OBJECTIVES: Botulinum toxin A (BTX-A) injection into the detrusor muscle has changed therapy options for patients with overactive bladder (OAB). However, in some patients, therapy fails or the effects of BTX-A decrease. The aim of this prospective study was to evaluate the incidence of BTX-A antibodies (BTX-A Abs) after injection of BTX-A and its clinical relevance. METHODS: 31 patients (27 women, 4 men) were treated with BTX-A for OAB between January 2009 and August 2010. Eleven patients were treated once, 16 patients were treated twice and 4 patients were treated three times. Blood was collected before and 3 months after the BTX-A injection and BTX-A Abs were determined. RESULTS: In 5 patients (16%) BTX-A Abs were detectable after the BTX-A injection. The BTX-A Ab titer was clearly positive in 1 patient (3.2%). This patient showed complete failure of BTX-A therapy. In 4 patients (13%) BTX-A Abs were slightly positive after the first BTX-A injection. The second BTX-A injection showed no positive effects in only 1 patient with borderline BTX-A Ab titers; the second BTX-A injection was successful in 2 patients. CONCLUSIONS: The incidence of BTX-A Abs should be verified in nonresponders. More data are necessary to check the clinical relevance and risk of BTX-A Ab formation, especially in long-term follow-up, to optimize patient selection for this minimally invasive treatment option in OAB.
OBJECTIVES: Botulinum toxin A (BTX-A) injection into the detrusor muscle has changed therapy options for patients with overactive bladder (OAB). However, in some patients, therapy fails or the effects of BTX-A decrease. The aim of this prospective study was to evaluate the incidence of BTX-A antibodies (BTX-A Abs) after injection of BTX-A and its clinical relevance. METHODS: 31 patients (27 women, 4 men) were treated with BTX-A for OAB between January 2009 and August 2010. Eleven patients were treated once, 16 patients were treated twice and 4 patients were treated three times. Blood was collected before and 3 months after the BTX-A injection and BTX-A Abs were determined. RESULTS: In 5 patients (16%) BTX-A Abs were detectable after the BTX-A injection. The BTX-A Ab titer was clearly positive in 1 patient (3.2%). This patient showed complete failure of BTX-A therapy. In 4 patients (13%) BTX-A Abs were slightly positive after the first BTX-A injection. The second BTX-A injection showed no positive effects in only 1 patient with borderline BTX-A Ab titers; the second BTX-A injection was successful in 2 patients. CONCLUSIONS: The incidence of BTX-A Abs should be verified in nonresponders. More data are necessary to check the clinical relevance and risk of BTX-A Ab formation, especially in long-term follow-up, to optimize patient selection for this minimally invasive treatment option in OAB.