First hints Parkinson's can be stopped. By James Gallagher
It may be possible
to stop the progression of Parkinson's disease with a drug normally used in
type 2 diabetes, a clinical trial suggests.
Current drugs help
manage the symptoms, but do not prevent brain cells dying. The trial on 62
patients, published in the Lancet, hints the medicine halted the progression of
the disease. The University College London (UCL) team is "excited",
but it urges caution as any long-term benefit is uncertain and the drug needs
more testing.
"There's
absolutely no doubt the most important unmet need in Parkinson's is a drug to
slow down disease progression, it's unarguable," Prof Tom Foltynie, one of
the researchers, told the BBC. In Parkinson's, the brain is progressively
damaged and the cells that produce the hormone dopamine are lost. It leads to a
tremor, difficulty moving and eventually memory problems. Therapies help manage
symptoms by boosting dopamine levels, but the death of the brain continues and
the disease gets worse. No drug stops that happening.
In the trial, half of
patients were given the diabetes drug exenatide and the rest were given a
placebo (dummy treatment). All the patients stayed on their usual medication. As
expected, those on just their usual medication declined over 48 weeks of
treatment. But those given exenatide were stable. And three months after the
experimental treatment stopped, those who had been taking exenatide were still
better off. Prof Foltynie told the
BBC News website: "This is the first clinical trial in actual patients
with Parkinson's where there has been anything like this size of effect. "It
gives us confidence exenatide is not just masking symptoms, it's doing
something to the underlying disease. "We have to be excited and
encouraged, but also cautious as we need to replicate these findings."
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They also need to
trial the drug for much longer periods of time. An effective drug would need to
hold back the disease for years in order to make a significant difference to
patients. Parkinson's progresses slowly and the difference in this 60-week
trial was definitely there, but was "trivial" in terms of the impact
on day-to-day life, say the researchers. The drug helps control blood sugar
levels in diabetes by acting on a hormone sensor called GLP-1. Those sensors
are found in brain cells too. It is thought the drug makes those cells work
more efficiently or helps them to survive.
It is why the drug is
being tested in other neurodegenerative diseases including Alzheimer's. David
Dexter, the deputy director of research at Parkinson's UK, said: "The
findings offer hope that drugs like exenatide can slow the course of
Parkinson's - something no current treatment can do. "Because Parkinson's
can progress quite gradually, this study was probably too small and short to
tell us whether exenatide can halt the progression of the condition, but it's
certainly encouraging and warrants further investigation."
Dr Brian Fiske, from
the The Michael J Fox Foundation for Parkinson's Research, said: "The
results from the exenatide studies justify continued testing, but clinicians
and patients are urged not to add exenatide to their regimens until more is
known about their safety and impact on Parkinson's."
