Efficacy of intravesical oxybutynin in children with neurogenic bladder dysfunction: A randomized, prospective controlled multi-center trial.

The primary objective of this study is to compare the **efficacy** of intravesical oxybutynin instillation versus placebo in increasing maximal bladder capacity in children with overactive neurogenic bladder due to **spina bifida**. This is particularly relevant for patients who perform intermittent catheterization and for whom oral anticholinergic treatment is ineffective or poorly tolerated. The primary outcome is clinically significant as it addresses a critical need for effective management of bladder dysfunction in this patient population, potentially improving their quality of life and reducing the risk of renal complications.

Secondary objectives include:

• Evaluating the evolution of maximum bladder pressure and time to clinical treatment failure as perceived by the patient, which are considered objective markers of neurological bladder improvement.
• Comparing the tolerance and adverse effects of the treatment between groups.
• Assessing the number of responders and continent patients post-treatment.
• Evaluating the usability of intravesical oxybutynin.
• Comparing the evolution of quality of life and bladder diary data between groups.
• Assessing the evolution of other urodynamic parameters and renal ultrasonography parameters.
• Identifying patient characteristics associated with a greater probability of response to intravesical oxybutynin.

The clinical trial involves a study population of children aged between **6 and 17 years** who are diagnosed with **overactive neurogenic bladder** due to **spina bifida**. The trial includes both male and female participants, and the population is considered vulnerable. Participants are required to have been performing intermittent catheterization for at least six weeks, with a frequency of at least three times a day. The trial targets individuals for whom oral anticholinergic treatment is ineffective or poorly tolerated. Participants must have undergone renal ultrasonography within the last two months and cystomanometry within the last six months. The sponsor has not provided the total number of participants involved in the study. The selection criteria include being affiliated with or a beneficiary of a social security plan and having given informed consent to participate. The trial does not specify any particular lifestyle considerations such as diet or physical activity.

The clinical trial is designed to evaluate the **efficacy** of intravesical oxybutynin in children with neurogenic bladder dysfunction, specifically those with spina bifida. This is a randomized, prospective, controlled, multi-center trial. The primary objective is to compare the efficacy of intravesical oxybutynin instillation versus placebo in increasing maximal bladder capacity in children who perform intermittent catheterization and for whom oral anticholinergic treatment is ineffective or poorly tolerated. The trial is expected to commence on January 1, 2025, and conclude by May 3, 2027.

Participants will undergo a series of study visits, beginning with an inclusion (screening) visit to confirm eligibility based on criteria such as age (6-17 years), previous renal ultrasonography, and cystomanometry results. Following the screening, participants will be randomized to receive either the active treatment or placebo. The trial will include follow-up visits at regular intervals to monitor the evolution of maximal bladder capacity and pressure, as well as to assess the safety and tolerability of the treatment. The primary endpoint will be evaluated at the end of a 4-week treatment period, with secondary endpoints including the time to clinical treatment failure and the proportion of responders.

The expected length of participant involvement is approximately 4 weeks, with conditions for early termination including intolerable side effects or a lack of efficacy as judged by the patient or practitioner. Participants will be required to perform intravesical catheterization and instillation, with the study assessing usability and quality of life changes through standardized questionnaires. The trial will adhere to rigorous scientific standards to ensure the reliability and validity of the results.

The clinical trial involves the administration of **VESOXX 1 mg/ml**, an **intravesical solution** containing **oxybutynin hydrochloride** as the active substance. This pharmaceutical form is specifically designed for intravesical use, meaning it is directly instilled into the bladder. The solution is manufactured by FARCO-PHARMA GMBH and is authorized under the marketing authorization number BE533822. The maximum daily dose of VESOXX is 30 mg, with a total dose not exceeding 0.4 mg/kg. The treatment period is limited to a maximum of 28 days. The administration schedule and participant compliance are monitored to ensure adherence to the dosing regimen.

The comparator treatment in this study is a **sterile 0.9% NaCl solution** used for intravesical instillation, serving as a placebo. This solution does not contain any active pharmaceutical ingredients and is used to evaluate the efficacy of the experimental treatment against a non-active control. The placebo is administered in the same manner as the experimental drug, ensuring that the route and frequency of administration are consistent across both treatment arms. Compliance with the placebo administration is similarly monitored to maintain the integrity of the trial results.

The efficacy of intravesical oxybutynin in children with overactive **neurogenic bladder** due to spina bifida will be assessed through a randomized, prospective controlled multi-center trial. The primary endpoint for evaluating efficacy is the evolution of maximal bladder capacity at 4 weeks of treatment, marking the end of follow-up. Secondary endpoints include the evolution of maximal bladder pressure at 4 weeks, time to clinical treatment failure, and evaluation of tolerance and side effects. Additional secondary endpoints involve the proportion of responders and continent patients at 4 weeks, product usability, and standardized differences in patient quality of life. These will be measured using the ICIQ-UI-SF and KIDSCREEN-10 scores. The trial will also assess the evolution of elements from the bladder diary, urodynamic assessments, and renal ultrasonography at 4 weeks of treatment. Data collection will occur at specified timepoints, including the number and volume of urinary catheterizations over 72 hours during the week preceding each visit. The trial aims to provide comprehensive insights into the efficacy and safety of intravesical oxybutynin for this patient population.