Preliminary results of a dose-finding study for botulinum toxin-A in patients with idiopathic overactive bladder: 100 versus 150 units.

AIMS: To evaluate the clinical outcomes of two different doses of BTX-A in patients with I-OAB.

METHODS: This investigator initiated, randomized trial was designed to evaluate clinical differences in outcomes for 100 versus 150 U BTX-A in patients with I-OAB. Patients with OAB-Wet and OAB-Dry were randomized to receive 100 or 150 U BTX-A intra-detrusor injection. For patients with OAB-Wet, the primary outcome of interest was change in daily UUI episodes, and for those with OAB-Dry the primary outcome measure was change in number of daily voids as determined by 3-VD. Statistical comparisons were made both pre- and post-injection and also between different treatment groups to assess the superiority of one dose versus the other.

RESULTS: Forty-four patients enrolled in the study; 10 OAB-Dry and 12 OAB-Wet patients received 100 U and another 10 OAB-Dry and 12 OAB-Wet patients received 150 U. No significant differences in outcome measure were noted between those receiving 100 versus 150 U. Patients with OAB-Wet tended to be completely dry more frequently if they received the 150 U dose, but this was not statistically significant. No differences in urodynamics outcomes were noted between the groups. QOL was significantly improved in both groups with no difference between the different doses.

CONCLUSIONS: In patients with I-OAB, preliminary results indicate that 100 U BTX-A and 150 U BTX-A are equivalent in terms of symptom reduction and QOL improvement.