Silver Lining for Parkinson's Disease
Gene Therapy for Parkinson's No Longer Science Fiction
June 21, 2007 - A gene therapy for Parkinson's disease does no harm and may
help, paving the way for a clinical trial that could revolutionize treatment, a
small new study shows.
There's evidence that the treatment works -- including the
testimonial of Nathan Klein, the first patient to receive the gene therapy.
But these findings come only from an early test of the treatment in 12
patients. It will take larger clinical trials to prove the treatment really
That having been said, the early results -- appearing in the June 23 issue
of The Lancet -- are very promising, says Michael Kaplitt, MD, PhD,
associate professor of neurological surgery and director of movement disorders
surgery at New York Presbyterian Hospital/Weill Cornell Medical Center.
"There was no toxicity whatever, no matter how you look at it,"
Kaplitt tells WebMD. "When we started this, there were those who suggested
we might do great harm to patients. Yet at the highest dose we were injecting
35 billion of these particles into the brain, and not a single patient had even
Moreover, there's preliminary evidence the treatment works, says Kaplitt,
who is a co-developer of the treatment with colleague Matthew J. During, MD,
DSc. During is now with Ohio State University. They founded a company,
Neurologix, to develop the treatment.
Gene Therapy for Parkinson's
The gene therapy calls for injection of a genetically engineered virus deep
into the brain -- into a region called the subthalamic nucleus or STN. During
Parkinson's disease, the STN becomes wildly overactive. The virus gets into
brain cells and causes them to make a chemical signal that calms the STN.
Parkinson's disease affects both sides of the brain. But for safety's sake,
regulators insisted that Kaplitt and colleagues test the gene therapy on only
The result: Improvements were seen on the side of the body controlled by the
treated part of the brain. Improvement began three months after treatment and
lasted for a year in most patients.
"Some patients did dramatically better, some did less well. After one
year, 10 of the 12 patients were better than they were at [the beginning],"
Nobody threw away their Parkinson's medications. But the patients who did
best had fewer Parkinson's symptoms, even in the "off" state between
doses of medication.
This proves nothing, Kaplitt is quick to say, because untreated Parkinson's
patients fluctuate wildly. A larger study -- in which both sides of patients'
brains will be treated -- is likely to start later this year.
But the work has already moved gene therapy from the world of science
fiction to the world of clinical trials, says Parkinson's expert Karl Kieburtz,
MD, professor of neurology at the University of Rochester in New York.
"If you or a family member have Parkinson's disease, and you are
interested in participating in research, gene therapy is one of the treatments
you will now be approached about," Kieburtz tells WebMD. "Gene therapy
is coming from the fringe to the mainstream. It is good for patients and their
families to know this is emerging now."
For Kaplitt, it's the exciting culmination of years of research.
"The world is changing for patients with neurodegenerative
diseases," Kaplitt says. "If they have early or even moderate disease,
over the course of their illness this and other things coming down the line
hold promise -- not just for future generations, but for them in their
Meanwhile, Kaplitt says, Nathan Klein is still doing well.