Evaluation of the Pharmacokinetic Interaction Between the β3-Adrenoceptor Agonist Mirabegron and the Muscarinic Receptor Antagonist Solifenacin In Healthy Subjects

Efficacy and Safety of Mirabegron Add-on Therapy After Failure With Solifenacin in Multiple Sclerosis Patients With Overactive Bladder: A Pilot Study

OBJECTIVES

Multiple sclerosis (MS) is a chronic neuroinflammatory and neurodegenerative progressive disease of central nervous system that mostly affects young adults. (1) Because of involvement of spinal cord and brain, lower urinary dysfunction symptoms are commonly encountered. MS patients mostly show overactive bladder symptoms like urgency, frequent daytime urination, and urgency incontinence. Among MS patients, antimuscarinic therapy is the first-line treatment with overactive bladder symptoms as well as in general population yet 30% of the patients show insufficient improvement or intolerance to the treatment (2). In our study, our aim is to evaluate the efficacy and safety of mirabegron add-on treatment in MS patients after inadequate response to antimuscarinic monotherapy.

METHODS

University of Kyrenia and Dr Burhan Nalbantoglu State hospital's databases were screened for the study. Seventy patients who were residents diagnosed with MS according to McDonald criteria were questioned. Among these patients, a total of 22 of them were included in the study. Inclusion criteria was at least 3 years of MS diagnosis, score of <6 at Expanded Disability Status Scale, and a score of ≥3 at Overactive Bladder Symptom Score Scale.

RESULTS

Among selected patients, 10 mg solifenacin treatment was daily started and followed for 4 weeks. Mirabegron add-on treatment was initiated to the 11 patient who had inadequate improvement in overactive bladder symptom score. After mirabegron add-on treatment among 11 patient, there was a sufficient improvement in overactive bladder symptom score ( P < 0.008).

CONCLUSIONS

In our study, we have found that antimuscarinic and mirabegron combination causes improved efficacy for overactive bladder in MS population.

Physiologically Based Pharmacokinetic Modeling Suggests Limited Drug-Drug Interaction for Fesoterodine When Coadministered With Mirabegron

5-Hydroxymethyl tolterodine (5-HMT; the active fesoterodine metabolite) is metabolized via the cytochrome P450 (CYP) 2D6 and CYP3A pathways. Mirabegron is a moderate CYP2D6 inhibitor and weak CYP3A inhibitor. Potential drug-drug interactions (DDIs) following coadministration of these 2 overactive bladder treatments were estimated using physiologically based pharmacokinetic models, developed and verified by comparing predicted and observed pharmacokinetic profiles from clinical studies. Models predicted and verified mirabegron and desipramine (CYP2D6 substrate) and 5-HMT and ketoconazole (strong CYP3A inhibitor) DDIs. Mirabegron model-predicted mean steady-state AUC and C_max were within 11% of clinical observations. The predicted versus observed geometric mean ratio (GMR) of AUC_inf for CYP2D6 substrates desipramine and metoprolol coadministered with mirabegron 100 or 160 mg once daily were 3.47 versus 3.41 and 2.97 versus 3.29, respectively, indicating that the mirabegron model can be used to predict clinical CYP2D6 inhibition. 5-HMT fractional clearance by CYP3A and CYP2D6 was verified from clinical DDI studies with a potent CYP3A4 inhibitor (ketoconazole) and inducer (rifampicin) in CYP2D6 extensive and poor metabolizers and with a moderate CYP3A inhibitor (fluconazole) in healthy volunteers. 5-HMT AUC_inf and C_max GMRs for fesoterodine DDIs were all predicted within 1.26-fold of clinical observation, providing verification for the fesoterodine substrate model. The predicted changes in 5-HMT AUC_inf and C_max ratios for 8 mg fesoterodine when coadministered with 50 mg mirabegron were 1.22-fold and 1.17-fold, respectively, relative to 8 mg fesoterodine given alone. This modest increase in 5-HMT exposures by approximately 20% is considered clinically insignificant and would not require fesoterodine dose adjustment when coadministered with mirabegron within approved daily-dose ranges.

Long-term Safety and Efficacy of Mirabegron and Solifenacin in Combination Compared with Monotherapy in Patients with Overactive Bladder: A Randomised, Multicentre Phase 3 Study (SYNERGY II)

BACKGROUND

The long-term potential of solifenacin and mirabegron combination treatment for patients with overactive bladder (OAB) has not been previously assessed.

OBJECTIVES

To evaluate the safety and efficacy of solifenacin succinate 5mg plus mirabegron 50mg tablets (combination treatment) versus solifenacin or mirabegron monotherapy in patients with OAB over 12 mo.

DESIGN, SETTING, AND PARTICIPANTS

Randomised, double-blind, multicentre, phase 3 trial (SYNERGY II) of patients with "wet" OAB symptoms (urinary frequency and urgency with incontinence) for ≥3 mo. The study was conducted from March 2014 to September 2016; with 1829 patients randomised. The full analysis set was comprised of 1794 patients.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary objective was safety, measured as treatment-emergent adverse events (TEAEs). Efficacy was measured as the change from baseline to the end of treatment in the mean number of incontinence episodes/24h and micturitions/24h.

RESULTS AND LIMITATIONS

The median age was 60 yr (range 19-86 yr) and 1434 patients (80%) were female. Overall, 856 patients (47%) experienced ≥1 TEAE. TEAE frequency was slightly higher in the combination group (596 patients, 49%; mirabegron 126 patients, 41%; solifenacin 134 patients, 44%). Serious TEAEs were reported by 67 patients (3.7%); one was considered possibly treatment-related (mirabegron group, atrial fibrillation). Dry mouth was the most common TEAE (combination 74 patients, 6.1%; solifenacin 18 patients, 5.9%; mirabegron 12 patients, 3.9%). Combination therapy was statistically superior to mirabegron and solifenacin for the number of incontinence episodes (vs mirabegron: adjusted mean difference [AMD] -0.5, 95% confidence interval [CI] -0.7 to -0.2, p<0.001; vs solifenacin: AMD -0.1, 95% CI -0.4 to 0.1, p=0.002) and micturitions (vs mirabegron: AMD -0.5, 95% CI -0.8 to -0.2, p<0.001; vs solifenacin: AMD -0.4, 95% CI -0.7 to -0.1, p=0.004).

CONCLUSIONS

Mirabegron and solifenacin combination treatment for OAB symptoms was well tolerated over 12 mo and led to efficacy improvements over each monotherapy. This innovative combination is a treatment option that could become widely used in the clinic.

PATIENT SUMMARY

This study looked at the safety and efficacy of a combination of solifenacin succinate 5mg plus mirabegron 50mg tablets over 12 mo in patients with the overactive bladder (OAB) symptoms of increased urination frequency, heightened urgency to urinate, and unintentional passing of urine. We compared this treatment with solifenacin succinate 5mg or mirabegron 50mg alone, and found that the combination treatment was well tolerated by patients and led to greater improvements in symptoms. This novel combination could be an improved treatment option in the clinical setting for patients with OAB. This study is registered at ClinicalTrials.gov as NCT02045862.

Pharmacokinetic Interactions Between Mirabegron and Metformin, Warfarin, Digoxin or Combined Oral Contraceptives

BACKGROUND AND OBJECTIVES

Mirabeg ron is a selective β3-adrenoceptor agonist approved for the treatment of overactive bladder (OAB). Four phase 1 studies were conducted in healthy subjects to evaluate the potential for pharmacokinetic interactions between mirabegron and metformin, warfarin, digoxin, or a combination oral contraceptive (COC).

METHODS

Thirty-two male subjects received metformin (500 mg twice daily) or mirabegron (160 mg once daily) alone, in combination or with placebo. Twenty-four male and female subjects received single doses of warfarin (25 mg) alone and in combination with mirabegron (100 mg once daily). Twenty-five male and female subjects were administered digoxin (0.25 mg) alone and in combination with mirabegron (100 mg once daily). Thirty female subjects received low-dose COC containing ethinylestradiol (EE)/levonorgestrel (LNG) (30/150 µg once daily) in combination with mirabegron (100 mg once daily) or placebo. Pharmacokinetic parameters were determined by non-compartmental methods. Absence of a Pharmacokinetic interaction was concluded if the 90 % confidence intervals (CI) of geometric least-squares means ratio of area under the curve (AUC) and maximum concentration (C _max) were contained within the standard 80-125 % no-effect boundaries. The effect of mirabegron on warfarin International Normalized Ratio (INR) was also assessed.

RESULTS

Mirabegron increased digoxin AUC and C_max by 27 and 29 %, respectively, indicating that mirabegron is a weak inhibitor of P-glycoprotein (P-gp) in vivo. Co-administration of mirabegron did not affect the pharmacokinetics of metformin, warfarin, EE and LNG, or warfarin INR, except for a slight extension of the 90 % CI for the C _max ratio for metformin (lower limit 79 %). Metformin decreased mirabegron AUC and C _max by 21 %. Most treatment-emergent adverse events were mild, and all resolved by study end.

CONCLUSIONS

No dose adjustment of either drug is required when mirabegron is administered concomitantly with metformin, warfarin or COC. Patients receiving mirabegron with digoxin may require additional monitoring of digoxin concentrations with dose adjustments where necessary, due to its narrow therapeutic index.

No. 353-Treatments for Overactive Bladder: Focus on Pharmacotherapy - An Addendum

OBJECTIVE

This technical update addendum reviews success rates and comparative evidence of the anticholinergic fesoterodine, as well as mechanism of action, safety profile, success rates, and comparative evidence of the β3 agonist mirabegron in the treatment of non-neurogenic overactive bladder syndrome (OAB). This adds to OAB pharmacotherapy recommendations initially published in 2012.

INTENDED USERS

Residents and other trainees, primary care practitioners, gynaecologists, urologists, urogynaecologists, and other health care providers who assess, counsel, and treat women with OAB.

TARGET POPULATION

Adult women with symptomatic OAB.

OPTIONS

This addition relates to fesoterodine, mirabegron, and anticholinergic-β3 agonist combination pharmacotherapy.

OUTCOMES

The outcomes of interest are clinical efficacy of fesoterodine compared with no treatment or other OAB therapies; mechanism of action and safety profile of mirabegron, clinical efficacy of mirabegron compared to no treatment or other OAB therapies; clinical efficacy of anticholinergic-β3 agonist combination pharmacotherapy for OAB.

EVIDENCE

PubMed, Medline, and the Cochrane Database were searched using the key words "fesoterodine" and "mirabegron." Results were restricted to English or French and human clinical and pharmacological research. Animal research and clinical studies including only male participants were excluded. Articles were included until the end of December 2016. Grey literature was not searched. Clinical practice guidelines, guidelines of specialty societies, and systematic reviews were included. RCTs and observational studies were included when evidence for the outcome of interest or in the target population was not available from systematic reviews. New studies not yet included in systematic reviews were also included. References of included articles were also searched to ensure comprehensive inclusion of relevant literature.

VALUES

The content and recommendations were drafted and agreed upon by the principal author, as well as members of the Urogynaecology Committee. The Board of the SOGC approved the final draft for publication. The quality of evidence was rated using the criteria described in the Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology framework. The Summary of Findings is available upon request.

BENEFITS, HARMS, AND/OR COSTS

It is expected that this technical update will benefit patients with OAB by providing physicians and other interested health care providers with additional options for and knowledge of safe and effective OAB pharmacotherapy. The benefits clearly outweigh the potential harms or costs of implementation of this technical update, although there are no direct harms or costs identified. UPDATES: "Evidence will be reviewed 5 years after publication to decide whether all or part of the document should be updated. However, if important new evidence is published prior to the 5-year cycle, the review process may be accelerated for a more rapid update of some recommendations."

SPONSORS

Not applicable.

RECOMMENDATIONS

Dual Therapy for Refractory Overactive Bladder in Children: A Prospective Open-Label Study

PURPOSE

Mirabegron (β3 adrenoreceptor agonist) is a new molecule with a mechanism of action distinct from antimuscarinics. Combination therapy with solifenacin was recently studied in an adult population. We evaluated the efficacy and safety of mirabegron as add-on therapy to treat urinary incontinence in children with idiopathic overactive bladder refractory/intolerant to antimuscarinics.

MATERIALS AND METHODS

A prospective off-label study using add-on regimens of mirabegron was conducted in pediatric patients presenting with no symptom improvement while undergoing intensive behavioral and medical therapies and/or significant side effects while undergoing antimuscarinic dose escalation. Our primary outcome was better reported efficacy than with the use of prior antimuscarinic monotherapy. Secondary end points were tolerability, safety and satisfaction. Efficacy and tolerability were assessed based on voiding diaries, post-void residuals, urine cultures, electrocardiograms and vital signs. Families were questioned regarding continence, side effects and compliance. Wilcoxon signed-rank test was used for statistical analysis.

RESULTS

A total of 35 patients were recruited at a median age of 10.3 years and were administered add-on mirabegron for a median of 16.4 months. Median bladder capacity improved from 50% to 74% expected bladder capacity (p <0.001). Continence improved in all patients, with 12 being completely dry. Post-void residual was increased in 2 patients and 1 urinary tract infection was reported. Seven patients reported mild or moderate side effects, with 2 withdrawals because of side effects (1 patient) and post-void residual (1).

CONCLUSIONS

Add-on mirabegron appears to be a safe alternative for children with refractory overactive bladder. Dual therapy is well tolerated and adjusted dose regimen appears safe in this first pediatric study.

Safety and efficacy of mirabegron as 'add-on' therapy in patients with overactive bladder treated with solifenacin: a post-marketing, open-label study in Japan (MILAI study)

OBJECTIVE

To examine the safety and efficacy of mirabegron as 'add-on' therapy to solifenacin in patients with overactive bladder (OAB).

PATIENTS AND METHODS

This multicentre, open-label, phase IV study enrolled patients aged ≥20 years with OAB, as determined by an OAB symptom score (OABSS) total of ≥3 points and an OABSS Question 3 score of ≥2 points, who were being treated with solifenacin at a stable dose of 2.5 or 5 mg once daily for at least 4 weeks. Study duration was 18 weeks, comprising a 2-week screening period and a 16-week treatment period. Patients meeting eligibility criteria continued to receive solifenacin (2.5 or 5 mg once daily) and additional mirabegron (25 mg once daily) for 16 weeks. After 8 weeks of treatment, the mirabegron dose could be increased to 50 mg if the patient's symptom improvement was not sufficient, if he/she was agreeable to the dose increase, and the investigator judged that there were no safety concerns. Safety assessments included adverse events (AEs), laboratory tests, vital signs, 12-lead electrocardiogram, QT corrected for heart rate using Fridericia's correction (QTcF) interval and post-void residual (PVR) volume. Efficacy endpoints were changes from baseline in OABSS total score, OAB questionnaire short form (OAB-q SF) score (symptom bother and total health-related quality of life [HRQL] score), mean number of micturitions/24 h, mean number of urgency episodes/24 h, mean number of urinary incontinence (UI) episodes/24 h, mean number of urgency UI episodes/24 h, mean volume voided/micturition, and mean number of nocturia episodes/night. Patients were instructed to complete the OABSS sheets at weeks -2, 0, 8 and 16 (or at discontinuation), OAB-q SF sheets at weeks 0, 8 and 16 (or at discontinuation) and patient voiding diaries at weeks 0, 4, 8, 12 and 16 (or at discontinuation).

RESULTS

Overall incidence of drug-related treatment-emergent AEs (TEAEs) was 23.3%. Almost all TEAEs were mild or moderate. The most common TEAE was constipation, with similar incidence in the groups receiving a dose increase to that observed in the groups maintained on the original dose. Changes in PVR volume, QTcF interval, pulse rate and blood pressure were not considered to be clinically significant and there were no reports of urinary retention. Significant improvement was seen for changes in efficacy endpoints from baseline to end of treatment (EOT) in all groups (patients receiving solifenacin 2.5 or 5 mg + mirabegron 25 or 50 mg).

CONCLUSIONS

Add-on therapy with mirabegron 25 mg once daily for 16 weeks, with an optional dose increase to 50 mg at week 8, was well tolerated in patients with OAB treated with solifenacin 2.5 mg or 5 mg once daily. There were significant improvements from baseline to EOT in OAB symptoms with combination therapy with mirabegron and solifenacin. Add-on therapy with mirabegron and an antimuscarinic agent, such as solifenacin, may provide an attractive therapeutic option.

Combination treatment with mirabegron and solifenacin in patients with overactive bladder: efficacy and safety results from a randomised, double-blind, dose-ranging, phase 2 study (Symphony)

BACKGROUND

Combining the β3-adrenoceptor agonist mirabegron and the antimuscarinic (AM) agent solifenacin may improve efficacy in the treatment of overactive bladder (OAB) while reducing the AM side effects.

OBJECTIVE

The primary objective was to evaluate the efficacy of combinations of solifenacin/mirabegron compared with solifenacin 5mg monotherapy. The secondary objective was to explore the dose-response relationship and the safety/tolerability compared with placebo and monotherapy.

DESIGN, SETTING, AND PARTICIPANTS

A phase 2, factorial design, randomised, double-blind, parallel-group, placebo- and monotherapy-controlled trial, conducted at 141 sites in 20 European countries. Male and female patients were aged ≥18 yr with symptoms of OAB for ≥3 mo.

INTERVENTION

A total of 1306 patients (66.4% female) were randomised to 12 wk of treatment in 1 of 12 groups: 6 combination groups (solifenacin 2.5, 5, or 10 mg plus mirabegron 25 or 50 mg), 5 monotherapy groups (solifenacin 2.5, 5, or 10 mg, or mirabegron 25 or 50 mg), or placebo.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Change from baseline to end of treatment in mean volume voided per micturition (MVV) (primary end point) and mean numbers of micturitions per 24 h, incontinence episodes per 24 h, and urgency episodes per 24 h were analysed using an analysis of covariance model. Safety assessments included treatment-emergent adverse events (TEAEs), blood pressure, pulse rate, postvoid residual (PVR) volume, and laboratory and electrocardiography (ECG) parameters.

RESULTS AND LIMITATIONS

Compared with solifenacin 5 mg monotherapy, all combinations with solifenacin 5 or 10 mg significantly improved MVV, with adjusted differences ranging from 18.0 ml (95% confidence interval [CI], 5.4-30.0) to 26.3 ml (95% CI, 12.0-41.0). Three combination groups significantly reduced micturition frequency compared with solifenacin 5 mg, ranging from -0.80 (95% CI, -1.39 to -0.22) to -0.98 (95% CI, -1.68 to -0.27). Five of six combinations significantly reduced urgency episodes compared with solifenacin 5 mg, ranging from -0.98 (95% CI, -1.78, to -0.18) to -1.37 (95% CI, -2.03 to -0.70). No dose-related trends in TEAEs, blood pressure, pulse rate, PVR volume, or laboratory or ECG parameters were observed between combination and monotherapy groups, although the incidence of constipation was slightly increased with combination therapy.

CONCLUSIONS

Combination therapy with solifenacin/mirabegron significantly improved MVV, micturition frequency, and urgency compared with solifenacin 5 mg monotherapy. All combinations were well tolerated, with no important additional safety findings compared with monotherapy or placebo.

PATIENT SUMMARY

To improve treatment of overactive bladder (OAB), mirabegron/solifenacin in combination was compared with each drug alone and placebo. Combination therapy improved OAB symptoms and had similar safety and acceptability.

TRIAL REGISTRATION

Clinical trials.gov: NCT01340027.

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

AIMS

Mirabegron, the first β3 -adrenoceptor agonist to enter clinical practice, has a different mechanism of action from antimuscarinic agents. This review presents data on the efficacy, safety, and tolerability of mirabegron in studies conducted to date.

METHODS

All clinical data on mirabegron that are currently in the public domain are included, including some in-press manuscripts.

RESULTS

In Phase III clinical trials in patients with overactive bladder (OAB), mirabegron at daily doses of 25, 50, and 100 mg demonstrated significant efficacy in treating the symptoms of OAB, including micturition frequency, urgency incontinence, and urgency. Significant improvements in micturition frequency, urgency incontinence, and mean volume voided/micturition were seen as early as the first assessment (week 4) for mirabegron 50 and 100 mg, and were maintained throughout treatment. Responder analyses showed a significant improvement with mirabegron 50 and 100 mg in terms of dry rates, ≥50% reduction in mean number of incontinence episodes/24 hr, and the proportion of patients with ≤8 micturitions/24 hr at final visit. The benefit of mirabegron 50 and 100 mg was also evident in patients ≥65 years of age, and in both treatment-naïve patients and those who previously discontinued antimuscarinic therapy. These data therefore demonstrate a clinically meaningful benefit with mirabegron in the objective endpoints of OAB. Assessment of measures of health-related quality of life and treatment satisfaction showed that patients perceived treatment with mirabegron as meaningful. In OAB clinical trials of up to 12 months mirabegron appeared to be well tolerated. The most common adverse events (AEs) observed with mirabegron in clinical trials of up to 12 months were hypertension, nasopharyngitis, and urinary tract infection. The incidence of dry mouth was similar to placebo, and was between three and fivefold less than for tolterodine extended release 4 mg. Since dry mouth is the most bothersome AE associated with antimuscarinic drugs and often a reason for treatment discontinuation, mirabegron may be a valuable treatment option for these patients.

CONCLUSIONS

In Phase III clinical trials, mirabegron at daily doses of 25, 50, and 100 mg demonstrated significant efficacy in treating symptoms of OAB and, at doses of 50 and 100 mg, demonstrated significant improvements versus placebo on key secondary endpoints, as early as the first assessment (week 4), and these were maintained throughout treatment. In OAB clinical trials of up to 12 months, mirabegron appeared to be well tolerated.