How long does the effect of botulinum toxin in neurogenic patients last? An analysis of the subset of “good responders”

Background The aim of this study was to assess long‐term efficacity of botulinum neurotoxin A (BoNT‐A) in the treatment of neurogenic detrusor overactivity (NDO). Materials and Methods This was a retrospective monocentric study in a reference center. We included patients who received intradetrusor BoNT‐A for NDO between 2001 and 2015. The focus of our analysis was on patients defined as “good responders” (≥ 5 injections of intradetrusor BoNT‐A over a period of ≥5 years). The primary endpoint was the evaluation of long‐term efficacity of BoNT‐A. Recurrent NDO was monitored by the use of cystomanometry before the first injection and 1 month after each injection. The secondary objective was to assess the influence of NDO's etiology, age, and sex on the long‐term efficacity of the treatment. Results A total of 107 patients were included (60.7% with spinal cord injury [SCI] and 36.4% with multiple sclerosis [MS]). The mean follow‐up period was 83.7 months (66; 120). The mean number of injections was of 8.9 (5; 21). A total of 67.3% (n = 72) of patients were still controlled by treatment at the end of their follow‐up period. Therapeutic failure occurred in 30 patients (26.1%) with a cessation of BoNT‐A treatment at 76 months on average (median: 82.5 months). There was no significant impact of age ( P = .42), sex ( P = .35), or NDO's etiology (MS vs SCI; P = .54) on long‐term efficacy of BoNT‐A treatment. Conclusion The results of our study indicate that the application of BoNT‐A seems to be an effective and durable treatment in a large number of neurogenic patients after more than 10 years of follow‐up. However, botulinum toxin tolerance occurred in approximately 25% of patients.