Urodynamic evaluation of the efficacy of vibegron, a new β3-adrenergic receptor agonist, on lower urinary tract function in children and adolescents with overactive bladder

INTRODUCTION

Idiopathic overactive bladder (OAB) is defined as an urgency symptom with or without urge incontinence, which is not due to known neurological abnormalities. Since children present with variable symptoms, pediatric nonneurogenic idiopathic OAB is a condition that is difficult to diagnose and treat. Although there are few reports on bladder function in pediatric patients compared to adult patients, it can be useful for diagnosis. Antimuscarinic therapy is the pharmacological mainstay of OAB management. However, antimuscarinic use is limited by side effects and Insufficient effects. Vibegron, a new drug with a different mechanism of action (β3-adrenoreceptor agonist), was recently introduced for treating OAB in adults but has not been studied in the pediatric population.

OBJECTIVE

This study aimed to determine the efficacy and tolerability of vibegron in children and adolescents with idiopathic OAB.

STUDY DESIGN

We conducted a retrospective study enrolling pediatric patients with OAB whose symptoms did not improve with behavioral therapy or pharmaceutical therapy. Efficacy and tolerability were assessed via a question, and patients underwent video-urodynamic testing before and during treatment with once-daily 50 mg vibegron. Statistical differences were evaluated using Wilcoxon matched-pairs signed-rank tests.

RESULTS

Out of the 17 patients that were recruited, full study with two urodynamic studies were confirmed by 11 patients. OAB symptoms improved in 14 (82.4%) patients, and 3 patients discontinued treatment because of ineffectiveness. No patients discontinued treatment because of intolerance to vibegron. The median (IQR) first desire to void (133 [82-185]-161 [123-227] mL), bladder capacity (158 [136-238]-204 [150-257] mL), and bladder compliance (18.1 [9.1-76.7]-34.0 [30.0-82.3] mL/cm H₂O) improved significantly post treatment compared to before treatment. Detrusor overactivity disappeared in one of the eight patients with this condition. The parameters of voiding function did not change significantly after the administration of vibegron.

DISCUSSION

Treatment with vibegron significantly improved clinical and urodynamic parameters of pediatric OAB with no adverse effects. Little information is available regarding the feasibility of switching drugs when patients discontinue prior pharmacological therapy because of insufficient efficacy or poor tolerability in children. Vibegron may be a promising OAB treatment option with a better balance of efficacy and tolerability.

CONCLUSIONS

Vibegron is an alternative agent for pediatric patients with idiopathic OAB for improving both subjective symptoms and lower urinary tract function. Future prospective randomized studies with larger sample sizes must be conducted to validate the results of the present study.

Prospective Pilot Study of Mirabegron in Pediatric Patients with Overactive Bladder

BACKGROUND

Antimuscarinics are the pharmacologic mainstay of overactive bladder (OAB) management, but side effects limit their use. Mirabegron, a new molecule with a distinct mechanism of action (β3-adrenoreceptor agonist), was recently approved as monotherapy for idiopathic OAB in adults but has not been studied in the pediatric population.

OBJECTIVE

To evaluate the efficacy and safety of mirabegron to treat urinary incontinence in children with idiopathic OAB who were refractory to and/or intolerant of antimuscarinics.

DESIGN, SETTING, AND PARTICIPANTS

A prospective off-label study using mirabegron was conducted. Pediatric patients without symptom improvement under behavioral and medical therapies and/or with significant side effects with at least two different antimuscarinic agents were recruited.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Our primary outcome was better reported efficacy than with the use of prior anticholinergic medication. Secondary end points were tolerability, safety, and satisfaction. Efficacy and tolerability were assessed with voiding diaries, postvoid residuals, urine cultures, electrocardiogram, and vital signs. Families were questioned for continence, side effects, compliance, and Patient Perception of Bladder Condition (PPBC) questionnaire. The Wilcoxon rank sum test and Wilcoxon signed rank test were used for statistical analysis.

RESULTS AND LIMITATIONS

A total of 58 patients were recruited at a median age of 10.1 yr and were on mirabegron for a median of 11.5 mo. Median bladder capacity improved from 150ml to 200ml (p<0.001). Continence improved in 52 of 58, with 13 being completely dry. Median PPBC improved from 4.0 to 2.0 (p<0.001). Eight patients reported mild or moderate side effects. Absence of a placebo group is a limitation of the study.

CONCLUSIONS

Mirabegron, a novel first-in-class therapy, appeared as a safe and effective alternative for children with idiopathic OAB refractory to antimuscarinics.

PATIENT SUMMARY

We evaluated the efficacy and safety of mirabegron to treat incontinence in pediatric patients. Continence, median voided volumes, and quality of life were improved after the introduction of mirabegron, and few side effects were reported.