In what is thought to be one of the biggest breakthroughs in the treatment of neurodegenerative diseases in the last 50 years, researchers have created a drug that may one day slow the progression of Huntington's disease.
A tragic neurodegenerative disease, Huntington's is caused in most people by a single genetic mutation, although a small number of others do develop the genetic fault through random mutation. The gene in question codes for a protein known as huntingtin that builds up in the brain, causing the progressive degeneration of the nervous system and significantly harming movement, learning, thinking, and emotions.
The new drug is designed to disrupt the expression of this faulty gene, preventing the production of huntingtin and thus hopefully slowing the onset of the disease.
Known as IONIS-HTTRx, the drug does not target the gene itself, but is instead a piece of synthesized genetic code that binds to the piece of messenger RNA that transports the information needed to build huntingtin around the cell. By doing this, the drug destroys the messenger molecule before the damaged proteins form. The researchers were able to dramatically cut the levels of this protein found in the brain.
It is important to stress that the trials carried out so far were not looking at whether or not the new treatment prevented the symptoms of the disease from progressing, so the researchers cannot say unequivocally that it works. Instead, they were looking at the level of the toxic protein found in the nervous system.
They found that the level of the toxic protein in the brain was linked to the dose of the medicine, suggesting that the new drug does indeed target the manufacturing of the protein as expected. This is coupled with the fact that the drug had no adverse effects and was seemingly safe.
“The results of this trial are of ground-breaking importance for Huntington’s disease patients and families,” explains University College London's Professor Sarah Tabrizi, who led the research, in a statement. “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.”
The trials began in late 2015, when 46 patients with early Huntington’s disease started their treatment with the experimental drug. The procedure at the moment is unfortunately pretty invasive, requiring injections directly into the spinal fluid itself.
Trials are expected to start looking at whether the drug does slow the onset soon, and expectations are high. There is also hope that the methodology can be applied to other neurodegenerative diseases, such as Alzhiemer's and Parkinson's.