The First Real Triumph for Gene Therapy – Parkinson’s

Phase I clinical trials are intended to define the general safety profile of an experimental drug, to enable a dose schedule to be worked out for Phase II efficacy trials. Any indication of effectiveness from a Phase I study is a bonus. According to a report in the medical journal Lancet, the first study to use gene therapy to treat any neurodegenerative disorder – in this case, Parkinson’s disease – showed no toxic effects and 25% to 30% improvement in a specific rating scale after 1 year.

Twelve patients (11 women) with advanced Parkinson’s had the glutamic acid decarboxylase gene delivered directly into the cells of the subthalamic nucleus of the brain. Four patients each received a low, medium or high dose or the preparation. The gene was carried by a harmless adeno-associated virus; it produces gamma-aminobutyric acid (GABA), an inhibitory neurotransmitter that quiets excessive neuron firing. The injection was done on one side, and the major improvements were seen in the opposite side of the body.

This is indeed a ‘breakthrough’. But the authors believe it carries implications for gene therapy beyond Parkinson’s disease, into a whole realm of neurodegenerative conditions, such as Alzheimer’s, Huntingdon’s, and Lou Gehrig’s disease.