A human trial shows that synthetic strands of DNA meant to "silence" a problematic gene can slow down the production of a protein that leads to irreversible damage in the brain.

Huntington’s disease is caused by a mutation in the HTT gene that causes the body to create a rogue version of a protein called huntingtin; this altered protein damages parts of the brain. The new drug, called Ionis-HTTRx, is a small piece of synthetic DNA that blocks the production of that protein by silencing the HTT gene. The drug has to be injected into the fluid around the spine using a large needle.

Now the company behind the drug, Ionis Pharmaceuticals, reports that a phase 1 trial of 46 patients has shown that the drug successfully lowers the level of the toxic protein in the nervous system. And the results have caught the eye of Big Pharma: Roche has announced that it’s licensing the drug from Ionis for $45 million and will take on its development going forward.

Sarah Tabrizi, a professor of clinical neurology at University College London who ran the clinical trial, said in a statement that the results are of “ground-breaking importance for Huntington’s disease patients and families.” Now Roche will carry out further trials to investigate whether the reduced protein levels have a meaningful impact on the progression of the disease itself.

This isn’t the first time that so-called gene silencing drugs have been shown to be successful (see “How a Boy’s Lazarus-like Revival Points to a New Generation of Drugs” and “Gene-Silencing Drugs Finally Show Promise”). But it is the first drug to target the underlying cause of Huntington’s.

According to the Guardian, some researchers hope that the same technique could be modified and applied to other incurable brain diseases, like Alzheimer’s and Parkinson’s.