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

Results of a study examining the use of onabotulinumtoxinA in pediatric patients with overactive bladder

BACKGROUND

There is a lack of approved treatments for pediatric patients with overactive bladder (OAB) with inadequate response to anticholinergic therapy. OnabotulinumtoxinA 100U is approved to treat OAB in adults based on data from randomized, pivotal trials.

OBJECTIVE

To investigate the efficacy and safety of onabotulinumtoxinA treatment of OAB in children aged 12-17 years who were not adequately managed with anticholinergics.

STUDY DESIGN

In this multinational, multicenter, randomized, double-blind, parallel-group, multiple-dose study (NCT02097121), pediatric patients with OAB were randomized 1:1:1 to receive onabotulinumtoxinA 25U, 50U, or 100U (≤6 U/kg). Patients could request retreatment starting at week 12. The primary endpoint was change from baseline to week 12 after treatment 1 in daily frequency of daytime urinary incontinence (UI) episodes. Safety assessments evaluated treatment-emergent adverse events (TEAEs).

RESULTS

Of 68 screened patients, 55 received ≥1 treatment. Mean age was 14 years; 85.5% of patients were female. At week 12 after treatment 1, least squares mean change from baseline in daily frequency of daytime UI episodes showed a numerically greater reduction in the 100U arm (-2.4) versus the 25U arm (-1.4; P = 0.38), with a significant within-group change from baseline in the 100U arm (P = 0.0027). Achievement of treatment response was significantly greater with onabotulinumtoxinA 100U vs 25U (Figure). Median time to request retreatment was ≥16 weeks in all groups. The most frequently reported TEAEs were nasopharyngitis (10.9%) and urinary tract infection (UTI; 10.9%). Urinary retention was observed in 1 patient during treatment cycle 2; there were no serious TEAEs of UTI or urinary retention. Throughout 2 additional treatment cycles continued efficacy for the 100U dose arm was observed along with a consistent safety profile.

DISCUSSION

Change in daily frequency of UI episodes at week 12 in treatment cycle 1 was not significantly different between arms. However, ≥50% response rate was significantly higher with onabotulinumtoxinA 100U versus 25U. Enrollment challenges that lowered the sample size could have reduced statistical power. Also, the lack of a placebo arm and the observed benefit with the 25U comparator limited interpretation.

CONCLUSIONS

OnabotulinumtoxinA injections were well tolerated in children with OAB at all doses studied. Although the primary endpoint was not met, the significantly greater treatment response rate observed with onabotulinumtoxinA 100U versus 25U suggests additional benefit of the higher dose, without additional safety concerns.

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.

Vibegron shows high efficacy in pediatric patients with refractory daytime urinary incontinence

PURPOSE

Sparse published reports exist nowadays on vibegron and pediatric overactive bladder, so its usefulness of this agent remains unclear. The purpose of this study was to clarify the effectiveness of vibegron for pediatric cases of daytime urinary incontinence (DUI), including refractory cases.

METHODS

Participants comprised 57 patients treated with vibegron for DUI from March 2019 to April 2022. To investigate treatment outcomes and risk factors for pediatric patients with refractory DUI, the following factors were evaluated: age at initiatial administration; frequency of DUI; duration of vibegron treatment; presence of neurodevelopmental disorders (NDDs); presence of constipation; and anticholinergic medications before and after initiation of treatment.

RESULTS

Patients included 38 boys and 19 girls with a median age at initial administration of 111 months (range: 64-202 months) and a median administration term of 6 months (range: 1-33 months). With treatment for 6 months, the response rate (complete response + partial response) was 68.3%. A total of 24 cases with NDD showed a 72.0% response rate at 6 months. As for the relationship between anticholinergic agents and vibegron, 15 cases were treated with vibegron as the first choice without anticholinergics (First-choice cases), and 33 cases were treated with vibegron alone after switching from anticholinergics (Switch cases). Vibegron was used in combination with anticholinergic agents in 9 cases (Add-on cases). Response rates at 6 months were 85.0% in First-choice cases, 66.3% in Switch cases, and 40.7% in Add-on cases. Univariate analyses failed to identify any significant risk factors for refractory cases.

CONCLUSIONS

Vibegron was effective in pediatric cases of DUI, with efficacy demonstrated within a short time in many cases. Vibegron is expected to play a significant role in the treatment of DUI in pediatric cases.