In 2013, a biotech company called Ceregene reported disappointing results from their experimental gene therapy clinical trial for Parkinson’s. The data from the study suggested that the therapy had no clinical effect on the progression of Parkinson’s (Click here to read the press release).
Today, however, researchers associated with that biotech company have published a new report that suggests that the treatment had beneficial effects in the brain, but not enough of it was delivered.
The treatment was a gene therapy approach (which involves using DNA rather than drugs to treat medical conditions), and it involved a protein called neurturin.
In today’s post, we will discuss what neurturin is, we will review what this new study found, and consider what the implications could be for future gene therapy trials in Parkinson’s.
Reanalysing clinical trial data (called post-hoc analysis) provides a very useful way of generating new hypotheses even if the initial study did not reach its primary endpoint (that is to say the study did not demonstrate a successful outcome. Post-hoc analysis must be handled carefully, as the findings of such investigations can be viewed as selective ‘cherry picking’ of interesting outcomes. They will need to be tested to determine if they are real effects.
Even more important than post-hoc analysis, however, is following up participants who took part in a trial to see if there were any long-term benefits from the treatment. I often wonder how much important data is lost after a clinical trial simply becomes there is no long term follow up and study investigators lose track of participants as they drift away.
Precious nuggets of information can be gained from long-term analysis. And this week we saw a really interesting example of this.
Here is the research report:
Title: Long-term post-mortem studies following neurturin gene therapy in patients with advanced Parkinson’s disease.
Authors: Chu Y, Bartus RT, Manfredsson FP, Olanow CW, Kordower JH.
Journal: Brain. 2020 Mar 1;143(3):960-975.
PMID: 32203581 (This report is OPEN ACCESS if you wouldl like to read it)
In this study, the researchers were looking at postmortem brain sections from 2 participants who took part in a clinical trial investigating a treatment called neurturin.
What is neurturin?