In 2003, ScienCentral interviewed researcher Michael Kaplitt, assistant professor of neurological surgery at New York-Presbyterian/Weill Cornell Medical Center, and co-founder of Neurologix, Inc. Kaplitt and his team had gotten approval for a Phase 1 study to determine the safety of gene therapy in patients with Parkinson's disease and had performed the world's first gene therapy surgery on a patient with the disease. The findings of the completed study are published in the June 23 issue of the British medical journal The Lancet. The video to the right includes excerpts from our 2003 interview with Kaplitt. For more information on the newly published study, read on.
A Big First Step
The study reported positive results from the first ever gene therapy trial for Parkinson's disease. The clinical trial studied 12 patients, 11 men and one woman, ranging in age from 50 to 67, who had advanced Parkinson's disease. It was a "Phase 1" study, meaning it was designed primarily to test and prove that the therapy is safe. Kaplitt and his team used a harmless virus called an adeno-associated virus (AAV) as a sort of cargo ship for the corrective gene they wanted to deliver to the patient's brains. The virus carrying the gene called "GAD" (glutamic acid decarboxylase) was injected into a part of the brain called the subthalamic nucleus (STN), which usually has abnormally high activity in Parkinson's patients. This heightened activity leads to the loss of muscle control that is a hallmark of Parkinson's.
Increase in STN activity is largely due to a deficit of GABA, a major inhibitory neurotransmitter in the brain. The idea is that the GAD gene makes GABA and increasing GAD causes more GABA to be synthesized, thus helping to calm the STN over-activity typical of Parkinson's patients, and subsequently helping them regain control over their muscles.