Introduction

To assess the outcomes of switching to a different brand of botulinum toxin A (BTA), from Onabotulinum toxin A (OTA) (Botox) to abobotulinum toxin A (ATA) (Dysport) in case of failure of intradetrusor injections (IDI) of OTA in the treatment of neurogenic detrusor overactivity (NDO).

Methods

The charts of all patients who underwent a switch to IDI of ATA after failure of an IDI of OTA at six departments of neurourology were retrospectively reviewed. The main outcomes of interest were the bladder diary data and four urodynamic parameters: maximum cystometric capacity (MCC), maximum detrusor pressure (PDET max) and volume at first uninhibited detrusor contraction (UDC). Data were compared before and after treatment with OTA and ATA, using Stuart, Wilcoxon and paired-t tests for paired samples and univariate logistic regression was performed to seek for predictors of switch success.

Results

Out of 57 patients included, 38.6% were primary non-responders to Botox, and in secondary non-responder a median number of 5 OTA IDI were performed before failure (range 1-17). Persistent urinary incontinence was observed in 84.2% patients, and 75.4% had persistent detrusor overactivity. Six weeks after the first injection of Dysport, no adverse events were reported. A significant decrease in number of urinary incontinence episodes per day was observed in 52.63% of patients (p <0.001) and all patients experienced a reduction in PDET Max (-8.1 cmH20 on average; p=0.003). MCC significantly increased by a mean of 41.2 ml (p=0.02). The proportion of patients with no UDC increased significantly at after ATA injections (from 15.79% to 43.9%; p=0.0002). Hence, 32 patients draw clinical and/or urodynamic benefits from the botulinum toxin switch from OTA to ATA (56.14%). After a median follow up of 21 months, 87% of responders to BTA switch were still treated successfully with BTA. In univariate analysis, three variables were associated with BTA switch success: low MCC before first ATA IDI (OR=20.4;p=0.01) and dose of ATA (OR= 10.9; p=0.048) were predictive of increased success rates; poor compliance was predictive of lower success rate (OR=0.2; p=0.04).

Conclusions

Most patients refractory to OTA (Botox) (56.14%) draw benefits from the switch to ATA (Dysport). Low MCC and dose of ATA were predictive of success of BTA switch while poor compliance was predictive of failure.

Funding

none