Gene therapy treatment offers Parkinson's relief

By Maggie Fox, Health and Science Editor

WASHINGTON (Reuters) - Two studies published on Thursday offer new hope for Parkinson's disease -- one using gene therapy to treat the symptoms and another investigating a drug that might stop the incurable disease in its tracks.

While both are in early experimental stages, each takes a new approach to treating the devastating brain condition, which affects millions of people globally.

In the gene therapy trial, Dr. Michael Kaplitt of New York-Presbyterian Hospital/Weill Cornell Medical Center and colleagues used a harmless virus called an adeno-associated virus to carry a new gene into the brains of 11 volunteers with advanced Parkinson's disease.

They found it had no ill effects and appeared to reduce their symptoms, and the benefits lasted for four years in some.

"These exciting results need to be validated in a larger trial, but we believe this is a milestone -- not only for the treatment of Parkinson's disease, but for the use of gene-based therapies against neurological conditions generally," Kaplitt said in a statement.

The idea behind gene therapy is to replace faulty genes or augment the activity of beneficial genes. In the past the approach has had mixed success. In one trial in 1999 one patient died, while in another two people developed leukemia as a result of such treatment.

In the latest attempt, the gene that was delivered to the Parkinson's patients controls production of an enzyme called GAD or glutamic acid decarboxylase. GAD controls a neurotransmitter or message-carrying chemical called GABA.

GABA calms overactive neurons, and its production is lost in Parkinson's. This helps cause some of the jittery and shaky movements that mark the disease.