Parkinson's symptoms improve with Neurologix gene therapy

In this first successful double-blind clinical trial, surgeons injected Parkinson's patients' brains with a gene that improved their movement control by 23%.
Written by Janet Fang, Contributor

Gene therapy for Parkinson’s disease got its first successful double-blind clinical trial, helping patients walk and move with improved ease.

In this neurodegenerative condition, certain areas of the brain become overstimulated, while neurons in the circuits that make dopamine become strained and die. Because dopamine is important for movement control, patients often have tremors, sluggish movements, and rigidity.

About 1.5 million people in the US have Parkinson’s. Many are treated with levodopa to regain control of their movements, but they become less sensitive to the drug over time (and it has psychological and physical side effects).

Gene therapy, which targets specific genes, could offer a longer-lasting solution, according to study leader Andrew Feigin from the Feinstein Institute for Medical Research.

The trial involved 45 patients between 30 and 75 years old and was double-blind, meaning neither patients nor staff (except surgeons) knew who was receiving the therapy and who was getting a placebo.

It was funded by Neurologix, which holds the patent for the method and plans to develop it.

Half of the patients had their brains infused with a virus engineered to deliver a particular gene into the brain region that’s overactive. That gene codes for the enzyme glutamic acid decarboxylase (GAD, pictured), quieting neurons in that area.

The gene acts like a factory, pumping out one of the brain chemicals lacking in people with the disorder to rebalance the substances that stimulate and inhibit activity, says Michael Kaplitt of Neurologix.

Six months later, the researchers measured improvements in the patients by looking at their gait, posture, and hand and finger movements.

  • Patients who received gene therapy showed a 23.1% improvement.
  • The other patients, who underwent ‘sham’ brain surgery, showed a 12.7% improvement.

"Not only is gene therapy a very novel treatment," says Feigin, "but in this study it was safe and well-tolerated. That to me is a big deal that really opens up the field."

Another treatment for Parkinson's – called deep brain stimulation (DBS) – uses electricity to silence the neurons in the same region and it offers different benefits. Unlike gene therapy, DBS can be tuned up or down depending on a patient's current condition.

"Some patients might not want hardware in their brain, or others want tried and true methods," Feigin says. "Some want state-of-the-art.” Costs for both may be similar.

Neurologix CFO Marc Panoff says that the company will seek permission from the Food and Drug Administration later this year to conduct a larger clinical trial. No gene therapy has been approved by the FDA yet.

The research was reported in The Lancet Neurology this week.

Image: GAD via wiki

This post was originally published on Smartplanet.com

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