Gene therapy for Parkinson’s

AFP, October 15, 2009

A gene therapy for Parkinson’s disease that has been tested on lab monkeys is showing good early results in a small-scale trial on humans, French researchers say.

The therapy entails taking three genes that produce dopamine, a vital neurochemical that is depleted in Parkinson’s. The genes are then inserted into a disabled equine virus that is then injected into the brain.

Six human volunteers began clinical trials a year ago, and the results are “extremely encouraging”, as measured in control of Parkinson’s symptoms and in side effects such as brain inflammation, neurosurgeon Stephane Palfi said.

Another half-dozen volunteers will be recruited for the trial, said Jarraya, of the Henri Mondor Hospital in Paris.

If all goes well, a so-called Phase III trial, involving a large number of patients to assess the treatment for safety and effectiveness, will start in 2013.

The tentative trials on humans were authorised after three-and-a-half years of experiments on macaque monkeys that had been given neurotoxins to replicate Parkinson’s.

The monkey experiments are reported on Wednesday in the US journal Science Translational Medicine.

The gene therapy, called ProSavin, restored the monkeys’ dopamine levels, corrected motor problems and prevented dyskinesias, the term for jerkiness, rigidity and tremor.

There was “80 per cent recovery” among the animals, “and the results were stable for up to 44 years after treatment”, said Bechir Jerraya another neurosurgeon involved in the trial.

Parkinson’s is characterised by the loss of cells that produce dopamine, a critically important neurotransmitter that ferries chemical messages within the brain.

In about one-third of cases, it also results in dementia. Parkinson’s affects at least one per cent of people over the age of 65.

Well-known people with Parkinson’s include the late pontiff John Paul II and film actor Michael Fox.