Botox-A Injection to Improve Bladder Function in Early Spinal Cord Injury (#H-20344)

Approximately 10,000 spinal cord injuries (SCI) occur each year, most of which occur in
males (80%). Many of these patients develop neurogenic bladder dysfunction (NGB)
characterized by overactivity of the detrusor muscle, termed detrusor overactivity (DO) or
detrusor hyperreflexia (DH). They can also develop detrusor external sphincter dyssynergia
(DESD), an abnormal/ uncoordinated response of the sphincter to bladder contraction. A
combination of these factors can lead to long-term complications in up to 50% of patients.
These complications include hydronephrosis, autonomic dysreflexia, vesicoureteral reflux,
nephrolithiasis, sepsis, renal insufficiency or failure and even death. Our basic
understanding of the physiology of NGB as well as the introduction of the concept of clean
intermittent catheterization (CIC) several decades ago has significantly reduced the death
rate due to renal complications in SCI patients. Nevertheless, there continues to be a
significant amount of morbidity and risk that these patients experience due to our
incomplete understanding of DESD; both its development and subsequent impact on bladder
function. We postulate that a primary drive to producing detrusor hypercontractility is the
obstruction created by increased tone within the external urethral sphincter (EUS). In
addition, we hypothesize that high-pressure obstructive voiding patterns displayed by
patients with DESD promote development of bladder wall smooth muscle hypertrophy and
fibrosis, loss of bladder compliance, and development of the complications listed above.

Most of our treatment options for neurogenic bladder in the SCI patient population aim to
reduce bladder filling pressures and obstructive voiding patterns either by reducing bladder
overactivity (i.e. antimuscarinic agents) or by decreasing bladder outlet resistance (i..e.
alpha 1-adrenergic receptor antagonists, sphincterotomy, UroLume stent placement, or
botulinum toxin injection of external urethral sphincter). However, typically treatments are
not initiated until these reflex voiding patterns have already developed. Almost all
patients with supraconal lesions, regardless of their neurological level of injury or final
voiding patterns, display areflexic bladders during the acute and subacute time period after
SCI. This time period can last anywhere from 1 month to 1 year (typically 6-8 weeks) after
which spinal reflex voiding develops. Dyssynergic voiding patterns are most common in
cervical and thoracic (supraconal) lesions while are flexic voiding patterns predominate in
lumbar and sacral conal and infraconal injuries. However, there are many exceptions to this
rule, especially in incomplete lesions, and that is why urodynamic testing is an important
component in the evaluation of every SCI patient.

Nerve Growth Factor (NGF): Role in Obstructive Uropathy: The processes that lead to
reorganization of neural pathways and emergence of hyperactive and dyssynergic voiding are
incompletely understood. Possible mechanisms underlying the neural plasticity following SCI
could involve alterations in levels of neurotrophic factors within the bladder. Nerve Growth
Factor (NGF) is a signaling protein that is thought to play a prominent role in mediating
the development of bladder reflex voiding mechanisms in various disorders of bladder
dysfunction including neurogenic and non-neurogenic bladder outlet obstruction and chronic
bladder inflammation (i.e. interstitial cystitis). Studies have found that by inhibiting
NGF's actions through immunization, enhancement of bladder hyperactivity and detrusor
sphincter dyssynergia was prevented in SCI rats. Finally, studies in SCI human patients
found that bladder hyperactivity as well as bladder NGF tissue levels was significantly
reduced by bladder BTX-A treatment.

BOTOX® (Botulinum Toxin Type A) Purified Neurotoxin Complex is a sterile, vacuum-dried
purified botulinum toxin type A, produced from fermentation of Hall strain Clostridium
botulinum type A grown in a medium containing casein hydrolysate, glucose and yeast extract.
It is purified from the culture solution by dialysis and a series of acid precipitations to
a complex consisting of the neurotoxin, and several accessory proteins. The complex is
dissolved in sterile sodium chloride solution containing Albumin Human and is sterile
filtered (0.2 microns) prior to filling and vacuum-drying.

One Unit of BOTOX corresponds to the calculated median intraperitoneal lethal dose (LD50) in
mice. The method utilized for performing the assay is specific to Allergan's product,
BOTOX®. Due to specific details of this assay such as the vehicle, dilution scheme and
laboratory protocols for the various mouse LD50 assays, Units of biological activity of
BOTOX cannot be compared to nor converted into Units of any other botulinum toxin or any
toxin assessed with any other specific assay method. Therefore, differences in species
sensitivities to different botulinum neurotoxin serotypes precludes BOTOX is approximately
20 units/nanogram of neurotoxin protein complex.

Each vial of BOTOX contains 100 Units (U) of Clostridium botulinum type A neurotoxin
complex, 0.5 milligrams of Albumin Human, and 0.9 milligrams of sodium chloride in a
sterile, vacuum-dried form without a preservative.

Botulinum Toxin (BTX-A) to treat DESD: Botulinum toxin, first isolated by van Ermengem in
1897, is the most potent biological toxin known to man. Through basic and clinical research,
clinicians have been able to transform this lethal toxin into a health benefit. BTX-A
represents a viable option in the treatment of DESD. When injected, the toxin acts at the
neuromuscular junction of the external sphincter to block vesicle transport of
acetylcholine; in essence, producing a chemical denervation. The clinical effects begin
within 2-3 days and are reversible as terminal nerve sprouting occurs within 3-6 months.

The majority of studies on DESD have examined several outcome measures following BTX-A
injection: Change in post-void residual (PVR), change in urethral pressure profile
(UPP-static or dynamic), change in bladder pressures during voiding, change in frequency or
severity of autonomic dysreflexia (AD), and change in symptoms or satisfaction of the
procedure to the patient. Once again, BTX-A treated patients' demonstrated improvements in
PVR and UPP similar to their previous study.

However, while most studies of BTX-A for DESD have documented significant reductions in
detrusor and urethral pressures as well as PVR, prior research has shown that detrusor leak
point pressure (DLPP) is the best prognostic measure for upper tract damage in neurogenic
bladder patients. This fundamental concept was corroborated by external sphincterotomy
studies demonstrating that failure to achieve a DLPP below 40 cm H2O increases the frequency
of upper tract deterioration. This finding underscores the importance that future studies
examining the efficacy of BTX treatment for DESD will utilize DLPP as an objective measure
of the procedure's success.

Preliminary Data: Effect of BTX-A on Urethral Outlet Resistance by Measuring Changes in Leak
Point Pressure. The purpose of these investigations was to evaluate the effects of BTX-A on
in vivo urethral resistance by measuring leak point pressure (LPP) with a vertical tilt
table and intravesical pressure clamp.

Female SD rats (n=8; 220-250g) were anesthetized with urethane (1.2 g/kg) and injected
intraperitoneally with either BTX-A (100u) or saline 18 hours prior to experimentation. LPP
was recorded before and after administration of the nicotinic receptor antagonist
-bungarotoxin (BGT), and the ganglionic blocker hexamethonium (HEX).

BGT significantly decreased the LPP in control animals by 46% but had no appreciable affect
in BTX-A treated animals. In comparison, BTX-A treatment decreased LPP by 47% compared to
baseline values in control animals. The ganglionic blocker, HEX, had no appreciable effect
on either control or BTX-A treated animals.

BTX-A significantly decreased the basal LPP to the same extent as BGT, confirming it's in
vivo potency at the striated neuromuscular junction. However, the fact that HEX had no
appreciable effect in either group suggests that sympathetic tone is not a prominent
component of outlet resistance in female rats, and may not be a suitable in vivo model to
describe the effects of BTX-A on urethral adrenergic pathways. Although originally designed
as a method to evaluate stress urinary incontinence in rodents, this method actually
measures the intravesical pressure during bladder filling at which urinary leakage occurs,
that is, detrusor leak point pressure (DLPP). The marked decrease in DLPP induced by BTX-A
in this animal model validates BTX-A's potential effects on DLPP in humans with DESD.

BTX-A Urethral Sphincter Injections in Humans: Sixty eight patients received urethral
sphincter injections for bladder outlet obstruction resulting from DESD or pelvic floor
spasticity. Patients' mean age was 53 (range 21-71) and the underlying pathophysiology for
outlet obstruction included: spinal cord injury (n=9), multiple sclerosis (n=32), stroke
(n=4), other (n=8), idiopathic retention/pelvic floor spasticity (n=15). Patients were
injected with 100 units of BTX-A into their external urethral sphincters under local or
general anesthesia. Postoperatively, significant decreases in maximal detrusor pressures
(81cm to 52cm H2O, p<0.05) and post-void residuals (240ml to 88ml, p<0.05) were observed
with beneficial effects lasting 3-4 months.

Significance: The significance of these experiments begins with the fact that our proposed
intervention occurs during early spinal cord injury (i.e. within 8 weeks) before pathologic
bladder reflex pathways have emerged. In addition, our proposed project would be: 1. The
largest, prospective randomized trial examining the effects of BTX-A urethral sphincter
injection for detrusor external sphincter dyssynergia (DESD) and the first to look at the
effect of BTX-A on detrusor leak point pressure (DLPP); 2. The first study to evaluate the
role that bladder outlet obstruction by DESD plays in the development of bladder
hyperactivity and the development of complications resulting from bladder dysfunction; 3.
The first study profiling bladder tissue levels of the signaling protein nerve growth factor
(NGF) during early SCI and then again once bladder hyperreflexic patterns develop, and; 4.
The first study evaluating the effect of reducing outlet resistance with BTX-A on bladder
NGF levels. If our hypotheses prove to be correct, treated patients will display less
incontinence, require lower doses of anticholinergic medication, and avoid the complications
of DESD listed earlier in this proposal. Although this study as written is of moderate
length (i.e. total 5 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. >10 years). In addition, BTX-A treatment could be extended to other
neurogenic populations suffering from DESD (i.e. Multiple Sclerosis) as well as other
conditions where bladder overactivity appears to be driven by outlet obstruction (i.e.
Benign Prostatic Hyperplasia).

Hypotheses:

1. BTX-A injection of the external urethral sphincter significantly decreases detrusor
leak point pressure (DLPP).

2. Decreased DLPP during early SCI will markedly reduce bladder tissue nerve growth factor
(NGF).

3. Reducing DLPP and bladder NGF during early SCI will diminish complications associated
with neurogenic detrusor overactivity (NDO) and outlet obstruction.

Inclusion Criteria:

- Male or Females between ages of 18-50

- Patient weighs over 111 pounds

- Patient has documented Spinal Cord Injury T10 or above Thoracic Level by ASIA Score
less than 8 weeks prior to the start of the study. Both complete and incomplete
spinal cord injuries will be included in this study.

- Ability to complete all study requirements including voiding diary and to attend all
scheduled study visits, in the opinion of the investigator

- Written informed consent has been obtained

- Patient has negative pregnancy test result if female and of child-bearing potential

- Written authorization for use and release of Health and Research Study Information
has been obtained

- Patient or family member is willing and able to perform clean intermittent
catheterization for duration of this study

Exclusion Criteria:

- Patient has received anticholinergic medication for the treatment of overactive
bladder before randomization into the study

- Patient has history or evidence of any pelvic or urological abnormalities, bladder or
urethral surgery or disease, other than neurogenic bladder related to spinal cord
injury, that may impact bladder function

- Patient has significant stress urinary incontinence, determined by patient history,
in the opinion of the investigator

- Neurogenic detrusor overactivity (greater than 10cm elevation in pdet pressure) at
baseline urodynamic screening (Day 0)

- Patient found to have significant baseline renal pathology (e.g. hydronephrosis,
stones, renal mass) at Day -7

- Patient has a history of two or more treated urinary tract infections within 6 months
of screening Day -7

- Patient has urinary tract infection defined as a bacteriuria count of greater than
105/ml conjoint with leukocyturia greater than 5hpf at screening Day -7

- Patient has asymptomatic urinary tract infection, defined as positive nitrites,
leukocyte esterase and or blood on urine dipstick reagent strip at randomization Day
0

- Patient has history of unexplained hematuria or unexplained hematuria if greater than
5 RBC's/hpf are present at screening Day -7

- Patient has active genital infection, other than genital warts, either concurrently
or within 4 weeks prior to screening Day -7

- Patient has history of interstitial cystitis, in the opinion of the investigator

- Patient has evidence of urethral obstruction, in the opinion of the investigator at
screening Day -7 or randomization Day 0

- Patient uses medications with anti-platelet or anti-coagulant effects (except
Lovenox) within 10 days of randomization Day 0. Lovenox 30mg SQ every 12 hours is
standard of care after SCI until 2-3 months post injury. Lovenox will be stopped 24
hours before and for 48 hours after each sphincter injection or bladder biopsy
procedure.

- Patient has hemophilia, or other clotting factor deficiencies or disorders that cause
bleeding diathesis

- Patient has previously been treated with any endovesical pharmacologic agent (e.g.
capsaicin, resiniferatoxin)

- Patient has had previous or current botulinum toxin therapy of any serotype for any
condition

- Patient has a known allergy or sensitivity to any components of the study medication,
anesthetics or antibiotics to be used during the study

- Any medical condition that may put the patient at increased risk with exposure to
Botox® including diagnosed myasthenia gravis, Eaton-Lambert syndrome or amyotrophic
lateral sclerosis

- Females who are pregnant, nursing or planning a pregnancy during the study or females
of child-bearing potential who are unable or unwilling to use a reliable form of
contraception during the study

- Current or previous participation in another therapeutic study within 30 days of
screening Day -7

- Any condition or situation which, in the investigator's opinion, puts the patient at
significant risk, could confound the study results, or may interfere significantly
with the patient's participation in the study