A new study shows that gene therapy could be a safe and effective treatment for Parkinson's disease. It also paves the way toward gene therapies for other disorders. The results of the study appear in the current issue of the medical journal The Lancet.
For the first time, doctors have injected genetic material directly into the brains of patients with advanced Parkinson's disease. The disease causes patients to experience symptoms like tremors, rigidity and inability to move. Clinical trials show that the new therapy is safe. Study participants also experienced improvement in the symptoms of the disease.
Ohio State University professor of molecular virology, immunology and medical genetics, Matthew During, led the study.
During said the goal of the study was to "treat people with advanced Parkinson's who no longer respond to drug treatment and come up with a new strategy to try and reverse the negative changes in the brain and reverse their symptoms and free them up to be able to move and walk normally again."
The therapy delivers genetic material directly into affected regions of their brains.
"We inject deep into the brain a drop of fluid that contains about 3-30 billion particles of virus," During said. "That virus contains a human gene and delivers this gene into a critical part of the brain that's involved in Parkinson's disease."
The part of the brain affected by Parkinson's disease is overactive it sends too many signals, leading to poor control of movement. The gene delivered in the new therapy allows the brain to make a molecule called GABA, which calms the overactivity.
"The brain essentially operates in two modes either go or stop," During said. "It's like a car which has an accelerator and a brake. The GABA is essentially the brake."
Once the brain can make GABA and calm its overactivity, patients experience relief from their symptoms.
The study represents an advance not only in treatment of Parkinsons disease, but also in the development of gene therapies for other diseases. The idea of gene therapy has been a subject of research and clinical trials for nearly 20 years. Nonetheless, no gene therapies are approved for use in the U.S.
"This particular trial is a major advance because it's the first really successful trial that's been published now, in the brain, of any neurological disease," During said.
Even so, he expects it will be at least 4 to 5 more years before the therapy could be approved for use.
"We need to go through a more definitively gold standard trial," he said. "This is a very promising trial but it's not controlled. We need to be a little bit cautious about overreading, overinterpreting the results."
Whereas the completed study focused on the safety of the treatment, the next stage is designed to confirm the effectiveness of the treatment. The next round of clinical trials will begin later this year.