Botulinum Toxin A vs Anticholinergic Treatment of Neurogenic Overactive Bladder in Patients With Multiple Sclerosis

Overview

Botulinum toxin type A injections into the detrusor at a dose of 200 units (U) of BOTOX® are a recognized second-line treatment for the treatment of adult neurogenic lower urinary tract disorders. Anticholinergics are established as the usual first-line treatment for neurogenic detrusor hyperactivity, but are oft not sufficiently effective and have significant side effects. In patients with multiple sclerosis (MS) suffering from overactive bladder, the 200 U dose of BOTOX® is very effective but induces a risk of urinary retention in 30% of patients requiring the temporary use of self-catheterization1. At 100 U, a recent study shows the efficacy and very good tolerance of botulinum toxin A in terms of probing risk in MS patients with overactive bladder and failure of anticholinergics. Furthermore, the efficacy of anticholinergics in MS has been little studied and is also disputed. The investigators plan to test the therapeutic alternative as the first line of treatment in two groups of randomized MS patients from a homogeneous population suffering from overactive bladder: * a group testing the effectiveness of low doses of botulinum toxin type A (100 U, BOTOX®), * the other group receiving the standard anticholinergic treatment (solifenacin succinate, Vesicare®). During this pilot study, the efficacy and side effects profile of each treatment will be analyzed in order to determine the amplitudes of effect and the safety profiles in this population and in order to establish the statistical hypotheses for a subsequent randomized multicenter study. The aim of this study will be to establish the benefit of botulinum toxin at a dose of 100 U as a first-line treatment instead of anticholinergics

Botulinum toxin type A (BOTOX®) injections will performed on an outpatient basis by cystoscopy under local anesthesia. Twenty minutes after an intravesical instillation of 20 ml of 0.2% ropivacaine, the botulinum toxin is injected into the detrusor muscle using a flexible injection needle at a rate of 10 U of BOTOX® per mL (10 points of 1 mL injections). Intravenous prophylaxis (cefuroxime 1.5 g) will be performed 30 minutes before the injections. Patients in the Vesicare® arm will be given the tablets at the baseline visit to be taken once a day in the morning for 12 weeks. For this arm, there will be no antibiotic prophylaxis. Randomization will be carried out via eCRF in the secuTrial® environment with an integrated Interactive Web Response System (IWRS) function allowing the allocation of a participant to one of the two intervention groups. Randomization will be carried out using a randomization table in blocks of 2, predefined without the knowledge of the investigator, respecting a balanced allocation between the two groups, necessary given the modest number of participants in the study. The intensity of therapeutic responses for each treatment is not precisely known in this patient population. As a result, there are no reliable preliminary data which would allow the investigators to calculate under these "effect size" assumptions the necessary numbers of participants to be randomized between the two intervention groups in order to demonstrate a possible superiority of treatment by injection of BOTOX® 100 U in comparison to the reference anticholinergic treatment. The comparative study will therefore only be accessible after determining the intensity of these effects. Within the framework of a pilot study not directly comparative of the therapeutic approaches but seeking to identify the amplitude of the effects obtained independently by the two treatments, it does not appear necessary to resort to a study design with "double-dummy" to leave the patient blind to the method used. Such an approach would require the use of a sham injection by cystoscopic route in the group treated with anticholinergics and would not appear ethical in this context.