Gene therapy treatment for Parkinson’s

Gene therapy could help thousands of Parkinson’s disease sufferers, after a study found it significantly improved motor function in patients.

A trial found that injecting the glutamic acid decarboxylase (GAD) gene directly into the brain could help patients who had not responded to any other drug treatment.

The findings, published in medical journal The Lancet Neurology, show the potential of gene therapy to alleviate the symptoms of other brain disorders as well.

The GAD gene produces a brain chemical called GABA, which is responsible for coordinating movement and is severely reduced in Parkinson’s patients.

Parkinson's disease

In the treatment being tested, the gene is inserted into a part of the brain called the subthalamic nucleus with the aim of increasing GABA production and thus restoring motor function.

Significant improvements in motor function were observed in patients who underwent the gene therapy and who had been off their medication for 12 hours.

Six months after surgery, patients who had received gene therapy had an average 23.1 per cent improvement in motor function compared with 12.7 per cent in a group that had received placebos.

All patients survived the surgery and had only mild side-effects related to the treatment, such as headaches and nausea.

Patients given gene therapy also showed improvements in other clinical assessments of their main motor symptoms, especially those resistant to drug control in advanced Parkinson’s disease.

The scientists behind the randomised, double-blind gene therapy trial, Andrew Feigin and colleagues from the Feinstein Institute for Medical Research in New York, said: ‘This study … justifies the continued development of AAV2-GAD for treatment of Parkinson’s disease … and shows the promise of gene therapy for other neurological disorders.’

Parkinson’s UK offered a cautious welcome to the findings.

Dr Michelle Gardner, research development manager at the charity, said: ‘This research shows the promise of gene therapy for neurological conditions like Parkinson’s. But further research is still needed.

‘We still don’t know for how long the benefits of this treatment may last or whether there may be long-term problems due to introducing viruses into the brain.

‘In addition, any new treatment must be shown to be more effective than those currently available for Parkinson’s, which this treatment has not yet been shown to be.

‘We are passionate about innovative new research to find a cure for Parkinson’s.’

The main symptoms of Parkinson’s disease, which predominantly affects older people, are slowness of movement, shaking and stiffness of muscles.