You
can find out more about NPF's National Medical Director, Dr. Michael S.
Okun, by also visiting the NPF Center of Excellence, University of Florida Center for Movement Disorders & Neurorestoration. Dr. Okun is also the author of the Amazon #1 Parkinson's Best Seller 10 Secrets to a Happier Life.
One of the common dreams shared by Parkinson’s disease patients
around the globe is the possibility of living a pill free existence.
One cannot blame the Parkinson’s disease patient or caregiver for
dreaming big. A single day in Parkinson’s disease shoes is likely to
reveal the need for dozens of pills administered day and night. In
many cases, pills are taken as frequently as every hour or two. If you
ask a Parkinson’s disease patient to place an entire pill regimen for
the day into the palms of their hands, there is a better than average
chance he or she will not be able to hold all of them. Previously,
there was a hope that deep brain stimulation
may have offered the highly sought after “pill free existence,” however
over two decades into its history, it is clear that in the majority of
cases, medications will still be required. There is however, another
treatment strategy on the horizon. A strategy that offers the
possibility of constant stimulation of the brain’s dopamine
receptors through the use of a continuous dopamine infusion pump
technology. In this month’s issue of Lancet Neurology the first
randomized controlled trial of a continuous pump infusion technology for
Parkinson’s disease has been published (online before print).
The trial utilized an intrajejunal (i.e. a tube inserted in the small
intestine) levodopa-carbidopa intestinal gel pump infusion strategy,
and it was designed to collect safety and effectiveness data. The study
was carefully conducted and was double blind (neither the patients nor
the raters knew what was administered) and randomized. It was conducted
in 26 centers including Germany, New Zealand, and the US. Participants
were randomized (1:1) to “immediate-release oral levodopa-carbidopa
pills plus a placebo intestinal gel infusion or to levodopa-carbidopa
intestinal gel infusion plus oral placebo pills.” It is important to
remember that everyone in the study received a pump, but half of the
patients did not receive active therapy (through the continuous pump
infusion). The authors were most interested in improving the amount of
time spent in the “off state” following 4 months of therapy. Off-time
improved by 4 hours in the pump group versus 2.1 hours in the pill
group. The amount of “on” time without troublesome dyskinesia was better in the pump group when compared to the pill group (4.1 vs. 2.2 hours).
The pump is approved and available in 43 countries. The United
States has lagged behind the world in adopting this new approach to
Parkinson’s disease therapy. However, in defense of the U.S.A. and the
FDA, prior to the publication of the current pump trial, all previous
results were based on uncontrolled evidence. The benefits of the pump
have been clearly demonstrated. In this population of fluctuating
patients, the data would suggest that the pump out-performs standard
medical therapy. The study did not enroll patients with severe
dyskinesia, and it is unclear how the continuous infusion pump will
perform in more severe and more disabled Parkinson’s disease patients.
One of the major drawbacks to the pump approach is the need for a
percutaneous gatrojejunostomy (a small feeding tube). These types of
tubes can serve as nidus points for infections and other complications,
and in the current study, device complications were present in 89% of
subjects. The complications were addressable in most cases, and were
reported as lower than in previous pump trials.
Patients should be aware that the current version of the pump
requires wearing an external device, and it also requires changing a
dopamine cassette once or twice a day. The dopamine cassettes are a
little smaller than a cellular phone, and usually last about 14-16
hours. Some patients will require two cassettes, and some will need
additional medications during the bedtime hours. The pumps require
continuous maintenance and programming by a qualified professional. The
tube connected to the stomach also requires constant monitoring for
infection.
If the continuous infusion approach receives FDA approval one
important step will be to compare its effectiveness to that of deep
brain stimulation therapy (DBS).
Patient selection for pumps versus DBS will be an immediate and critical
unmet need. One question will be whether the pump technology can help
debilitated patients with and without cognitive dysfunction who may be
excluded from DBS.
Patients should be aware that pumps are powerful symptomatic
therapies, but not cures; and in most cases the continuous infusion pump
will not address the dopamine resistant symptoms of walking, talking,
and thinking. Pumps have not been shown to delay disease progression.
The good news for the Parkinson’s disease community is that for a subset
of patients a “pill free existence” may be on the horizon.
