Parkinson's Patient Gets Gene Therapy
Daring Treatment Would Improve Symptoms, Slow Disease
A Risky Business continued...
And that's just one issue. What if the virus spreads through the brain, slowing down normal brain functions? Because gene therapy is still a very new technique, many unexpected consequences are possible.
That's true, Kaplitt admits. But 15 years of preparatory work -- including rat studies published last year and still-unpublished monkey studies -- convince him that the risks are acceptable.
"We've tried to build in extra safety measures," he says. "But until you do this in an actual human being, there is a risk. There is still the possibility that we will make too much [brain-slowing signal]."
The same virus used to deliver the Parkinson's gene therapy was recently used to deliver a gene to the brains of children born with a rare, fatal birth defect. Kaplitt says the virus didn't spread throughout the brain but remained where it was put -- just as he saw in animal studies.
And even though he points out the risks, Hauser is enthusiastic about the gene therapy.
"I think it is a good idea," he says.
Parkinson's Gene Therapy vs. Deep Brain Stimulation
The STN isn't a new target for Parkinson's treatments. Because it goes haywire, one idea is to surgically sever its connections to the rest of the brain.
Another idea is deep brain stimulation. This is a thin electrode implanted into the STN. Electric current sent through the electrode quiets the STN.
Kaplitt says the gene therapy should work even better than deep brain stimulation. It should not only calm the STN, but it should also make the STN send out calming signals to other brain regions involved in Parkinson's disease. This is likely to protect brain cells from getting worn out -- thereby slowing the relentless progress of Parkinson's.
These possibilities are why Hauser thinks the gene therapy is a good idea.
"A very realistic outcome to hope for is that this treatment would be similar to the deep brain stimulator," he says. "If so, it is worth the risk. The best to hope for is that this would work better than the deep brain stimulator, so that people won't fluctuate up and down. That is possible."