Debate over importance of new carbidopa-levodopa agents
New therapies that offer a better
way of delivering carbidopa/levodopa were the biggest clinical advance in
Parkinson's disease, according to a plurality of experts contacted by MedPage
Today. But the responses fell short of a consensus.
Rytary, an extended release form
of carbidopa/levodopa, and Duopa, which delivers these agents using a small
portable infusion pump, was approved by the FDA in January 2015.
The new therapies were chosen as
part of the responses of 55 neurologists asked to pick a
"game-changer" in their subspecialty. The most popular selections (or
lack, in one case) in each of five major neurology fields were:
1. MS: Ocrelizumab results in
ORATORIO and OPERA I and II
2. Stroke: Publication of five
trials confirming the efficacy of neurothrombectomy for acute ischemic stroke
3. Parkinson's disease: New
formulations for delivering carbidopa/levodopa
4. Sleep: SERVE-HF trial showing
adaptive servoventilation (ASV) increased mortality
5. Alzheimer's disease: no
clinical advance stood out
Several of the specialists we
contacted agreed that Rytary was a significant advance. "Substituting
Rytary, a long-acting form of carbidopa-levodopa, for standard
carbidopa-levodopa, reduces fluctuations and 'off' time, keeping people in the
'on' state for more of the time," said Stephen G. Reich, MD,
the Frederick Henry Prince Distinguished professor in Neurology, University of
Maryland School of Medicine.
Robert A. Hauser, MD, MBA,
director, Parkinson's Disease and Movement Disorders Center at the University
of South Florida, said patients "may benefit from a small levodopa dose as
the capsules can be opened and the beads mixed in with food such as
applesauce."
Some felt there are
pharmacological advances to Rytary because, as Jacci Bainbridge, PharmD,
professor of clinical pharmacy at the University of Colorado, put it, the
product "allows for continuous smoother serum concentrations as opposed to
immediate release formulations... (which) keeps (the) drug in the therapeutic
window."
Duopa, an enteral suspension for
the treatment of motor fluctuations for people with advanced Parkinson's
disease, was called a "fundamentally new therapy" by David G. Standaert, MD, PhD,
John N. Whitaker professor and chair of neurology at the University of Alabama
at Birmingham. "I and others have seen some very dramatic improvements
with this approach -- it is often equivalent to what you might see with deep
brain stimulation," he said.
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Both of these treatments, in the
view of a number of experts, improve their ability to minimize "off"
time for patients. "It's a particularly welcome addition to our
armamentarium for managing motor fluctuations in PD patients who are not (or
are not yet) DBS candidates," added Matthew Swan, MD, of
Albert Einstein College of Medicine and Montefiore Medical Center in New York.
However, a number of experts were
not enthusiastic about Rytary. Alessandro Di Rocco, MD,
chief of NYU Langone Medical Center's movement disorders division, said the
clinical effect of the drug was "less than ideal" because of
"complex dose conversion tables that were often unhelpful in difficulty
identifying the correct dose." He said the "off" periods for
many patients fluctuated and were not predictable. "Many of the patients
[who] started on Rytary were later switched back to their previous older L-dopa
formulation, and often patients emphatically asked to return to their previous
drugs," he said.
And Sanjay Iyer, MD,
medical director of neurology at Carolinas HealthCare System's Neurosciences
Institute, noted a lack of data "to suggest that extended release versions
have fewer complications than immediate release levodopa, especially as it
relates to potential to develop dyskinesia, or abnormal involuntary movements,
such as writhing, and squirming."
Another advance for the year
included a 2013 finding that one expert said had made its way into practice
this year. Padraig O'Suilleabhain, MD,
of UT Southwestern Medical Center in Dallas, cited "the finding that doing
DBS surgery earlier rather than later is better in terms of quality of life and
likely overall cost, in a patient who develops motor fluctuations in their
first 5 years of PD."
Also mentioned was a small trial
with the leukemia drug nilotinib (Tasigna). Mark A. Stacy, MD, vice dean for
clinical research at Duke University School of Medicine, pointed to the small study conducted at
Georgetown, which found a benefit in multiple domains of the
disease.
http://www.medpagetoday.com/Neurology/ParkinsonsDisease/55449
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