Huntington’s, a fatal condition, is caused by a toxic protein made in the brain. It affects sufferers’ ability to move and think, and alters their behaviour. Patients know they will die from it and, as it is a genetic condition, there is a 50 % chance their children will be affected. Now doctors at the University College London believe their new, experimental drug lowers the level of the protein and should stop brain cells dying.
Speaking to the BBC, Peter Allen, 51, who took part in the study said, ‘You end up in almost a vegetative state, it’s a horrible end.’ Because it is genetic, patients have usually seen family members succumb. In Peter’s case, his mother, uncle and grandmother all died from Huntington’s. Tests show his brother and sister will both go on to develop the condition.
Until now there has been no treatment available to slow down or halt the disease, which is caused by an error in a section of DNA, called the huntingtin gene. The gene contains the instruction to produce huntingten, vital for brain development. But in those affected, a genetic error corrupts the protein, turning it into a killer of brain cells.
Professor Sarah Tabrizi led the trial at UCL’s Huntington’s Disease Centre and has spent the last 21 years working with patients suffering from the disease. Interviewed on BBC Radio 4’s PM programme she said, ‘It’s a devastating disease, Over that time many of my patients have died and it makes me passionate about (…) trying to find treatments for this disease.’
She explained that, for the first time, a piece of DNA has been chemically modified to bind to the Huntington’s disease ‘message’ made by the disease’s gene, causing it to be broken down. That results in less of the toxic, mutant huntingten protein being produced, and so limiting the damage.
‘The trial that we were running was testing whether infusing this drug into the spinal fluid of patients with the disease was safe and well-tolerated and, importantly, did we manage to lower the levels of the toxic, mutant Huntington’s disease protein? And all of those were achieved.’
She described the results as an enormous step forward in the development of molecular therapies targeting the root cause of the disease. Now the team is intending to test the drug in hundreds of patients over a longer period to see if it slows the disease progression. If that is successful, they then want to treat people who carry the disease gene but are completely well, prior to when they become symptomatic.
‘One day we want to be able to be in a position to prevent the disease occurring. It is the beginning of taking a particular molecular therapy forward.’
‘For the first time, a reason to go on’
Charles Sabine, a spokesperson for Huntington’s disease lay associations around the world and himself a sufferer, told PM that he is a carrier and has seen family members dying of Huntington’s, ‘It’s a particularly horrible disease because (…) its genetic nature means that people see their own future.’ He explains that once you know about the existence of the gene, it dominates everything, as every possible symptom could be the beginning of the decline.
‘Scientists like Sarah have to be equivocal (…) but what I can tell you is that this news today (…) is a genuine step forward for a disease which has never had a single therapy at all (…). Nothing you can do about it. So what this does is something absolute, it gives people in my position the reason to go on, which they have not had before.
‘This now completely changes the playing field. This now means that people have a reason to wait to see what happens next year and the year after that. It is an extraordinary moment.’