Refractory idiopathic Overactive Bladder (iOAB) can be defined based on lack of adherence to first- and second- line treatments regardless of the underlying cause. Anticholinergics drugs are the first- line of pharmacotherapy therapy for OAB but complications related to autonomic nervous system make it as an unpleasant strategy, which the most patients would prefer to quit it. Patients with refractory iOAB can be treated with Onabotulinumtoxin A (Onabot/A) intradetrusor injections, with positive results in the short- term follow- up. In this study, we evaluated the long- term effectiveness, safety and treatment’s satisfaction of Onabot/A intradetrusor repeat injections in a group of patients with refractory iOAB. Persistence rate to treatment in along term follow up was also evaluated.

From January 2000 to October 2018, 139 refractory wet- iOAB patients who previously cycled different anticholinergics (i.e.: tolterodine, propiverine, solifenacine) were treated with Onabot/A intradetrusor injections. Daily frequency of urinary incontinence (UI) episodes, recorded with the 3- day voiding diary and satisfaction to treatment, scored by the Visual Analogue Scale (VAS), both obtained at the last evaluation before the neurotoxin treatment, were evaluated. All patients received Onabot/A (100 U) repeat intradetrusor injections under cystoscopic guidance in an outpatient basis. Onabot/A treatment was repeated when urinary symptoms worsened. Any eventual side effect was also recorded.
Kruskal Wallis test with Dwass-Steel-Chritchlow-Fligner post-hoc test has been used to make comparisons on daily UI episodes and VAS scores frequencies among different Onabot/A treatments’ groups.

Fifty- one patients received 1 to 4 repeat injections, 45 patients 5 to 9 and 24 patients ≥10 repeat injections. Median/IQR of UI episodes/day and of VAS score were similar among the 3 different groups at baseline. After treatment, median/IQR of daily UI episodes was higher in patients who received 1-4 repeat injections as compared to patients treated with ≥10 repeat injections (p=0.0122). Median/IQR VAS scores was higher in patients who received 1-4 repeat injections as compared to patients treated with 5-9 and ≥10 repeat injections (p=0.0002 and p=0.0024, respectively, table). 19 of these patients dropped out due to: lack of efficacy (8 pts), request of a permanent solution (neuromodulation, 4 pts), pregnancies (2 pts), need for surgery (3 pts), transfer to another town (2 pts). At the last follow- up, 3 patients (3.6%) needed to perform transient self- catheterization (IC) due to high post- void residual volume, and the rates of bacteriuria and urinary tract infections (UTIs) were 18.9% and 7.7% respectively. Persistence’ rates were similarly higher in all the considered subgroups at the last observation period.

The results of this observational study show that patients with refractory iOAB treated with Onabot/A intradetrusor injections found a prompt benefit in terms of reduction of daily UI episodes and satisfaction to treatment. These results persisted in the long- term follow- up, with about 85% of patients continuing to ask for this kind of treatment. In previously published studies on the long- term follow- up of Onabot/A repeat injections in iOAB patients, the results appeared to be somewhat contradictory, also due to the high rate of IC requested by the patients and the rate of reported urinary tract infections (UTIs), although in the same studies the effectiveness of Onabot/A treatment has been considered to be satisfying. In comparison, at the last follow- up of our study, very few patients (3.6%) needed to perform transient IC and the rate of UTIs appeared to be low.

Significant improvements were observed in clinical outcomes and treatment’s satisfaction in all the subgroups of refractory iOAB patients receiving different numbers of Onabot/A injections, although patients’ satisfaction to treatment was higher during the first years from the beginning of treatment. Persistence’ rate was high in the long- term follow- up. Onabot/A should be promptly offered to selected refractory iOAB patients as it allows obtaining quick and successful results.

Giannantoni A, Proietti S, Costantini E, Gubbiotti M, Rossi De Vermandois J, Porena M. OnabotulinumtoxinA intravesical treatment in patients affected by overactive bladder syndrome: best practice in real-life management. Urologia. 2015;82(3):179-83.