A multi-center gene therapy trial for patients with advanced Parkinson’s disease has demonstrated reduced symptoms of progressive movement disorder, reports Andrew Feigin, MD, associate professor of neurology and molecular medicine at The Feinstein Institute for Medical Research in Manhasset, NY.

The study was designed to deliver the gene for glumatic acid decarboxylase (GAD), packaged in inert viral vectors, into an area of the brain called the subthalamic nucleus. GAD makes an important inhibitory chemical called GABA. The subthalamic nucleus is abnormally activated in Parkinson’s disease, leading to debilitating movement problems.

All participants in the study had a positron emission tomography (PET) brain scan before the surgery to confirm the diagnosis of Parkinson’s disease. Each patient in the active treatment received about a billion viral vectors.

The treated group showed a 23 percent improvement on the United Parkinson’s Disease Rating Scale (which assesses motor symptoms), compared to a 12 percent improvement in those who received sham surgery.

Their work appears in the journal The Lancet Neurology.