified. The total number of treatment-emergent adverse events had no significantly difference between two monotherapies (RR = 0.88 95%CI: 0.76-1.01; P = .08); however, patients would have a better tolerance with mirabegron (50 mg) in adverse events of dry mouth (RR = 0.42; 95%CI: 0.33-0.53; P < .01) and tachycardia (RR = 0.52; 95%CI: 0.29-0.94; P = .03); and there were no significant differences between two groups in hypertension (RR = 1.02; 95%CI: 0.80-1.30; P = .90), constipation (RR = 0.91; 95%CI: 0.65-1.26; P = 0.57), blurred vision (RR = 1.03; 95%CI: 0.60-1.77; P = 0.92), and urinary tract infection (RR = 0.90; 95%CI: 0.70-1.16; P = .41).

CONCLUSIONS

Treatment-emergent adverse events in patients with overactive bladder who underwent monotherapy of mirabegron (50 mg) or the anticholinergic agents had no significant differences, but mirabegron has a better tolerance in the aspect of dry mouth and tachycardia.

A study of cancer occurrence in users of mirabegron and antimuscarinic treatments for overactive bladder

OBJECTIVE

This post-authorization safety study (EU PAS Register Number: EUPAS16088) was designed to compare the incidence of cancer outcomes in patients treated with mirabegron versus antimuscarinic medications.

METHODS

Cohorts of mirabegron initiators during 2012-2018 were propensity-score matched to antimuscarinic medication initiators within real-world data sources (Danish National Registers, Swedish National Registers, Clinical Practice Research Datalink [UK], Optum [US], and Humana [US]). Incident cancer cases were identified during follow-up from direct linkage to cancer registers or validated through medical record review or through physician questionnaires. Comparisons of sex-specific composite cancer outcomes (cancer of the lung/bronchus, colon/rectum, melanoma of skin, urinary bladder, non-Hodgkin lymphoma, kidney/renal pelvis, pancreas, prostate in men and breast and uterus in women) were made overall and for person-time in the first year and after the first year following start of treatment, for all ages and for the subgroup ≥65 years.

RESULTS

Among the 80,637 mirabegron initiators matched to 169,885 antimuscarinic medication initiators, 68% were at least 65 years of age and 66% were women. Over 5000 incident cancer cases were observed overall. Incidence rates were higher for men than women for composite and individual cancer outcomes. The pooled fixed effects hazard ratios for composite cancer outcomes (all ages) were 1.05 (95% confidence interval [CI]: 0.98-1.14) for women and 1.06 (95% CI: 0.98-1.14) for men. Results were similar in persons ≥65 years.

CONCLUSIONS

The results suggest no association between mirabegron use and risk of cancer, compared with antimuscarinic medications, in either men or women. Registration: EU PAS Register Number: EUPAS16088.

Comparative Safety and Efficacy of Treatments for Overactive Bladder Among Older Adults: A Network Meta-analysis

BACKGROUND

Cumulative exposure to one or more anticholinergic medications ("anticholinergic burden") is associated with an increased risk of adverse outcomes, particularly among older individuals. Mirabegron, an oral selective β3-adrenergic receptor agonist, has demonstrated efficacy in managing the symptoms of overactive bladder without contributing to anticholinergic burden. However, it is not known whether the favorable safety profile of mirabegron relative to antimuscarinics varies with increasing age among a patient population who may have a high anticholinergic burden.

OBJECTIVE

The primary objective of this study was to indirectly compare the safety and efficacy profile of mirabegron relative to antimuscarinics in older adults with overactive bladder.

METHODS

A systematic literature review was conducted to identify randomized controlled trials that reported safety and efficacy endpoints among patients aged ≥ 65 years. Identified randomized controlled trials were subsequently synthesized via a network meta-analysis. Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines in designing, performing, and reporting the literature review were followed. In line with current best practices, the network meta-analysis was conducted using a Bayesian approach and according to the overall general guidance for evidence synthesis developed by the National Institute for Health and Care Excellence decision support unit. Estimates of relative safety were assessed via the odds ratio and estimates of relative efficacy were assessed via means and credible intervals.

RESULTS

A total of 3078 abstracts, 300 of which underwent full-text screening, were identified using the search criteria. Twenty articles reporting on 21 randomized controlled trials were eligible for data extraction and synthesis. Following review, five safety and five efficacy endpoints were considered for inclusion in the network meta-analysis. Regarding findings typical of anticholinergic exposure in older adults, mirabegron was not associated with an increased odds of dry mouth (odds ratio 95% credible interval 0.76 [0.26-2.37]) or constipation (1.08 [0.39-3.02]) relative to placebo, whereas antimuscarinics were strongly associated with these events (odds ratio range 3.78-7.85 and 2.12-4.66, respectively). In this older population, mirabegron was associated with a similar odds of experiencing adverse event-related treatment discontinuations relative to placebo (0.99 [0.57-1.70]), while the odds of experiencing an adverse event-related treatment discontinuation for antimuscarinics had a range of 1.14-3.03 (in most cases, the association was mild). No increased odds of experiencing overall treatment-emergent adverse events was observed for mirabegron or antimuscarinics (odds ratio range 1.25-1.55), apart from fesoterodine (2.23 [1.37-3.37]). Finally, a similar treatment effect was observed across all efficacy endpoints between mirabegron and antimuscarinics in this older population.

CONCLUSIONS

This study indicates that the safety and efficacy profile of mirabegron remains favorable compared with antimuscarinics among older adults. This includes safety outcomes typically associated with anticholinergic burden, which were less frequently observed in patients treated with mirabegron.

Cognitive Effects of Anticholinergic Load in Women with Overactive Bladder

Overactive bladder syndrome (OAB) is defined as urinary urgency, usually accompanied by frequency and nocturia, with or without urgency incontinence, in the absence of urinary tract infection or other obvious pathology. The mainstay of treatment of OAB is anticholinergic/antimuscarinic medication. These drugs block muscarinic receptors throughout the body, not only the bladder, including in the brain, which may lead to cognitive side effects. Anticholinergic load or burden is the cumulative effect of taking drugs that are capable of producing anticholinergic adverse effects. The elderly are more susceptible to these effects, especially as there is increased permeability of the blood brain barrier. The anticholinergic drugs for OAB are able to enter the central nervous system and lead to central side effects. There is increasing evidence that a high anticholinergic load is linked to the development of cognitive impairment and even dementia. Some studies have found an increased risk of mortality. In view of this, care is needed when treating OAB in the elderly. Trospium chloride is a quaternary amine anticholinergic, which has a molecular structure, which theoretically means it is less likely to cross the blood brain barrier and exert central side effects. Alternatively, mirabegron can be used, which is a beta-3 adrenoceptor agonist, which does not add to the anticholinergic load or exert central nervous system side effects. Conservative therapy can be used as an alternative to pharmacological treatment in the form of behavioral modification, fluid management and bladder retraining. Neuromodulation or the use of botox can also be alternatives, but success may be less in the older adult and will require increased hospital attendances.

Chronic mirabegron treatment increases human brown fat, HDL cholesterol, and insulin sensitivity

BACKGROUNDMirabegron is a β3-adrenergic receptor (β3-AR) agonist approved only for the treatment of overactive bladder. Encouraging preclinical results suggest that β3-AR agonists could also improve obesity-related metabolic disease by increasing brown adipose tissue (BAT) thermogenesis, white adipose tissue (WAT) lipolysis, and insulin sensitivity.METHODSWe treated 14 healthy women of diverse ethnicities (27.5 ± 1.1 years of age, BMI of 25.4 ± 1.2 kg/m2) with 100 mg mirabegron (Myrbetriq extended-release tablet, Astellas Pharma) for 4 weeks in an open-label study. The primary endpoint was the change in BAT metabolic activity as measured by [18F]-2-fluoro-d-2-deoxy-d-glucose (18F-FDG) PET/CT. Secondary endpoints included resting energy expenditure (REE), plasma metabolites, and glucose and insulin metabolism as assessed by a frequently sampled intravenous glucose tolerance test.RESULTSChronic mirabegron therapy increased BAT metabolic activity. Whole-body REE was higher, without changes in body weight or composition. Additionally, there were elevations in plasma levels of the beneficial lipoprotein biomarkers HDL and ApoA1, as well as total bile acids. Adiponectin, a WAT-derived hormone that has antidiabetic and antiinflammatory capabilities, increased with acute treatment and was 35% higher upon completion of the study. Finally, an intravenous glucose tolerance test revealed higher insulin sensitivity, glucose effectiveness, and insulin secretion.CONCLUSIONThese findings indicate that human BAT metabolic activity can be increased after chronic pharmacological stimulation with mirabegron and support the investigation of β3-AR agonists as a treatment for metabolic disease.TRIAL REGISTRATIONClinicaltrials.gov NCT03049462.FUNDINGThis work was supported by grants from the Intramural Research Program of the NIDDK, NIH (DK075112, DK075116, DK071013, and DK071014).

The sympathomimetic agonist mirabegron did not lower JAK2-V617F allele burden, but restored nestin-positive cells and reduced reticulin fibrosis in patients with myeloproliferative neoplasms: results of phase II study SAKK 33/14

The β-3 sympathomimetic agonist BRL37344 restored nestin-positive cells within the stem cell niche, and thereby normalized blood counts and improved myelofibrosis in a mouse model of JAK2-V617F-positive myeloproliferative neoplasms. We therefore tested the effectiveness of mirabegron, a β-3 sympathomimetic agonist, in a phase II trial including 39 JAK2-V617F-positive patients with myeloproliferative neoplasms and a mutant allele burden more than 20%. Treatment consisted of mirabegron 50 mg daily for 24 weeks. The primary end point was reduction of JAK2-V617F allele burden of 50% or over, but this was not reached in any of the patients. One patient achieved a 25% reduction in JAK2-V617F allele burden by 24 weeks. A small subgroup of patients showed hematologic improvement. As a side study, bone marrow biopsies were evaluated in 20 patients. We found an increase in the nestin+ cells from a median of 1.09 (interquartile range 0.38-3.27)/mm2 to 3.95 (interquartile range 1.98-8.79)/mm2 (P<0.0001) and a slight decrease of reticulin fibrosis from a median grade of 1.0 (interquartile range 0-3) to 0.5 (interquartile range 0-2) (P=0.01) between start and end of mirabegron treatment. Despite the fact that the primary end point of reducing JAK2-V617F allele burden was not reached, the observed effects on nestin+ mesenchymal stem cells and reticulin fibrosis is encouraging, and shows that mirabegron can modify the microenvironment where the JAK2-mutant stem cells are maintained. (Registered at clinicaltrials.gov identifier: 02311569).

Efficacy and safety of mirabegron for the treatment of neurogenic detrusor overactivity-Prospective, randomized, double-blind, placebo-controlled study

AIMS

To assess the efficacy and safety of mirabegron in the treatment of neurogenic detrusor overactivity.

METHODS

This prospective, multicenter, randomized, double-blind, placebo-controlled study was conducted in three tertiary centers, and included 78 patients suffering from spinal cord injury or multiple sclerosis. Patients were randomized for Mirabegron 50 mg (Group A) or placebo (Group B). Urodynamic parameters, the 24 h pad-weight test, and patient-reported outcomes were assessed. Safety assessments included monitoring the incidence and severity of adverse events. Changes in time and differences between groups were assessed with nonparametric Kruskal-Wallis one-way analysis of variance; P ≤ 0.05 was considered statistically significant.

RESULTS

In total, 66 patients were eligible for inclusion in the final analysis. There was a significant increase of volume at the first detrusor contraction (P = 0.00047) and an improvement in bladder compliance (P = 0.0041) in the mirabegron group compared with the placebo-treated group, whereas the increase in cystometric capacity did not reach statistical significance (P = 0.061). There was a clear tendency to reduced urine leakage (P = 0.056) in Group A. There were significant changes in all the patient-reported outcomes, favoring the mirabegron group. The incidence of drug-related adverse events was 3.13%.

CONCLUSIONS

Mirabegron (50 mg) improved both urodynamic variables and patient-reported outcomes in patients with NDO. The treatment was tolerated well.

[The place of mirabegron in clinical practice]

Currently, a wide range of different drugs is available for te management of overactive bladder. This creates problems when it comes to drug selection and personalized care for each patient. Mirabegron is the only 3-adrenomimetic agent for the treatment of urinary disorders, which, after careful long-term multi-center randomized trials, has been approved for use in Europe and North America. Mirabegron has proven to be very effective in patients who had previously received anticholinergic drugs and discontinued them because of the insufficient therapeutic effect or pronounced adverse reactions. However, the question of using Mirabegron as a first-line treatment for overactive bladder and the existing limitations in its administration in clinical urology practice remains open.

Cardiovascular safety in refractory incontinent patients with overactive bladder receiving add-on mirabegron therapy to solifenacin (BESIDE)

AIMS/OBJECTIVES

In the BESIDE study, combination therapy (antimuscarinic [solifenacin] and β₃ -adrenoceptor agonist [mirabegron]) improved efficacy over solifenacin monotherapy without exacerbating anticholinergic side effects in overactive bladder (OAB) patients; however, a potential synergistic effect on the cardiovascular (CV) system requires investigation.

METHODS

OAB patients remaining incontinent despite daily solifenacin 5 mg during 4-week single-blind run-in, were randomised 1:1:1 to double-blind daily combination (solifenacin 5 mg/mirabegron 25 mg, increasing to 50 mg after week 4), solifenacin 5 or 10 mg for 12 weeks. CV safety assessments included frequency of CV-related treatment-emergent adverse events (TEAEs), change from baseline in vital signs (systolic blood pressure [SBP], diastolic blood pressure [DBP], pulse rate) and electrocardiogram (ECG) parameters.

RESULTS

The frequency of hypertension, tachycardia and ECG QT prolongation, respectively, was low and comparable across combination (1.1%, 0.3%, 0.1%), solifenacin 5 mg (0.7%, 0.1%, 0.1%), and solifenacin 10 mg groups (0.8%, 0%, 0.1%). Adjusted mean (SE) change from baseline to end of treatment (EoT) in SBP, DBP, and pulse rate with combination (0.07 mm Hg [0.38], -0.35 mm Hg [0.26], 0.47 bpm [0.28]), solifenacin 5 mg (-0.93 mm Hg [0.38], -0.45 mm Hg [0.26], 0.43 bpm [0.28]) and solifenacin 10 mg (-1.28 mm Hg [0.38], -0.48 mm Hg [0.26], 0.27 bpm [0.28]) was generally comparable, with the exception of a mean treatment difference of ~1 mm Hg in SBP between combination and solifenacin monotherapy; SBP was unchanged with combination and decreased with solifenacin monotherapy. Mean changes from baseline to EoT in ECG parameters were generally similar across treatment groups, except for QT interval corrected using Fridericia's formula, which was higher with solifenacin 10 mg (3.30 mseconds) vs. combination (0.49 mseconds) and solifenacin 5 mg (0.77 mseconds).

CONCLUSION

The comparable frequency of CV-related TEAEs, changes in vital signs and ECG parameters indicates no synergistic effect on CV safety outcomes when mirabegron and solifenacin are combined.

Pharmacokinetic drug interaction study between overactive bladder drugs mirabegron and tolterodine in Japanese healthy postmenopausal females

Mirabegron, the first selective β₃-adrenoceptor agonist for the treatment of overactive bladder (OAB), inhibits cytochrome P450 isozyme CYP2D6. This study was performed in Japanese healthy postmenopausal female volunteers to assess any pharmacokinetic drug interaction between mirabegron and tolterodine, another OAB drug and a sensitive substrate of CYP2D6. Tolterodine 4 mg was orally administered from Days 1-7 and co-administered with mirabegron 50 mg from Days 8-14. Mirabegron 50 mg increased maximum concentration (C_max) and area under the concentration-time curve from zero to 24 h after dosing (AUC_24h) of tolterodine by 2.06-fold (90% confidence interval [CI] 1.81, 2.34) and 1.86-fold (90% CI 1.60, 2.16), respectively, and increased C_max and AUC_24h of the metabolite 5-hydroxymethyl tolterodine by 1.36-fold (90% CI 1.26, 1.47) and 1.25-fold (90% CI 1.15, 1.37), respectively. This suggested a weak pharmacokinetic drug interaction between mirabegron and tolterodine. Mean change from baseline of Fridericia's QT correction formula (ΔQTcF) was slightly higher on Day 14 than on Day 7. No subject had QTcF >480 msec or ΔQTcF >60 msec. All the treatment-emergent adverse events were mild. Mirabegron 50 mg was considered to be safe and well tolerated when coadministered with tolterodine 4 mg in healthy postmenopausal female volunteers.

Alterations in juvenile diploid and triploid African catfish skin gelatin yield and amino acid composition: Effects of chlorpyrifos and butachlor exposures

Skin is a major by-product of the fisheries and aquaculture industries and is a valuable source of gelatin. This study examined the effect of triploidization on gelatin yield and proximate composition of the skin of African catfish (Clarias gariepinus). We further investigated the effects of two commonly used pesticides, chlorpyrifos (CPF) and butachlor (BUC), on the skin gelatin yield and amino acid composition in juvenile full-sibling diploid and triploid African catfish. In two separate experiments, diploid and triploid C. gariepinus were exposed for 21 days to graded CPF [mean measured: 10, 16, or 31 μg/L] or BUC concentrations [Mean measured: 22, 44, or 60 μg/L]. No differences in skin gelatin yield, amino acid or proximate compositions were observed between diploid and triploid control groups. None of the pesticide treatments affected the measured parameters in diploid fish. In triploids, however, gelatin yield was affected by CPF treatments while amino acid composition remained unchanged. Butachlor treatments did not alter any of the measured variables in triploid fish. To our knowledge, this study is the first to investigate changes in the skin gelatin yield and amino acid composition in any animal as a response to polyploidization and/or contaminant exposure.

mirabegron (BETMIGA⁰). Poorly effective in urge urinary incontinence

Mirabegron interacts with many other drugs via cytochrome P450 isoenzymes. It also has additive adverse effects, in particular cardiac disorders, when combined with antimuscarinic drugs. In view of animal data and the lack of clinical data, mirabegron should not be used by women who are or may be pregnant. In practice, drugs have little value in treating urinary urgency attributed to "overactive bladder". The risk of adverse drug reactions is rarely justified, even when the disorder is severe. Antimuscarinic disorders, such as dry mouth, are less frequent with mirabegron than with antimuscarinic drugs. Like antimuscarinic drugs, mirabegron can cause cardiac arrhythmias, especially tachycardia. Mirabegron may also cause a dose-dependent increase in blood pressure. Other adverse effects include rare cases of kidney stones and rare but sometimes serious skin reactions. When a treatable cause of urinary urgency with incontinence has been ruled out and non-drug measures have failed, recourse to an antimuscarinic drug is slightly effective but exposes patients to numerous, potentially severe adverse effects. Mirabegron (Betmiga⁰, Astellas Pharma), a beta-3 adrenergic receptor agonist, is authorised for use in this setting in the European Union. Clinical evaluation of mirabegron is mainly based on five randomised, double-blind trials versus antimuscarinic drugs, lasting 3 to 12 months and including about 8000 patients with urinary urgency. Mirabegron and the antimuscarinic comparators were similarly effective, even after antimuscarinic drug failure. A meta-analysis of four placebo-controlled trials including about 3500 patients suggested that mirabegron was poorly effective: on average, treatment prevented one episode of urinary incontinence every 2 days.

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

BACKGROUND

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

[Persistence in the treatment of overactive bladder (OAB) with Mirabegron in a multicentre clinical study]

OBJECTIVE

The objective of this monitoring was to evaluate persistence in the treatment of patients with overactive bladder syndrome (OAB) using mirabegron.

DESIGN

Prospective clinical study.

SETTING

10 gynecological and urological departments in CZE.

MATERIALS AND METHODS

This is an analysis of a prospective, multicenter monitoring which started in May 2014 and will continue for 1 year. This monitoring included patients 18 years old who have had symptoms of OAB for minimum 3 months. The patient check-up was performed 6 months (±2 weeks) after the first visit. The dosage of mirabegron was 50 mg per day. For the evaluation the treatment efficacy we employed the TS-VAS and PPBC. During the check-up it was ascertained how many patients discontinued the treatment with mirabegron, and reasons for this interruption were established. The statistics were calculated using the software SPSS 20.0.

RESULTS

A prospective monitoring was performed on 206 patients. Their mean age was 62.8 years (range 23-89); mean body mass index for the whole group of patients was 27.3. At the check-up 6 months post-initiation of treatment it emerged that 55/206 (27%) patiens had discontinued the treatment. The reasons for discontinuation of treatment were: 24/55 (43%) insufficient treatment efficacy, 29/55 (53%) other reasons (the main reasons here were hospitalisation, surgery, gravidity) and 2/55 discontinued therapy because of side effects. The side effects were tachycardia, eye irritation, lower abdominal pain and vasculitis, and they were mild in nature. The termination of the study was 7/28 (25%) in the group of patients without previous treatment before mirabegron. Discontinuation of the treatment in the group of patients with previous anticholinergic treatment was 48/178 (27%). At the evaluation of the efficacy of the treatment during the check-up 6 months after initiation of treatment the mean TS-VAS was 77.5, a decrease of the scale of bothers evaluated by PPBC before treatment from a mean value of 3.56 to a value of 1.77.

CONCLUSIONS

Our hypothesis, that persistence in treat-ment with mirabegron would be relatively high due to reduced side effects and better cure effect, was confirmed, and this is the reason for higher rates of persistence in the treatment at 6 months check-up (73%).

[MIRABEGRON--A NEW DRUG FOR TREATMENT OF OVERACTIVE BLADDER]

Mirabegron is the first drug in a new class of oral therapy for overactive bladder (OAB). It is a beta-3 adrenergic agonist, a class of drugs for the first time used for the treatment of urination disorders. Recently, following many years of rigorous multicenter randomized trials mirabegron has been approved for use in Europe and North America. The clinical indication for mirabegron is overactive bladder with symptoms of urge urinary incontinence, urgency, and urinary frequency and other storage symptoms in both men and women. Mirabegron is used in primary patients, or in patients who previously were unsuccessfully treated with anticholinergics. The drug has a good safety profile and causes no side effects typical of anticholinergics.

Myopathy during treatment with the antianginal drug ranolazine

Ranolazine is a medication indicated for treatment of chronic angina and is a partial inhibitor of the fatty acid β-oxidation. We present an adult patient who developed subacute progressive muscle weakness and exercise-induced myalgia, soon after increasing the daily dose of ranolazine, in the setting of therapy with simvastatin. CK persisted normal throughout the duration of the weakness and muscle biopsy showed a lipid storage myopathy for which no underlying genetic defect was identified. Discontinuation of both drugs resulted in clinical improvement. Although simvastatin may have contributed to the myopathy, the temporal relation between the increase in ranolazine dose and the onset of the weakness would favor ranolazine as major culprit for the weakness.

Ranolazine refractory angina registry: 1-year results

Patients with refractory angina (RA) have limited therapeutic options and significant limitations in their quality of life. Ranolazine is approved for patients with chronic stable angina but has not been studied in patients with RA. The Ranolazine Refractory Angina Registry was designed to evaluate the safety, tolerability, and effectiveness in RA patients. In a dedicated RA clinic using an extensive prospective database, 100 patients were enrolled. Angina class, medications, major adverse cardiac events including death, myocardial infarction, and revascularization were obtained at 1, 6, and 12 months. Overall 43% of patients had a ≥2 class improvement in angina. At 1 year, 57% patients remained on ranolazine (91.2%; 500 mg BID), including 58% with a ≥2 class improvement in angina. Reasons for discontinuation included: side effects (n = 16), major adverse cardiac events (n = 10), cost (n = 5), ineffective (n = 6), cost and ineffective (n = 3), and unknown (n = 3). In conclusion, ranolazine is an effective antianginal therapy in patients with RA; still at 1 year only 57% of patients remained on ranolazine because of side effects, suboptimal effectiveness, cost, or progression of disease.

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.

Update on ranolazine in the management of angina

Mortality rates attributable to coronary heart disease have declined in recent years, possibly related to changes in clinical presentation patterns and use of proven secondary prevention strategies. Chronic stable angina (CSA) remains prevalent, and the goal of treatment is control of symptoms and reduction in cardiovascular events. Ranolazine is a selective inhibitor of the late sodium current in myocytes with anti-ischemic and metabolic properties. It was approved by the US Food and Drug Administration in 2006 for use in patients with CSA. Multiple, randomized, placebo-controlled trials have shown that ranolazine improves functional capacity and decreases anginal episodes in CSA patients, despite a lack of a significant hemodynamic effect. Ranolazine did not improve cardiovascular mortality or affect incidence of myocardial infarction in the MERLIN (Metabolic Efficiency with Ranolazine for Less Ischemia in Non-ST-Elevation Acute Coronary Syndrome)-TIMI (Thrombolysis In Myocardial Infarction) 36 trial, but significantly decreased the incidence of recurrent angina. More recently, ranolazine has been shown to have beneficial and potent antiarrhythmic effects, both on supraventricular and ventricular tachyarrhythmias, largely due to its inhibition of the late sodium current. Randomized controlled trials testing these effects are underway. Lastly, ranolazine appears to be cost-effective due to its ability to decrease angina-related hospitalizations and improve quality of life.

Slow junctional rhythm, QTc prolongation and transient torsades de-pointes following combined use of Ivabradine, Diltiazem and Ranolazine

A case of unstable angina developed slow junctional rhythm with QTc prolongation and transient Torsades de pointes following simultaneous use of Ivabradine, Diltiazem and Ranolazine. Effect of Diltiazem on hepatic isoenzyme CYP 3A could be responsible. Such a combination should be avoided.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSION

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

New drug update: 2012

Five new drugs that are used for medical problems often experienced by the elderly have been selected for consideration in this review. The uses and most important properties of these agents are considered, and a rating for each new drug is determined. The rating is based on a comparison of the new drug with related drugs already marketed. Advantages, disadvantages, and other important information regarding the new drug are identified and used as the basis for determining the rating.

Ranolazine-induced myopathy in a patient on chronic statin therapy

We present a case demonstrating clinical, electrophysiological, serological, and radiological evidence of a myopathy induced by ranolazine, in a patient otherwise asymptomatic on chronic statin therapy. The patient developed proximal weakness, serum creatine kinase levels of 1875 U/L, electromyography with muscle membrane instability and small short-duration motor unit potentials, and magnetic resonance imaging evidence of muscle edema. The manifestations began within one week of initiation of ranolazine and improved within days after discontinuation. Ranolazine is a weak inhibitor of CYP3A4 known to increase the serum level of simvastatin and its active metabolite 2-fold. We postulate that the addition of ranolazine to a medical regimen that included atorvastatin induced a myoncecrotic myopathy.

Tolerability and pharmacokinetics of ranolazine following single and multiple sustained-release doses in Chinese healthy adult volunteers: a randomized, open-label, Latin square design, phase I study

BACKGROUND AND OBJECTIVES

Ranolazine was approved by the US Food and Drug Administration in January 2006 for the treatment of chronic angina pectoris, and is the first approved agent from a new class of anti-anginal drugs in almost 25 years. The primary objective of this study was to determine the concentration of ranolazine in human plasma using the liquid chromatography/tandem mass spectrometry (LC-MS/MS) method and to compare the pharmacokinetic properties of ranolazine after administration of single and multiple doses of ranolazine in healthy Chinese adult volunteers.

METHODS

A randomized, open-label, single- and multiple-dose study design was used in the study. Subjects were randomized to receive a single dose of 500, 1,000, or 1,500 mg of ranolazine. Those who received the single dose continued on to the multiple-dose phase and received 500 mg twice daily for 7 days. In the single-dose phase, blood samples were collected from 0 to 48 h after drug administration. In the multiple-dose phase, samples were obtained before drug administration at 8:00 am and 8:00 pm on days 6 and 7 to determine the minimum steady-state plasma concentration (C(min,ss)) of ranolazine; on day 8, samples were collected from 0 to 48 h after drug administration. All values were expressed as means (standard deviations [SDs]). Adverse events (AEs) were monitored throughout the study via subject interview, vital signs, and blood sampling.

RESULTS

The LC-MS/MS method was developed and validated. Twelve Chinese subjects (six men, six women) were enrolled in the single-dose phase of the pharmacokinetic study. The mean (SD) age of the subjects was 24.7 (1.6) years; their mean (SD) weight was 61.3 (6.4) kg, their mean (SD) height was 165.7 (4.5) cm, and their mean (SD) body mass index was 21.6 (6.6) kg/m(2). The main pharmacokinetic parameters [mean (SD)] for ranolazine after administration of a single oral dose of 500, 1,000, and 1,500 mg were as follows: maximum plasma concentration (C(max)) 741.5 (253.0), 1,355.0 (502.0), and 2,328.7 (890.5) ng/mL, respectively; area under the concentration-time curve from time zero to 48 h (AUC(48)) 9,071.9 (3,400.0), 16,573.5 (6,806.2), and 29,324.5 (10,857.2) ng·h/mL; AUC from time zero extrapolated to infinity (AUC(∞)) 9,826.7 (3,152.0), 16,882.4 (6,790.8), and 29,923.5 (10,706.3) ng·h/mL; time to reach C(max) (t(max)) 5.3 (1.4), 4.2 (1.2), and 5.9 (2.8) h; elimination half-life (t(½)) 6.4 (3.3), 6.4 (3.5), and 6.7 (4.3) h. Mean (SD) values for the main pharmacokinetic parameters for ranolazine after administration of multiple doses were as follows: steady-state C(max) (C(max,ss)) 1,732.9 (547.3) ng/mL; C(min,ss) 838.1 (429.8) ng/mL; steady-state AUC at time t (AUC(ss,(t))) 14,655.5 (5,624.2) ng·h/mL; average steady-state plasma drug concentration during multiple-dose administration (C(av,ss)) 1,221.3 (468.7) ng/mL; t(max) 3.46 (1.48) h; t(½) 6.28 (2.48) h.

CONCLUSION

In this group of healthy Chinese subjects, AUC and C(max) increased proportionally with the dose, whereas t(½) was independent of the dose. The pharmacokinetic properties of ranolazine were linear after administration of single oral doses of 500 to 1,500 mg. Compared with the pharmacokinetic parameters of the subjects who received a single dose, those who received multiple doses (twice daily) of ranolazine had a larger AUC from time zero to the time of the last measurable concentration (AUC(last)), AUC(∞), C(max), and apparent total body clearance of drug from plasma after oral administration (CL/F), and shorter t(max) (all p < 0.05). Furthermore, some of the main pharmacokinetic parameters of ranolazine may reflect ethnic differences. This dosage was generally well tolerated by all the subjects.

β3-Adrenoceptor agonist mirabegron is effective for overactive bladder that is unresponsive to antimuscarinic treatment or is related to benign prostatic hyperplasia in men

PURPOSE

To investigate the safety and efficacy of mirabegron for patients with overactive bladder (OAB) that is unresponsive to antimuscarinic agents or is related to benign prostatic hyperplasia (BPH).

METHODS

Fifty-two newly diagnosed OAB patients (M group) and 45 patients with OAB that was unresponsive to antimuscarinics (S group) received mirabegron 50 mg once daily and were evaluated by OAB symptom score (OABSS), IPSS-QOL index, and IPSS at the time of baseline, 4 and 8 weeks. Newly diagnosed OAB patients treated with antimuscarinic agents were compared as controls.

RESULTS

Mirabegron was effective for 85.2 % in M group. Significant improvements were seen in each domain of OABSS, and there was no significant difference with antimuscarinic therapy. Mirabegron was efficacious for 61.6 % of S group, and significant decreases of OABSS and IPSS-QOL index were observed. Significant improvements were also seen in voiding symptoms in men. Post-void residual urine volumes before and after treatment were 32.1 and 34.8 ml, and 26.2 and 31.3 ml in M and S group, respectively, and there was no significant difference. The incidence of adverse events was 8.4 %, although none were serious, and the patients recovered spontaneously after mirabegron was discontinued.

CONCLUSION

The present study suggests mirabegron is as effective as antimuscarinics for OAB. It improves OAB symptoms in patients with OAB for which antimuscarinic agents are insufficient. This study revealed that mirabegron improves not only OAB symptoms related to BPH, but also voiding symptoms in men. Low and mild incidences of side effects support the safe utility of mirabegron.

[New developments in the antiarrhythmic therapy of atrial fibrillation]

Atrial fibrillation, which is associated with a worsening of congestive heart failure symptoms, an increased rate of stoke, and increased mortality, is still difficult to treat. New therapies must not only increase effectiveness, but also have to have an improved safety profile, in order to avoid sodium channel block in the ventricle of older patients with atrial fibrillation, and also prevent electrical and morphological remodeling. Dronedarone is less effective compared to amiodarone, but has a better side effect profile which leads to fewer discontinuations of treatment. The atrial ion channels are specifically blocked by a number of prospective antiarrhythmic substances. The most advanced is the testing of vernakalant (RSD1235), which primarily suppresses the I(Kur) current. Ranolazine is a new antianginal substance which influences the atrial ion channels and leads to a significant reduction of atrial and more specifically ventricular tachyarrhythmias. A number of other drugs are in development. They will lead to a better understanding of which form of atrial fibrillation can be best treated with which antiarrhythmic agent.

Mirabegron, a β₃-adrenoceptor agonist for the potential treatment of urinary frequency, urinary incontinence or urgency associated with overactive bladder

Mirabegron (YM-178), currently in development by Astellas Pharma Inc, is an orally active β₃-adrenoceptor (AR) agonist for the potential symptomatic treatment of overactive bladder (OAB). Mirabegron demonstrates nanomolar EC50 values against the human β₃-AR in biochemical assays with potent selectivity over the β₁- and β₂-ARs. Originally developed as a treatment for diabetes, the development of mirabegron was later refocused to OAB. Cystometric experiments in rats reported a reduction in resting intravesical pressure and contraction frequency in anesthetized rats, without any effect on the amplitude of micturition contraction. Mirabegron also reduced non-micturition bladder contractions in an awake rat model of bladder outlet obstruction. Top-line results from clinical trials to date indicate that mirabegron has been well tolerated with significant efficacy in reducing the number of incontinence episodes and mean micturition frequency in patients. Evidence of cytochrome P450 (CYP)2D6 inhibition in clinical trials highlighted a concern for pharmacokinetic interaction with other drugs that are CYP2D6 substrates, as confirmed by a rise in the pharmacokinetic parameters of desipramine with concomitant administration of mirabegron. Mirabegron exhibits a novel mode of action in targeting the β₃-AR for bladder relaxation, and the studies and trials conducted to date suggest mirabegron as a promising new treatment in the management of OAB symptoms, such as increased urinary urgency and frequency, and urgency incontinence.

At the dawn of a new era in treating angina pectoris, or just another antianginal drug? Some considerations about ranolazine

Ranolazine is a new compound that has been approved by the FDA for use in patients who have chronic stable angina refractory to conventional antianginal medications. Ranolazine proved to be effective also as monotherapy in patients with stable angina and as part of a combination regimen. This review is inspired by the presentation that legendary figures in contemporary cardiology, such as Braunwald, Komajda and Camm made recently at the Congress of the European Society of Cardiology held in Stockholm, Sweden, last September.

Ranolazine: a new approach to treating an old problem

Chronic angina pectoris affects millions of patients every year. During the past 2 decades, advances in medical therapy have led to substantial reductions in the symptoms of angina. Nonetheless, many patients continue to experience persistent angina that causes debilitating symptoms and lifestyle changes. Moreover, many current therapeutic agents cause side effects that can induce substantial morbidity on their own. In major clinical trials, the drug ranolazine has been shown to bring symptomatic relief to large numbers of patients who have chronic angina. Herein, we review the physiology of the sodium channel; the pharmacology of ranolazine; clinical trials that support use of the drug; recent evidence about ranolazine's therapeutic effect on diastolic heart failure, glycemic control, and atrial fibrillation and other arrhythmias; officially approved clinical indications; and avenues of future study.

[Ranolazine--new treatment of chronic stable angina pectoris]

Ranolazine sustained-release tablets were recently approved in the EU for chronic stable angina as add-on therapy when symptoms are not controlled with first-line agents. The mechanism of action is thought to involve inhibition of late sodium influx in the heart, which can reduce abnormalities of contractility and repolarisation associated with ischaemia. Ranolazine increases the exercise capacity, reduces angina, and diminishes the use of nitroglycerine. The drug has an excellent safety profile and may be a valuable addition to the treatment of chronic stable angina.

Ranolazine: new drug. Stable angina: not worth the risk

(1) Betablockers such as atenolol are the first-line symptomatic treatment for stable angina. Calcium channel blockers such as verapamil and amlodipine are second-line alternatives; (2) Ranolazine is now authorized for symptomatic adjuvant treatment of angina in patients who are poorly controlled by a betablocker and/or a calcium channel blocker. Its mechanism of action is poorly understood; (3) In two randomised double-blind trials in respectively 565 and 823 patients treated for 7 and 12 weeks, ranolazine (500 mg to 1000 mg twice a day), added to ongoing amlodipine therapy only provided a limited benefit, preventing less than one angina attack per week; (4) Comparative trials failed to show whether ranolazine has a clear-cut impact on mortality; (5) Ranolazine prolongs the QT interval in a dose-dependent manner and thus exposes patients to the risk of torsades de pointes. It is also associated with gastrointestinal disorders (constipation, nausea, vomiting) and dizziness; (6) Ranolazine is metabolised by the cytochrome P450 isoenzymes CYP 3A4 and CYP 2D6 and is also a P-glycoprotein substrate. There is therefore a high risk of pharmacokinetic interactions. There is also a risk of pharmacodynamic interactions with drugs that prolong the QT interval; (7) In practice, the efficacy of ranolazine in the prevention of angina attacks does not outweigh the risk of severe adverse effects.

Multiple drug interactions in a renal transplant patient leading to simvastatin-induced rhabdomyolysis: a case report

Rhabdomyolysis, a syndrome characterized by muscle necrosis with release of toxic intracellular muscle constituents, can be a potentially fatal side effect of medical therapy. Here I report a patient with a 12-year history of simvastatin use who presented with rhabdomyolysis. He had a renal transplant and has been on a stable dose of cyclosporine for the past year. Recent medication changes were the addition of ranolazine, carvedilol, and diltiazem about two months prior to the episode of rhabdomyolysis. Discontinuation of the ranolazine, diltiazem, and simvastatin resulted in prompt resolution of the episode. It is suggested that these medications, acting in concert with cyclosporine, altered the metabolism of simvastatin, causing the episode of rhabdomyolysis. Clinicians should be alert to the possibility of multiple drug interactions causing rhabdomyolysis.

Ranolazine for chronic stable angina

Ranolazine is a new and unique antianginal drug that has been approved for the treatment of chronic stable angina pectoris. The drug is administered as a sustained-release formulation. Although the drug's mechanism of action has not been fully elucidated, current thinking is that ranolazine, a selective inhibitor of late sodium influx, attenuates the abnormalities of ventricular repolarisation and contractility associated with ischaemia. Three randomised trials have shown efficacy for ranolazine in increasing exercise testing or reducing anginal episodes or use of glyceryl trinitrate. Side-effects include dizziness, constipation, nausea, and the potential for prolongation of the QT(c) interval. Ranolazine seems to be a safe addition to current traditional drugs for chronic stable angina, especially in aggressive multidrug regimens.

The cardiac persistent sodium current: an appealing therapeutic target?

The sodium current in the heart is not a single current with a mono-exponential decay but rather a mixture of currents with different kinetics. It is not clear whether these arise from distinct populations of channels, or from modulation of a single population. A very slowly inactivating component, [(INa(P))] I(Na(P)) is usually about 1% of the size of the peak transient current [I(Na(T))], but is enhanced by hypoxia. It contributes to Na(+) loading and cellular damage in ischaemia and re-perfusion, and perhaps to ischaemic arrhythmias. Class I antiarrhythmic agents such as flecainide, lidocaine and mexiletine generally block I(NA(P)) more potently than block of I(Na(T)) and have been used clinically to treat LQT3 syndrome, which arises because mutations in SCN5A produce defective inactivation of the cardiac sodium channel. The same approach may be useful in some pathological situations, such as ischaemic arrhythmias or diastolic dysfunction, and newer agents are being developed with this goal. For example, ranolazine blocks I(Na(P)) about 10 times more potently than I(Na(T)) and has shown promise in the treatment of angina. Alternatively, the combination of I(Na(P)) block with K(+) channel block may provide protection from the induction of Torsades de Pointe when these agents are used to treat atrial arrhythmias (eg Vernakalant). In all of these scenarios, an understanding of the role of I(Na(P)) in cardiac pathophysiology, the mechanisms by which it may affect cardiac electrophysiology and the potential side effects of blocking I(Na(P)) in the heart and elsewhere will become increasingly important.

Effect of Ranolazine, an Antianginal Agent With Novel Electrophysiological Properties, on the Incidence of Arrhythmias in Patients With Non–ST-Segment–Elevation Acute Coronary Syndrome

Background— Ranolazine, a piperazine derivative, reduces ischemia via inhibition of the late phase of the inward sodium current (late I Na ) during cardiac repolarization, with a consequent reduction in intracellular sodium and calcium overload. Increased intracellular calcium leads to both mechanical dysfunction and electric instability. Ranolazine reduces proarrhythmic substrate and triggers such as early afterdepolarization in experimental models. However, the potential antiarrhythmic actions of ranolazine have yet to be demonstrated in humans.

Methods and Results— The Metabolic Efficiency With Ranolazine for Less Ischemia in Non–ST-Elevation Acute Coronary Syndrome (MERLIN)–Thrombolysis in Myocardial Infarction (TIMI) 36 (MERLIN-TIMI 36) trial randomized 6560 patients hospitalized with a non–ST-elevation acute coronary syndrome to ranolazine or placebo in addition to standard therapy. Continuous ECG (Holter) recording was performed for the first 7 days after randomization. A prespecified set of arrhythmias were evaluated by a core laboratory blinded to treatment and outcomes. Of the 6560 patients in MERLIN-TIMI 36, 6351 (97%) had continuous ECG recordings that could be evaluated for arrhythmia analysis. Treatment with ranolazine resulted in significantly lower incidences of arrhythmias. Specifically, fewer patients had an episode of ventricular tachycardia lasting ≥8 beats (166 [5.3%] versus 265 [8.3%]; P <0.001), supraventricular tachycardia (1413 [44.7%] versus 1752 [55.0%]; P <0.001), or new-onset atrial fibrillation (55 [1.7%] versus 75 [2.4%]; P =0.08). In addition, pauses ≥3 seconds were less frequent with ranolazine (97 [3.1%] versus 136 [4.3%]; P =0.01).

Conclusions— Ranolazine, an inhibitor of late I Na , appears to have antiarrhythmic effects as assessed by continuous ECG monitoring of patients in the first week after admission for acute coronary syndrome. Studies specifically designed to evaluate the potential role of ranolazine as an antiarrhythmic agent are warranted.