Recently, biotech company Ceregene announced evidence of increased levels of the trophic factor neurturin in the brain, for four-plus years following CERE-120 gene therapy to treat Parkinson’s disease (PD).

In PD, gene therapy approaches aim to limit the loss of dopamine neurons in the brain by introducing the gene that makes the trophic factor neurturin, a protein that promotes the survival, growth and function of neurons. Ceregene’s therapy, called CERE-120, works by increasing levels of neurturin in targeted sites in the brain most affected in PD.

Ceregene’s announcement suggests this process may have been at work in two now-deceased participants who were part of early human studies on CERE-120. Autopsies show that four years following gene therapy, certain parts of their brains contained increased levels of neurturin and healthy dopamine cells.

Previous analysis from the same study, taken just months after administration of CERE-120, showed that, while neurturin was elevated in the area of the brain where it was first delivered, little of the protein made its way to the part of the brain where it was hoped to activate genes to repair the dying neurons.

The new data could support the idea that brain changes resulting from gene therapy require time to develop.  But there is much more work to do: This study focused on better understanding what’s happening in the brain in response to gene therapy.  It did not address long-term clinical benefit.

MJFF is currently funding Ceregene to do just this: Researchers are aiming to find out if neurturin can repair damaged dopamine neurons and protect them from further injury in a clinical setting, improving symptoms and possibly stopping the progression of the disease in its tracks. Clinical results are expected in 2013.