BACKGROUND: Onabotulinumtoxin A (OnaBoNT/A, Botox®) is effective in the treatment of neurogenic detrusor overactivity, however this therapy can fail. In a prospective study, we analyzed patient serum for BoNT/A antibodies (BoNT/A-AB) as a possible cause of therapy failure. METHODS: 17 patients (average age 14.5 years) who had neurogenic detrusor overactivity were admitted for repeated OnaBoNT/A injection into the detrusor muscle. We analyzed their serum for BoNT/A-AB. The clinical findings were correlated with the incidence of BoNT/A-AB. RESULTS: Positive BoNT/A-AB were clearly or marginally determined in 6 patients. Therapy had failed in all 6. In 4 of the 6, therapy might have failed because of a low-compliance bladder (3 patients) or tethered-cord syndrome (1), but BoNT/A-AB were found as the only possible cause in 2 patients. Thus, the incidence of BoNT/A-AB in the 17 patients was 35%, and the antibodies were clinically significant in 12%. All patients with BoNT/A-AB had a history of recurrent urinary tract infections. CONCLUSIONS: Patients who show a failure of therapy after OnaBoNT/A injections for which no other causes can be determined should have their serum checked for BoNT/A-AB. Recurrent urinary tract infection might be a predisposing factor for BoNT/A-AB.
BACKGROUND: Onabotulinumtoxin A (OnaBoNT/A, Botox®) is effective in the treatment of neurogenic detrusor overactivity, however this therapy can fail. In a prospective study, we analyzed patient serum for BoNT/A antibodies (BoNT/A-AB) as a possible cause of therapy failure. METHODS: 17 patients (average age 14.5 years) who had neurogenic detrusor overactivity were admitted for repeated OnaBoNT/A injection into the detrusor muscle. We analyzed their serum for BoNT/A-AB. The clinical findings were correlated with the incidence of BoNT/A-AB. RESULTS: Positive BoNT/A-AB were clearly or marginally determined in 6 patients. Therapy had failed in all 6. In 4 of the 6, therapy might have failed because of a low-compliance bladder (3 patients) or tethered-cord syndrome (1), but BoNT/A-AB were found as the only possible cause in 2 patients. Thus, the incidence of BoNT/A-AB in the 17 patients was 35%, and the antibodies were clinically significant in 12%. All patients with BoNT/A-AB had a history of recurrent urinary tract infections. CONCLUSIONS:Patients who show a failure of therapy after OnaBoNT/A injections for which no other causes can be determined should have their serum checked for BoNT/A-AB. Recurrent urinary tract infection might be a predisposing factor for BoNT/A-AB.