OnabotulinumtoxinA (onaBoNT-A) Versus Oral Oxybutynin ER

Current treatment of neurogenic bladder dysfunction (NGB) is limited by the suboptimal results achieved using standard antimuscarinic agents. A prominent role for the actions of alternative transmitters/growth factors in peripheral micturition pathways is emerging from the growing number of pharmacologic and localization studies in humans. For example, recently published data demonstrates a significant increased expression of Nerve Growth Factor and chemokine/cytokine levels in patients with detrusor overactivity and NGB. Treatment with onabotulinumtoxinA (onaBoNT-A) not only was shown to reduce detrusor overactivity and improve urinary symptoms but also significantly reduced tissue and urine levels of factors such as NGF. Up to this point, no study has directly compared the effects of front-line therapy of antimuscarinic agents versus onaBoNT-A on urinary symptoms in patients with NGB resulting from spinal cord injury (SCI). In addition, no investigation has examined the effects that antimuscarinic agents or onaBoNT-A have on urinary levels of NGF and chemokines/cytokines, whether changes in urinary levels predict a clinical response or a return in symptoms, and if changes in urinary levels predate changes in clinical response.

Access to selective and reliable urine testing of NGF and chemokines/cytokines provides the unique opportunity to assess the impact that modulating these agents has on bladder function. The main purpose of this proposal is to incorporate novel urine biomarker testing into existing clinical methodologies in order to: 1) evaluate the safety and efficacy of 200 U onaBoNT-A injected into the detrusor versus oral oxybutynin for the treatment of urinary incontinence (UI) caused by neurogenic detrusor overactivity (NDO) in spinal cord injured patients and 2) to determine the potential role of urine biomarkers in guiding the process of patient selection and identify surrogate predictors of treatment outcomes.

This will be a double-blind, randomized, placebo-controlled, parallel-group study to assess the safety and efficacy of onaBoNT-A or 10 mg twice a day of oral oxybutynin hydrocholoride in spinal cord injured patients diagnosed with neurogenic detrusor overactivity.

Volunteers will include both males and females with spinal cord injuries who are 18 to 80 years of age.

Volunteers will be randomized using a blocked randomization approach to either:

ARM 1: onaBoNT-A 200 U bladder injection and placebo oral capsule daily or

ARM 2: Placebo bladder injection (saline) and oxybutynin ER 10mg capsule twice a day.

Subjects will be randomized into one of the two treatment arms, using a block size of 4. The order in which the treatments are assigned in each block is randomized and this process is repeated for consecutive blocks of subjects until all subjects are randomized. This process ensures that after every fourth randomized subject, the number of subjects in each treatment group is equal.

There will be five study visits over approximately 6-7 months.

The significance of these experiments begins with the fact that our proposed intervention is the first randomized clinical trial comparing the effects of onaBoNT-A (onabotulinumtoxinA) bladder injection versus anticholinergic medication for detrusor hyperreflexia (DH). In addition, this is the first study profiling urine levels of the signaling protein nerve growth factor (NGF) and chemokines/cytokines as possible bio-markers of bladder overactivity in patients with neurogenic detrusor overactivity. Finally, this is the only study to date comparing the effects that onaBoNT-A or anticholinergic medications have on urine NGF and chemokine/cytokine levels. If our hypotheses prove to be correct, the significance to treating patients with spinal cord injury with botulinum toxin A will be less incontinence, the requirement of lower doses or avoidance of anticholinergic medication and its associated side effects, and the ability to prevent the complications of DH/DESD (Detrusor-External Sphincter Dyssynergia) including urinary tract infections, decubiti, and impairment of quality of life. Although this study as written is of moderate length (i.e. total 4 years), we hope that by finding significant results, we will be able to capture a longitudinal history of this population by extending follow-up to a longer duration (i.e. over 10 years).