Experimental Treatment Shows Early Promise

Jun 22, 07:36 AM

Current Headlines: By MALCOLM RITTER

By Malcolm Ritter

The Associated Press

NEW YORK

An experimental treatment for Parkinson's disease seemed to improve symptoms - dramatically so, for one 59-year-old man - without causing side effects in an early study of a dozen patients.

The gene therapy treatment involved slipping billions of copies of a gene into the brain to calm overactive brain circuitry.

The small study focused on testing the safety of the procedure rather than its effectiveness, and experts cautioned that it's too soon to draw conclusions about how well it works. But they called the results promising and said the approach merits further studies.

"We still have quite a bit more testing to do," said Dr. Michael Kaplitt of Weill Cornell Medical College in New York, an author of the study. Still, "the initial results are extremely encouraging."

Kaplitt and collaborators report their results in this week's issue of the British medical journal The Lancet.

They're not alone in trying gene therapy for Parkinson's. In April, another team told a medical meeting that its experiments, which delivered a different kind of gene to a different part of the brain, also appeared safe and gave a preliminary hint of benefit.

Nathan Klein, 59, a freelance television producer in Port Washington, N.Y., said the disease left him "pretty messed up." It weakened his voice, impaired his walking and made his hand tremble so badly he couldn't hold a glass of wine without spilling it all.

Klein was the first patient to be treated with Kaplitt's gene therapy procedure in 2003, and he said his symptoms gradually subsided afterward. Nowadays, he said, apart from freezing now and then when he wants to walk, the symptoms are basically gone.

"I'm elated," said Klein, who continues to take his regular pills for the disease. "It's unbelievable."

Kaplitt, who has a financial interest in Neurologix Inc., which paid for the research, noted that the 12 patients in the study still have Parkinson's symptoms.

Current medicines can control symptoms, but can't stop the disease from getting worse over time, and they can produce troublesome side effects such as uncontrollable movement.

Some patients gain relief from a surgical treatment called deep brain stimulation, in which electrodes are placed in the brain .

Kaplitt's procedure was aimed at achieving the same goal as that surgery, calming overactive circuitry in the brain. It gets overactive because it loses the normal supply of a chemical called GABA. The gene therapy was designed to make the brain produce more GABA.

For the gene therapy surgery, a dose of a virus engineered to ferry copies of a gene was delivered into cells of a brain region called the subthalamic nucleus. The gene copies enable the cells to pump out more GABA.

The Lancet paper reports that over a year, patients showed no side effects from the procedure. What's more, they showed fewer tremors, stiffness and walking problems.

The improvements were evident at a checkup three months after the procedure and persisted to the end of the study, one year after the surgery, researchers reported. By that time, the overall amount of improvement from before surgery was about 24 percent when measured at times that patients were off their normal medication, and 27 percent at times when they were on medication.

Most of the effect appeared on just one side of the body. Because of concerns about safety , the researchers treated only the brain circuitry controlling one side of the body.

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