A “groundbreaking” new therapy could slow or even prevent Huntington’s disease, one of the most devastating degenerative brain conditions.
Furthermore, the science behind the new gene therapy could potentially be adapted to treat similar ‘dementia’ conditions which gradually erode and kill brain cells.
Huntington’s puts patients in a gradual and irreversible decline, affecting their movement, memory, ability to think clearly and their behaviour and personality. It generally affects people in their 20s and 30s, striking at the prime of life, and patients tend to survive for 10 to 20 years after the symptoms first appear.
Around 8,500 people in the UK currently have Huntington’s and a further 25,000 will develop it in later life. The vast majority of those know it is coming, as Huntington’s is also inherited, meaning it can devastate generations of the same family.
Perhaps worst of all, those who know they are likely to develop Huntington’s (because they carry the defective gene) also know there is nothing they can do about it. Until now there has been no effective therapy to treat the disease.
But now a research team at University College London say there is fresh hope for those facing Huntington’s after a new trial therapy showed remarkable results in 46 volunteers. It is not a cure for the disease, but it could slow or even halt its development in those with the faulty gene. Experts who have analysed the trial believe it could be the biggest breakthrough in treating neurodegenerative conditions in the past 50 years.
Huntington’s is caused by a genetic error in a section of DNA. That section contains the instructions for making a protein (called huntingtin) which is vital for brain development. But in people with the genetic error, those instructions become confused, resulting in a corrupted protein which instead kills brain cells.
The new treatment cannot remove or correct the defective gene, but it does stop it transmitting the faulty instructions and thereby creating the damaged proteins which kill brain cells. In other words, it ‘silences’ the faulty gene.
The drug is injected into the spinal fluid of patients and researchers knew that procedure carried a risk for the first volunteers, as it was impossible to know for sure how they would react. It could even have caused fatal meningitis. Thankfully, the first trial showed that the drug was not only safe but well tolerated by patients. Most crucially of all, it significantly reduced the levels of the corrupted and damaging huntingtin protein in the brain.
Lead researcher Professor Sarah Tabrizi said: “For the first time we have the potential, we have the hope, of a therapy that may one day slow or prevent Huntington’s disease. This is of groundbreaking importance for patients and their families.”
It could be several years before the new treatment is fully tested, developed and widely available, but for people with Huntington’s it brings the hope of a future, not only for them, but for their children who have inherited the faulty gene. Research is also beginning to determine whether the same approach could be applied to other types of dementia caused by a build-up of toxic proteins in the brain, such as Parkinson’s disease.
Researchers and drugs companies which develop new treatments are notoriously cautious about not overplaying the results of early trials, but the pharmaceutical company which helped develop the new Huntington’s treatment admitted the trial results had “substantially exceeded” its expectations. Full details of the trial will be published next year.