Long-term efficacy of Mirabegron-anticholinergic combination in paediatric neurogenic bladder

The Mirabegron-anticholinergic (MAC) combination has proven effective as a step-up strategy in managing paediatric neurogenic bladder following anticholinergic medication and botulinum toxin (BTX) therapy. This study assesses the long-term efficacy of MAC in children with neurogenic bladder.

A retrospective chart review was conducted from 2015 to 2023, including consecutive paediatric patients receiving Mirabegron (25/50 mg) with an anticholinergic agent (solifenacin 16, tolterodine 7, oxybutynin 7, trospium 1). MAC was started where previous therapy had failed to control bladder pressures. The study cohort had a minimum of 2 years of videourodynamics (VUD) follow-up (2-7 years) and 3.5 years of symptomatic follow-up (2-7 years). All patients used CIC. Efficacy was determined from VUD data, symptom reports, and adverse events (AEs) with upper tract status. Statistical analysis used median values, Friedman's two-way analysis of variance by ranks and Chi-squared testing (p < 0.05).

The analysis included 31 children (median age at start: 8 years, range: 4-15 years; 12 females) with neurogenic bladder due to myelomeningocele (17), closed spinal dysraphism (11), or spinal cord injury/tumour (3). A minimum of 8 weeks post-MAC therapy, significant improvements were observed in VUD parameters of: bladder capacity, compliance, and maximum detrusor pressure. These improvements were sustained at final VUD follow-up (median 33 months) in 21 patients (Summary Table). However, 9 patients who showed initial VUD improvement at median 5 months lost the effect by median 27 months, with 4 non-adherent patients and 5 with lower initial bladder compliance. Initial symptom improvement occurred in 25 patients, sustained for a median of 43 months (range: 23-85) in 19 patients. Adverse events were minimal (constipation, fatigue, and UTI reported in one patient each). No significant changes in blood pressure or upper tract status were observed.

MAC combination effectively manages paediatric neurogenic bladder resistant to AC and BTX therapy. The VUD benefits (present in 77.8 %) and symptom benefits (present in 61 %) are maintained and ongoing for a significant period (median 33 and 43 months respectively) when commenced before significant loss of compliance. MAC presents a promising long-term treatment option for the paediatric neurogenic bladder.