美国国家公共电台 NPR Cancer Drug That Might Slow Parkinson's, Alzheimer's Headed For Bigger Tests

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Scientists are hoping a cancer drug can help people with two common and disabling brain diseases - Parkinson's and Alzheimer's. A small study of the drug offered hints of its potential. Now two larger and more rigorous studies are underway, as NPR's Jon Hamilton reports.

JON HAMILTON, BYLINE 1: When Jonathan Lessin was 38, he noticed that his right pinky finger had started shaking.

JONATHAN LESSIN: I went to see a neurologist, and he diagnosed with Parkinson's disease. That was 14 years ago.

HAMILTON: Parkinson's gradually kills off brain cells that control movement. But for a decade after his diagnosis 2, Lessin was able to keep working as an anesthesiologist in Washington, D.C. He retired 3 when his symptoms began to interfere 4 with his work, and now the disease has begun to affect things like his speech.

LESSIN: It's slowly progressing. My balance is getting worse and worse. I'm falling more and more during the day, but I'm still able to do things like rock climb and ski and bike.

HAMILTON: Lessin has been able to stay active thanks to treatments that help control symptoms, but the disease continues to eat away areas of his brain. So Lessin was excited to learn about a study of a drug that might slow or halt that process.

LESSIN: Well I've always been riding the leading edge of treatment, and I just figure I'd go for it.

HAMILTON: The drug is called nilotinib. It's approved to treat a form of leukemia. And 18 months ago, researchers at Georgetown University Medical Center found that small doses of the drug appeared to help a handful of people with Parkinson's disease and a related form of dementia.

Fernando Pagan is a neurologist at Georgetown. He says that tentative finding got a lot of attention because no existing drug can stop these diseases.

FERNANDO PAGAN: Our phones were basically off the hook after the press releases came out.

HAMILTON: Pagan says nilotinib seems to work by eliminating toxic 5 proteins that build up in the brains of people with Parkinson's and Alzheimer's. He says the drug activates 6 a mechanism 7 in brain cells that acts like a sort of garbage disposal grinding up bad proteins.

PAGAN: Our drug goes into the cells to turn on that garbage disposal mechanism. And if we are able to degrade these proteins, we could potentially stop the progression of this disorder 8.

HAMILTON: Potentially. To learn more about nilotinib, Georgetown has launched two studies - one for people with Parkinson's, the other for people with Alzheimer's. Pagan says the primary goal is to learn whether this powerful cancer drug is safe enough for patients with brain diseases, but the new study should also provide better evidence about whether the drug really works.

J. Paul Taylor, a researcher at St. Jude Children's Research Hospital in Memphis, says the new studies are important because the initial study gave many scientists pause.

J PAUL TAYLOR: The pause comes from the fact that it was such a small trial. There was no placebo 9 control, and it really wasn't designed to assess efficacies.

HAMILTON: Jonathan Lessin says, as a former physician, he understands those caveats 10, but as someone with Parkinson's, he sees an opportunity.

LESSIN: I'm very optimistic. I've seen it cure Parkinson's in mice. I've seen people that can talk again, walk again, which is very encouraging.

HAMILTON: And Paul Taylor says there's good reason for optimism. He says drugs like nilotinib are coming along because scientists have a better understanding of diseases like Parkinson's and Alzheimer's.

TAYLOR: If the results of this trial don't turn out to be as exciting as the very tiny trial suggested, I would not get too pessimistic because there are other developments that are in the wings.

HAMILTON: The Georgetown studies are enrolling 11 patients now and will take more than a year to complete. Jon Hamilton, NPR News.

(SOUNDBITE OF PANTHA DU PRINCE SONG, "NOMAD'S RETREAT")