NeuroTalk Support Groups - Spheramine Update

the following update was publised in April 2008 in Neurotherapeutics: The Journal of the American Society for Experimental NeuroTherapeutics. It contains some promising information. Note that the improvement of the conditions of the six patients involved in the first study is continuing even 4 years after the surgery. The article contains several pages. As I have no link I will provide here the full text without the tables.

Spheramine for Treatment of Parkinson’s Disease
Natividad P. Stover and Ray L. Watts
Department of Neurology, The University of Alabama at Birmingham, Birmingham, Alabama 35294

INTRODUCTION
Parkinson’s disease is a progressive neurodegenerative
disorder, characterized by a constellation of motor and nonmotor
symptoms. The cause of PD is probably multifactorial
and related to both genetic and environmental factors.
The pathologic diagnosis includes dopaminergic cell loss in
the pars compacta of the substantia nigra and the presence
of lewy bodies.1,2 The cardinal motor symptoms of PD
include tremor, bradykinesia, stiffness, and postural changes,
3 and improve significantly with oral administration of
dopaminergic medications in the majority of patients.4 Progression
of the disease makes the response to oral dopaminergic
medications more unpredictable, and most patients
develop motor complications. Ablative surgery or deep
brain stimulation may also improve the motor symptoms, as
well as improving some of the complications related to
pharmacologic therapy.5–7 At least some aspects of the
motor complications that appear in many patients after
long-term pharmacologic treatment of PD are thought to be
related to the pulsatile administration of the dopaminergic
medications.8 Continuous systemic administration of dopaminergic
agents may prevent or delay the occurrence of
these disabling side effects.9,10 Numerous therapeutic clinical
trials since the 1980s have attempted to address the
problem of dopamine delivery and tried to develop more
physiologic replacement of dopamine to treat PD.11–13
To date, more than 300 patients have been treated worldwide
with stereotactic implantation of dopamine-producing,
allogeneic human fetal mesencephalic tissue, with conflicting
results. Nonetheless, treatment has provided promising
learning experiences and valuable information.14–27 Similar
types of limitations were also encountered with xenotransplantation
of porcine fetal mesencephalic cells. Spheramine
therapy does not require the use of immunosuppression, and
has advantages regarding the ethical and logistical problems
associated with the use of human fetal brain tissue.

PROPERTIES OF SPHERAMINE:
BIOLOGICAL, PHARMACOLOGICAL, AND
TECHNOLOGICAL
Human RPE cells are support cells derived from the
inner layer of the neural retina,28–30 located between the
photoreceptor and the choriocapillaris layers. These cells
form tight junctions that contribute to maintaining the
blood–brain barrier and provide a physical barrier to activated
immune cells. The cells grow to confluence during
the formation of a stable retinal structure and survive the
lifetime of the individual, providing also a trophic function
to the retina. Human RPE cells for transplantation are isolated
from postmortem human eye tissue acquired from
human eye banks; they can be expanded in tissue culture
and can be stored for prolonged periods of time.31 In this
way, a single donor eye can potentially treat many patients.
Melanin, the pigment present in hRPE cells, has important
physiologic functions.32 Melanin is able to absorb
and block light coming through the sclera, protecting
the retina from light damage and improving the
quality of images. Levodopa is a precursor in melanin
production in hRPE cells, and during the process of
melanogenesis the hRPE cells express both levodopa and
small quantities of dopamine.33 In the biosynthesis of
melanin, tyrosine is hydroxylated to levodopa by tyrosinase
and this is converted to intermediates that polymerize
to form melanin.
The immune privilege associated with the anterior
chamber of the eye is thought to be related to the expression
by hRPE cells of detectable levels of the Fas
ligand protein,34,35 which prevents apoptosis when attached
to a substance, a characteristic that may contribute
to the survival of hRPE cells implanted into the
brain.36,37
Human RPE cells also express retinaldehyde binding
protein, cytokeratins, vesicular monoamine transporter,
platelet derived growth factor, and epidermal and vascular
endothelial growth factors, which contribute to support and
trophic functions of hRPE cells in the retina.38,39
The technological basis of Spheramine is the combined
use of hRPE cells in attachment to biologically
compatible gelatin microcarriers that have a diameter of
about 100 m (FIG. 1). Microcarriers have been frequently
used in transplantation therapies and tissue engineering
in recent years.40–52 The microcarriers present
in Spheramine allow prolonged survival of the cells in
the absence of immunosuppression, prevent apoptosis,
and maintain the cells in a monolayer distribution, which
is important in the case of hRPE cells for the process of
melanization. Human RPE cells unattached to microcarriers
do not survive well in the brain, and do not produce
a lasting therapeutic effect in PD models.53
The tissue for the preparation of Spheramine is acquired
from eye donors with negative test results for bacterial and
viral infections. The isolated hRPE cells are expanded under
current good manufacturing practices (cGMP) conditions
and are prepared and tested for sterility. The cells are
also examined for the presence of viral particles with the
use of transmission electron microscopy. The microcarriers
are prepared from certified porcine gelatin, processed with
steam for sterilization, and prepared under cGMP conditions
(FIG. 2).
The sterility of Spheramine is confirmed by Gram
stain in the laboratory at the clinical site, and it is placed
in Hank’s Balanced Salt Solution (HBSS). The cells are
tested for viability and counted before being loaded into
syringes for implantation.

Preclinical human studies
Studies in vitro and in accepted animal models of PD
were conducted to determine the biochemical, toxicological,
and pharmacological properties of Spheramine and
its components before the development of the human
phase studies.54 The studies were also directed to determine
the dose of Spheramine that was clinically effective
in parkinsonian nonhuman primates, and these data were
used to calculate the number of cells to be implanted in
the human studies.
The preliminary efficacy of hRPE cells was determined
initially in the PD animal model of unilateral
6-hydroxydopamine (6-OHDA) striatal-lesioned rats.55
The animals received approximately 1000 cells attached
to 150 microcarriers in the ipsilateral lesioned striatum.
The animals exhibited significant reduction in apomorphine-
induced circling after the implantation, a pharmacological
effect indicating an increase of dopaminergic
stimulation. This effect was maintained for the duration
of the 18-week study, without using immunosuppression.
Implantation of hRPE cells unattached to microcarriers
produced only a brief, transient effect in the animals.56
A controlled, blinded study was performed to assess
the effect of intrastriatal implantation of hRPE cells on
gelatin microcarriers in MPTP-induced hemiparkinsonian
Maccaca mulatta monkeys. The animals that were
implanted with approximately 250,000 hRPE cells on
gelatin microcarriers over five sites in the lesioned striatum
had statistically significant motor improvement at
12 months after implantation, compared with control
animals. The animals implanted with a low dose of cells
(50,000 with microcarriers) or with microcarriers alone
did not show significant improvement of symptoms.53
As part of the toxicology studies, the Ames test Salmonella
typhimurium reverse mutation assay,57,58 an accepted
test that studies mutagenic effects, showed no
mutations when used with Spheramine. A toxicological
study with intracranial implantation of gelatin microcarriers
or Spheramine was done in M. fascicularis monkeys
to estimate the maximally tolerated total dose of Spheramine
or of the gelatin microcarriers alone. To test the
related mortality or body weight effects, gelatin microcarrier
beads were implanted intracranially in M. fascicularis;
histopathological examination of the brain in these
animals showed only mild astroglial cell proliferation
and inflammation, with no evidence of granulomatous or
immune-mediated reactions.

Phase I study
The first study in humans evaluated primarily the
safety and tolerability of Spheramine in an open-label,
single-center, pilot study in six patients with advanced
PD. The exploratory evaluation of efficacy focused on
motor disability. All the patients had bilateral but asymmetric
PD, moderate to severe motor symptoms, motor
fluctuations, and dyskinesias of varying degrees; all were
levodopa responders. The patients were placed on optimal
antiparkinsonian medications and the doses were
maintained stable for at least 3 months before the surgery.
The patients had baseline evaluations 1 month before
surgery in the off state as practically defined—that
is, in the morning after at least 12 hours overnight without
taking medications. All the patients had normal findings
on magnetic resonance imaging (MRI) prior to surgery.
The mean age of the patients was 52 years (40 –70),
and they had a mean PD duration of 10 years. The Hoehn
and Yahr stages were 3–4 in the off state and 2–3 during
the on state.
Surgery was done using MRI stereotactic guidance to
target the postcommissural putamen. A burr hole was
made anterior to the coronal suture with the patient under
general anesthesia and in the supine position. A total of
approximately 325,000 hRPE cells on gelatin microcarriers
in 250 L were implanted unilaterally in five tracts
in the postcommisural putamen, contralateral to the patient’s
more affected side. The tracts were spaced 5 mm
apart, and in each tract there were two deposits of 25 L
separated by 5 to 10 mm in each target. The patients were
taken to a recovery room and then transferred to a hospital
bed and discharged within 3 days, after a brain MRI
confirmed accurate placement of the implants.59
The safety and tolerability evaluations consisted of
clinical and neurological examinations, recording of side
effects, vital signs, and standard laboratory studies at 1,
3, 6, 12, 24, 36, and 48 months after surgery, as well as
periodic brain MRI and neuropsychological evaluations.
60 The patients tolerated the implantation well, and
there were no serious adverse events related to the treatment.
One patient had a small hemorrhage (4 7 mm)
that was asymptomatic immediately after the surgery and
subsequently resolved. One patient had an episode of
depression with suicidal ideation at 14 months after surgery
that required admission to the hospital; this was
treated medically and improved in the subsequent weeks.
The most frequent side effect was transient headache
immediately after the surgery in the six patients, which
resolved spontaneously in 1 to 2 weeks The adverse
events that were considered as possibly or probably related
to the treatment were transient increases in peakdose
dyskinesias (in four of the six patients), which were
mild, and the appearance of visual hallucinations without
previous episodes (in three of the six patients). Both side
effects resolved after reducing the antiparkinsonian medications.
One patient reported increased freezing episodes
at 7 months after implantation. There were no
significant changes in laboratory assessments.61
The exploratory primary efficacy outcome measure
was the change from baseline in the Unified Parkinson
Disease Rating Scale (UPDRS) during the practically
defined off state. The results showed a clinically and
statistically significant improvement from baseline in the
UPDRS motor off state score in all six patients. The
mean improvement was a 48% reduction of the off state
in the UPDRS motor disability score at 12 months, which
was sustained through 24 months (with an average improvement
of 41%). This improvement was maintained
at 43% at 48 months in five of the six patients; the sixth
patient refused to be off the PD medications overnight.
The UPDRS motor off state score improved from mean
( SD) of 52 9 at baseline to 27 7 at 12 months, 31
7 at 24 months, and 28 5 at 48 months (FIG. 3).
The clinical motor improvement was more evident
contralateral to the implanted striatum. On state time,
measured using patient diaries,62 increased from 44% of
the awake day at baseline to 55% at 12 months, 65% at
24 months, and 53% at 48 months after surgery. The off
state duration of the awake day decreased from 41% at
baseline to 30% at 12 months, 28% at 24 months, and
35% at 48 months (n 5 patients) (FIG. 4). Total
UPDRS scores decreased from 118 14 mean at baseline
to 69 10 at 48 months. There was no increased on
state time with dyskinesias, and no off state dyskinesias63
were observed. The section of the UPDRS regarding
mentation, behavior, and mood was maintained stable
during the 4 years of follow-up. Scores on the PD
Quality of Life Questionnaire (PDQ-39)64–66 improved
from a mean of 42 11 at baseline to 26 12 at 12 and
at 24 months and to 29 20 at 48 months (Table 1).

Phase II study
Based on the results of the human phase I clinical trial,
a phase II study was initiated and the surgeries have just
been completed. This trial was a double-blind, randomized,
multicenter, placebo (sham-surgery) controlled
study of the safety, tolerability, and efficacy of Spheramine
implanted bilaterally into the postcommissural putamen
of patients with advanced PD. To maintain the
blind, the surgical procedures were performed by a neurosurgeon
located at a medical center geographically
separated from where the patient was evaluated. The
study was designed to include three cohorts. In the first
group there were 12 patients, with 6 assigned to active
treatment and 6 to sham surgery. The second cohort
comprised 24 patients, and a new review of the accumu-
lated safety data was done before proceeding to the third
cohort. A total of 71 patients underwent surgery.
The primary efficacy endpoint of the study was the
change in the UPDRS motor subscore during the off state
after 12 months, compared with baseline. Secondary
endpoints included the change in total UPDRS scores,
UPDRS motor subscores during the on state, UPDRS
activities of daily living scores, quality of life scores
(PDQ-39), and evaluation of dyskinesias.
The candidates were evaluated and their medications
optimized 3 months before the surgery. The inclusion
criteria required that the patients have disease duration of
more than 5 years, be in the age range from 30 to 70
years, have bilateral disease, and have insufficient symptom
control or intolerable side effects with best medical
treatment. Patients were excluded from the study if they
had PD with only tremor-based symptomatology, severe
dyskinesias, significant psychiatric or cognitive symptoms,
or severe or uncontrolled systemic disease. The
patients were required to have at least 33% improvement
in the UPDRS motor score between the practically defined
off and on state at the screening visit, and the scores
had to be between 38–70 points. Also, patients were
required to have unequivocal clinical on and off periods.
The patients were randomized to receive either bilateral
stereotactic implantation of Spheramine into the
postcommissural putamen (325,000 cells per side) or
sham surgery. The patients were evaluated every 2 weeks
during the first month after surgery, then monthly for 3
months, and then every 3 months thereafter, up to 2
years. The selection of the dose of 325,000 cells was
based on the animal studies, as well as the dose used in
the open-label human clinical study. The surgical team in
charge was unblinded only for the patients on whom they
operated. The treating neurologist, UPDRS rater, and all
other staff remained blinded. The same independent rater
evaluated each patient during all of the visits.
The safety evaluations included physical and neurological
examinations, vital signs, adverse events, electrocardiography,
laboratory parameters and periodic brain
MRI and neuropsychological assessments. The regimen
of medications was maintained stable for at least the first
year, unless medically necessary to treat side effects or in
case of substantial deterioration of the patient’s condition.
All patients had stereotactic frame placement, followed
by brain MRI. In the operating room, the patients
received anesthesia appropriate to make them unaware of
the activities. The patients were randomized to Spheramine
or placebo treatment. The patients randomized to
Spheramine had bilateral scalp incisions, with burr holes
placed in the calvaria and opening of the dura. A total of
325,000 hRPE cells in a volume of 250 L distributed
along five needle tracts spaced about 5 mm apart were
stereotactically implanted into each postcommissural putamen.
Each tract had two deposits of 25 L of Spheramine
suspension placed approximately 5–10 mm apart
along the linear tract (65,000 hRPE cells per tract). The
sham surgery control patients had bilateral scalp incisions,
with burr holes placed in the outer table of the
calvaria but without opening of the dura. The duration of
the sham surgery was similar to that of the treatment
surgery.
A placebo-controlled, double blind study was chosen
to provide an unbiased evaluation of the efficacy and
safety of Spheramine in PD patients with moderate to
advanced disease.67,68 The patients treated with placebo
in this phase II trial will be eligible to receive Spheramine
if this study demonstrates satisfactory efficacy and
safety after the data are analyzed. Also, phase III studies
will follow.

CONCLUSION
Spheramine is currently an experimental approach for
the treatment of PD and the preclinical and open-label
human studies show promise worthy of further investigation.
Currently, it is postulated that the ability of hRPE
cells to produce levodopa in the biosynthetic pathway for
melanogenesis may serve as the rationale for a therapeutic
effect, but a role of trophic factors cannot be excluded.
A double-blind, controlled phase II study in advanced
PD patients is currently underway, and data from this
study will be available for analysis within 12 to 18
months. If this study demonstrates acceptable tolerability,
safety, and efficacy then a pivotal phase III trial will
be warranted.

frank_ger