NEW ORLEANS--(BUSINESS WIRE)--March 8,
2005--New data show the
investigational therapy tetrabenazine may be a safe and viable
treatment option for patients with hyperkinetic movement disorders who
have a prior history of depression, according to research presented
this week at the 9th International Congress of Parkinson's Disease and
Movement Disorders in New Orleans.
"Depression is common among people with Huntington's Disease,"
said Joseph Jankovic, M.D., Professor of Neurology and Director,
Parkinson's Disease Center and Movement Disorders Clinic, Baylor
College of Medicine, Houston, and lead study investigator. "These new
data show that a prior history of depression should not preclude
patients from being treated with tetrabenazine."
Previous studies have demonstrated that tetrabenazine, a
dopamine
depleter that works by selectively blocking vesicular monoamine
transporter 2 (VMAT2), improves the symptoms associated with a number
of hyperkinetic movement disorders. Clinical study investigators
believe serotonin and nonadrenaline depletion are likely mechanisms of
tetrabenazine-induced depression, which has been reported to occur in
approximately 15 percent of patients treated with the drug.
Study Design and Results
One objective of the retrospective analysis was to
provide data on
the potential relationship between pre-existing depression and
subsequent use of tetrabenazine. A total of 518 medical charts were
reviewed for men and women aged 3-87 years treated with tetrabenazine
at Baylor College of Medicine. The indications for treatment included
Huntington's Disease and other choreas (31.3%), tardive dyskinesia
(30.1%), dystonia (27.4%), Tourette syndrome (18.3%) and myoclonus
(3.7%).
Responses were assessed using a previously published
response
scale. Prior to initiation of tetrabenazine treatment, 272 patients
(52.5 %) had a documented history of depression and/or prior treatment
with antidepressant therapy. Adverse events were captured and coded
according to their relationship to the drug, as well as an existing
relationship to any pre-existing concomitant conditions, such as
depression.
Results of the retrospective analysis showed that the
percentage
of patients who discontinued treatment was not statistically different
in patients with a prior history of depression (3.3%) and those with
no prior history of depression (2.8%).
The majority of treated patients experienced marked
improvement in
their movement disorders. The mean duration of treatment was 29.7
months and the mean dosage was 62 mg/day. During tetrabenazine
treatment, 50 patients (18.4%) had an exacerbation of their depression
or required a change in antidepressant (15.4%) and 28 patients (11.4%)
experienced depression for the first time. A total of 16 patients
(3.1%) discontinued treatment due to an adverse event of depression.
Most adverse events were dose-related, temporary and
rapidly
reversed. The most frequent adverse events included drowsiness or
fatigue (27.4%), parkinsonism (11.8%), depression (9.5%), and
akathisia (8.9%). No orthostatic hypotension or new onset tardive
dyskinesia was reported. In this large cohort, the incidence of
depression as an adverse event was lower than in previously published
studies.
Hyperkinetic movement disorders, including Huntington's
Disease,
other choreas and tardive dyskinesia, are characterized by abnormal
involuntary movements.
Tetrabenazine
Tetrabenazine is available in some European markets and
Australia
as XENAZINE® and in Canada as NITOMAN® for the treatment of
hyperkinetic movement disorders. Although currently an investigational
drug in the U.S., tetrabenazine can have a profound effect on chorea,
with many patients demonstrating marked to good improvement. Side
effects can include drowsiness, insomnia, akathisia and depression.
Prestwick Pharmaceuticals
Prestwick Pharmaceuticals, Inc. is an emerging specialty
pharmaceutical company that focuses on treatments for CNS disorders.
The company has multiple product candidates in clinical development
for Huntington's Disease, Parkinson's disease and schizophrenia.
Prestwick recently announced positive Phase III results
of the
investigational drug tetrabenazine for chorea associated with
Huntington's Disease. The company anticipates filing a New Drug
Application (NDA) for tetrabenazine with the U.S. Food and Drug
Administration (FDA) in the near future. Prestwick was granted both
fast track and orphan designation by the FDA for tetrabenazine as a
therapy for chorea associated with Huntington's Disease.
Contact:
MCS Public Relations
Ginger H. Simms, 800-477-9626
Onsite ICPDMD: 908-531-7690
gingers@mcspr.com
