Gene therapy hope for Parkinson's disease

US researchers have reported encouraging initial results from a trial of a new type of gene therapy treatment for Parkinson's disease (PD). The Phase 1 clinical trial, designed to test the safety and effectiveness of the approach, involved 12 patients with advanced PD. After a year, most had seen some improvement in their condition, while none had suffered serious effects. The team, from biopharmaceutical company Ceregene, presented the findings at the annual meeting of the American Association of Neurological Surgeons, held in Washington last week.

People with PD are affected by tremors, stiff muscles and slow movements, caused by a gradual loss of dopamine-producing cells in an area of the brain controlling movement. Existing treatments for Parkinson's disease involve replacing the dopamine, a chemical that controls brain activity. In the Ceregene trial, the researchers used a gene that makes a protein called neurturin - a 'growth factor' that can repair damaged and dying brain cells. The scientists packaged up the therapeutic gene in a harmless virus, and delivered it directly to the part of the patients' brains affected by the disease, via holes drilled into their skulls.

Two different doses of new treatment, called 'CERE-120', were used in the trial. Patients who received the higher dose showed a 36 per cent improvement in their symptoms about six months after the procedure, while those who received a four-fold lower dose had improved by nine months. 'We are pleased with the results of this early study which suggests that the majority of patients treated with CERE-120 may have exhibited significant and stable improvement after receiving a single administration of CERE-120', said Jeffrey Ostrove, president and chief executive of Ceregene.

The team are now recruiting 51 further PD patients from nine US medical centres to take part in a Phase 2 trial. Two thirds of the participants will received the gene therapy treatment, while the remaining third will form the untreated control group. The company is also developing gene therapy treatments for the Alzheimer's disease and amyotrophic lateral sclerosis (ALS), two other neurodegenerative disorders. The Phase 2 Parkinson's trial is being partially funded by the Michael J Fox Foundation for Parkinson's Research. Actor Michael J Fox set up the Foundation in 2000, nine years after he was diagnosed with the early onset form of the disease.