US:The first gene-based therapy for Parkinson's disease has been found to be effective following brain scans of patients who received the treatment as part of an ongoing trial.
The success marks an important landmark for gene therapy, which has never before been used to treat a degenerative brain disease in humans.
In the study, patients' brains were injected with a harmless virus, genetically modified to carry a human gene which retards nerve cells that become overactive in Parkinson's patients, interfering with movement control. Doctors noted a significant improvement, and scans confirmed the treatment worked by highlighting brain circuits involved in movement that had recovered. Eleven men and one woman received injections into part of the brain most affected by the disease. The scans later showed that some brain circuits that act abnormally in Parkinson's patients were working healthily again.
The patients showed signs of recovery one month after treatment, and three to six months later showed on average a 30 per cent improvement in their movement. One patient's recovery astounded doctors, after tests showed his movement had improved 65 per cent.
"These scans show that the treatment corrects abnormal activity in the brain, and we would only see those changes if the therapy was working," said Dr David Eidelberg, who led the study at the New York University School of Medicine.
Before scanning the patients' brains, it was unclear if their recovery could be explained by the placebo effect, or by the surgery to enable doctors to inject the gene-based drug. Detailed examination of the scans showed changes in the patients' brains could only be explained by the therapy, Dr Eidelberg said.