Different number of intravesical onabotulinumtoxinA injections for patients with refractory detrusor overactivity do not affect treatment outcome: A prospective randomized comparative study.

[AIMS] To examine the therapeutic effects and safety of different numbers of intravesical onabotulinumtoxinA (BoNT-A) injection for patients with detrusor overactivity (DO) refractory to antimuscarinics.

[METHODS] Patients with DO, at least one daily episode of urgency or urgency incontinence refractory to previous antimuscarinics were randomly assigned to receive 10, 20, or 40 intravesical BoNT-A injections 100 U in 10 mL in the bladder body. Treatment results were assessed with global response assessment GRA, OAB symptom score OAB-SS, urgency severity scale USS, patient perception of bladder condition PPBC, voiding diary, and urodynamic parameters. The primary endpoint was the comparison of the rates of successful treatment, which was defined as GRA ≥ 1 after treatment, between the groups. The secondary endpoints were the comparisons of the changes in the voiding diary, urodynamic parameters, individual AEs between the groups.

[RESULTS] Sixty-seven patients were randomized into three groups. Patients with GRA ≥ 1 at 1, 3, and 6 months after treatment were comparable between the groups. The average OAB-SS and USS and PPBC scores decreased whereas the average postvoid residual urine volume increased in all three groups. Changes in urodynamic and voiding diary parameters were also comparable between the groups. There were no significant differences in the rates of AEs and urinary tract infection after treatment.

[CONCLUSIONS] Different numbers of intravesical BoNT-A injections produced similar therapeutic and adverse effects. We therefore believe that 1 ml BoNT-A injections (10 U) at 10 sites are adequate to achieve an optimal therapeutic effect in OAB patients. Neurourol. Urodynam. 35:717-723, 2016. © 2015 Wiley Periodicals, Inc.