Human trials of Huntington’s drug offers hope for new gene-silencing treatments
The first human trial examining the safety of a drug designed to reduce the levels of a corrupted protein that is responsible for the devastating effects of Huntington's disease has proven a success. These early, yet exciting results, suggest potential for a new drug that could possibly be adapted to treat other brain disorders such as Alzheimer's and Parkinson's.
Huntington's disease is a devastating neurodegenerative condition caused by a mutation in a gene called huntingtin, which produces a protein of the same name. When this mutation is present the huntingtin protein is corrupted and subsequently damages brain cells, resulting in the disease's progressively irreversible effects on motor and cognitive skills.
The new drug, called IONIS-HTTRx, works by intercepting the mRNA signals sent out by the mutated gene. This effectively blocks the production of the corrupted protein to either slow the progression of Huntingon's, or prevent it from taking hold in the first place.
After over a decade in development, and following successful animal trials, this first phase of human trials is showing exciting promise for this new treatment. The first phase of any human trial is always designed to primarily demonstrate safety not efficacy and in this instance the researchers are reporting the drug was well-tolerated and should now progress to the next phase of testing.
The efficacy on the other hand, which was not a primary goal of this first trial, has been noted by the researchers as excitingly positive. They report that after treatment with the drug there was a significant reduction in the presence of the mutated protein measured in the spinal fluid of the subjects.
"The results of this trial are of ground-breaking importance for Huntington's disease patients and families," says Sarah Tabrizi, lead researcher on the trial at University College London. "For the first time a drug has lowered the level of the toxic disease-causing protein in the nervous system, and the drug was safe and well-tolerated. The key now is to move quickly to a larger trial to test whether the drug slows disease progression."
Further trials will examine how effective this drug is at tangibly reducing the symptoms of Huntington's, but earlier animal studies have suggested positive future results.
Perhaps the most exciting outcome of this research is the new drug's potential applications for other neurodegenerative diseases. Dysfunctional proteins have been linked to diseases such as Alzheimer's and Parkinson's and this new drug offers proof of a process that can effectively target, and reduce production of, those proteins.
Ed Wild, a researcher at UCL's Huntington's Disease Centre suggests this drug can indeed be adapted to target other proteins, and in an interview with CNN he adds, "This is proof of principle you can inject these drugs into spinal fluid; they get into the brain and reduce harmful proteins."
It's certainly early stages in the human trial process, but this kind of gene-silencing approach could prove revolutionary for the treatment of a number of diseases.
The full results of the trial are currently unpublished but should be released in a peer-reviewed journal sometime in 2018.
Source: University College London