The results of a recent clinical trial testing a new way of delivering the nerve growth factor, GDNF, into the brains of people with Parkinson’s demonstrate that it is safe and well tolerated.
Glial cell-line derived neurotrophic factor, or GDNF as it is more commonly known, is a protein that supports and nurtures brain cells and is naturally found in the brain. Laboratory studies have suggested that GDNF demonstrates neuroprotective properties, that it might help brain cells affected by Parkinson’s recover or regenerate. Currently, there is not a treatment that can do this.
GDNF is a large protein that can’t reach the brain from the bloodstream which means it needs to be delivered directly to the brain, and this has until now been done by surgical infusion. Cure Parkinson’s has championed GDNF for a number of years, supporting a pioneering phase 2 GDNF clinical study in Bristol in 2012. We are encouraged to see the results of this latest phase 1 clinical trial of GDNF.
This recent trial involves a type of gene therapy, where a new gene is delivered into brain cells, replacing non-functioning genes; here the new gene provides the instructions for making a functioning protein at sufficient levels to be a potential treatment.
Scientists at Ohio State University and the biotech company Asklepios BioPharmaceutical have used carefully engineered viruses that act as biological delivery vessels to ‘infect’ brain cells with their genetic contents – in this case the gene needed to make GDNF. This pioneering delivery approach removes the need for invasive surgical infusion treatment.
In the small phase 1 clinical trial, the researchers found this treatment to be safe and well tolerated up to 5 years afterwards. The researchers have a second phase 1 study currently ongoing which will finish later this year with a longer term follow up period continuing on until 2026.
Both studies have been small (12 participants in each) and ‘open label’ meaning all participants are aware they are receiving GDNF treatment. We now look forward to a much larger, ‘blinded’ study assessing the efficacy of GDNF gene therapy in Parkinson’s in the not too distant future.
