Parkinson's Gene Therapy Seems to Work
Patient: 'If You Didn't Know I Had Parkinson's Disease, You Couldn't Tell'
Oct. 17, 2006 -- It's been three years since Nathan Klein was the first person to get an experimental gene therapy for Parkinson's disease infused into his brain.
"Before the operation, I was a quivering mass of flesh," Klein, 58, tells WebMD. "With my medications, I am like 80% or 90% better. I am at a point right now where if you didn't know I had Parkinson's disease, you couldn't tell."
Klein is delighted with the treatment -- even though, as the first patient, he got a much lower dose than did the next 11 patients to be treated. Moreover, none of these 12 patients got the full treatment. As a safety precaution, only one side of their brains was treated.
Yet this half-treatment seems to work as well as deep brain stimulation, the best new treatment for Parkinson's disease. And it's safe, reports therapy co-developer Matthew J. During, MD, DSc, of New York-Presbyterian Hospital and Cornell Weill Medical Center.
"These results are just from treating one side of the brain; eventually we will treat both," During tells WebMD. "We hope our results will match or exceed those seen with deep brain stimulation. Even if we just match the deep brain stimulation efficacy, gene therapy would be simpler: no hardware, fewer adverse events. And we have data suggesting this protects against disease progression, so that over time you will see an additional benefit."
During reported the findings in a presentation to the 36th annual meeting of the Society for Neuroscience, held Oct. 14-18 in Atlanta. During, along with Michael G Kaplitt, MD, PhD, co-founded Neurologix Inc., the company developing the gene therapy.
A Pacemaker for the Brain
Brain degeneration in Parkinson's disease overexcites a part of the brain called the subthalamic nucleus (STN). This leads to the abnormal movements, tremor, rigidity, and gait problems that make life miserable for Parkinson's patients.
The therapy created by During and Kaplitt attaches the gene for a chemical messenger, called GAD, to a harmless virus. After infusion into the STN via a thin needle, this genetically engineered virus gets into brain cells and makes them send out GAD signals. It's a signal that tells the brain to calm down.
It doesn't work right away. It takes time for GAD levels to build up.
"Nothing happened for the first week. And then nothing happened for the second week. And then a month, and two months, and then at three months I thought I was a little better, nothing much," Klein says. "It was like watching grass grow. But about six months later, I started feeling a lot better."
During says that Klein's movement problems got about 40% better after treatment. Not all patients have done that well. But those who got the highest dose tended to get the most improvement.
One year after treatment, nine of the 12 patients showed an average improvement of 37% on a measure of Parkinson's disease severity. Five patients had between 40% and 65% improvement.
"We are encouraged the results seem to be maintained over time," During says. "When we look at the other side of the brain, the side we did not treat, we always see worsening of disease. This is a progressive disease. If we hadn't done the treatment, we would expect these patients to be doing significantly worse."