12th December 2017
Major breakthrough in Huntington's disease
University College London reports that a genetic error responsible for Huntington's disease has been corrected in patients for the first time.
In a milestone for medical research, the first drug targeting the cause of Huntington's disease has been shown to be safe, well-tolerated and successful at reducing the harmful huntingtin protein in the nervous system.
After more than a decade in pre-clinical development, the first human trial of the drug, IONIS-HTTRx, began in late 2015, led by Professor Sarah Tabrizi from University College London's (UCL) Institute of Neurology and sponsored by Ionis Pharmaceuticals. The trial enrolled 46 patients with early-stage Huntington's at nine study centres in the UK, Germany and Canada. Each patient received four doses of either IONIS-HTTRx or a placebo, given by injection into the spinal fluid to enable it to reach the brain. As the phase 1/2a trial progressed, the dose was increased several times. Patient safety was monitored throughout the study by an independent committee.
This week, after completion of the trial, it has been confirmed that the drug was both safe and effective in the human participants and it is recommended that further testing now goes ahead. Described by one expert as possibly the biggest breakthrough in neurodegenerative diseases for the last 50 years, this new drug could offer real hope to the hundreds of thousands of people affected by the condition worldwide.
Huntington's has been recognised as a disorder since at least the Middle Ages. It was first described in 1841 by Charles Oscar Waters and studied in much more detail in 1872 by George Huntington, after whom it is named. A genetically inherited disorder, it results in the death of brain cells, initially causing subtle problems with mood or mental abilities, then progressing to a general lack of coordination and jerky body movements. Physical abilities gradually worsen until the person is unable to talk, while their mental abilities decline into dementia. Death typically occurs 15-20 years after detection of symptoms, with suicide reported in about 9% of cases. Symptoms usually begin between 30 and 50 years of age, but can start at any age.
"The results of this trial are of ground-breaking importance for Huntington's disease patients and families," said Professor Tabrizi. "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."
"This is a potential game-changer – not only for Huntington's disease patients but also for genomic medicine in general," said Dr Philippa Brice, from the PHG Foundation think tank. "Though more work needs to be done, if gene silencing lives up to this promise we could be on the brink of some of the personalised treatments that patients with severe genetic diseases need so badly."
"I really think this is, potentially, the biggest breakthrough in neurodegenerative disease in the past 50 years," said Professor John Hardy from the UCL Institute of Neurology, who was not involved in this research, but won the $3m Breakthrough Prize in Life Sciences in 2015. "That sounds like hyperbole – but that's how I feel at the moment."
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