Mirabegron as part of combination therapy for treatment refractory neurogenic bladder in pediatric patients with spina bifida

Introduction

Medical therapy for patients with neurogenic bladder secondary to spina bifida is a key element in their management. Mirabegron has been shown to improve abnormal bladder wall dynamics in the neurogenic bladder (NGB) population, but there is limited information on its efficacy as additive therapy in the treatment of refractory NGB in pediatric literature.

Objective

This study assessed the utility of mirabegron as combination therapy in pediatric patients with spina bifida who have insufficient improvement of bladder dynamics on antimuscarinic monotherapy. We hypothesized that using mirabegron in combination with antimuscarinic therapy would lead to improved bladder dynamics on repeat urodynamic studies.

Study design

This was a retrospective review of pediatric patients treated at 2 centers were included if there were high-risk urodynamic findings and/or persistent incontinence on a single antimuscarinic agent. Pre and post dual therapy initiation urodynamic assessment was performed.

Results

We included 103 patients at a median age of 10.7 years on a median of 166 days of treatment. Dual therapy lowered detrusor opening pressures and end filling pressures, in addition to improving detrusor overactivity in 32 % of patients, even in the patients with the highest risk bladders (Figure).

Discussion

Limitations of the study include the retrospective design, the subjectivity of the treating physician in initiating Mirabegron, and the variability in urodynamic assessment. Our findings are consistent with the benefits of dual therapy in adult patients, extending this treatment option to the pediatric population.

Conclusion

The addition of mirabegron resulted in improvement in storage pressures and subjective incontinence in pediatric spina bifida patients not adequately managed with a single antimuscarinic agent.