Urodynamic and Anamnestic Predictors for Individual Dose Adjustment of Intravesical Oxybutynin in Neurogenic Detrusor Overactivity: Results From the UPSIDE Study

Introduction

Intravesical oxybutynin (IVO) is a 2nd line treatment option for patients with neurogenic detrusor overactivity (NDO) who are not adequately managed by oral anticholinergics. The UPSIDE study aimed to identify urodynamic and anamnestic predictors for achieving a therapeutically satisfactory dose (TSD) of 1 mg/mL IVO and to evaluate treatment outcomes including continence, quality of life (QoL), adherence, and handling.

Methods

UPSIDE was a prospective, multicentre, non‐interventional, real‐world study including paediatric (age ≥ 6) and adult patients with NDO due to spinal cord injury (SCI), spina bifida (SB), or multiple sclerosis (MS). Patients switched to IVO (VESOXX) were observed for at least 3 months. The primary endpoint was achievement of a TSD. Secondary endpoints included urodynamic changes, continence, spontaneous micturition, catheter volume, urinary tract infections (UTI), QoL (SF‐Qualiveen‐questionnaire), adherence, persistence, handling, pre‐ and concomitant therapies and safety.

Results

Of 54 patients enrolled across 14 study centres, 36 formed the full analysis set, and 26 (72%) were categorized with a TSD. Older age and reduced estimated glomerular filtration rate (eGFR) were identified as predictors for TSD ( p  = 0.059; p  = 0.011, respectively). A dose adaptation was necessary for almost every second patient (47.2%). Urodynamic parameters such as p _det max and bladder compliance improved. Maximal catheter volume increased significantly from 304 to 409 mL ( p  = 0.012). Continence rates doubled (28% to 53%, p  = 0.043), spontaneous micturition increased from 33% to 42% (observed exclusively in patients with MS), daily micturition frequency decreased statistically significant from 8.3 to 4.6 ( p  = 0.008, n  = 12, n  = 14 respectively). UTIs decreased from 42% to 25%. SF‐Qualiveen improved statistically significant by 25% ( p  = 0.03). 70% of patients rated handling of the prefilled syringe as easy or very easy. Adherence and persistence exceeded 80%. No therapy‐related serious adverse events were reported.

Conclusion

VESOXX was effective in improving urodynamic parameters, continence, QoL, reduction of UTI and handling experience in NDO patients, with high adherence and no therapy‐related serious adverse events. TSD prediction is associated with older age and reduced eGFR. UPSIDE provides clinically relevant guidance for individualized intravesical therapy; however, interpretation of pressure‐based safety targets should remain cautious within the context of this pragmatic real‐world study.

Trial Registration: The UPSIDE non‐interventional trial is registered in the German clinical study registry DRKS under the number: DRKS00028775.