James GallagherHealth and Science Correspondent
BBC/Fergus Walsh
Professors Ed Wild and Sarah Tabrizi lead the trial section in the UK
Doctors say one of Huntington's most dangerous and devastating diseases – Huntington's disease is successfully treated for the first time.
The disease runs through the family, ruthlessly killing brain cells, similar to the combination of dementia, Parkinson's disease and motor neuron disease.
The emotional research team became weeping when they described the data showing how the disease slowed down 75% of patients.
This means that the decline you expect will usually take four years after treatment, which will allow the patient to have decades of “quality life”.
The new therapy is a gene therapy given during 12 to 18 hours of delicate brain surgery.
The first symptom of Huntington's disease often occurs in your 30s or 40s, and is usually fatal within twenty years – opening up the possibility that early treatment can prevent symptoms from appearing.
Professor Tabrizi, Director of the Huntington Center for Diseases at University College London, described the results as “spectacular”.
“We never thought of expecting a 75% slowdown in clinical progress,” she said.
There was no treatment patient, but one patient has been retired by medical treatment and has returned to work. Others at the trial are still walking, although wheelchairs are expected to be needed.
Treatment can be very expensive. But it is a real moment of hope, the disease hits their peak moments and destroys families.
BBC/Fergus Walsh
Jack May-Davis has genes that cause Huntington's disease
Huntington runs through Jack May-Davis' family. His father Fred and his grandmother Joyce also had the wrong genes that caused the disease.
Jack said watching his father's inability to stop decline was “really bad and terrible”.
The first symptoms occurred in Fred's late 1930s, including changes in behavior and how he moved. He ended up requiring palliative care 24/7, and then he died in 2016 at the age of 54.
Jack, 30, is a barrister clerk who is newly engaged to Chloe and has been involved in UCL research, turning his diagnosis into a positive one.
But he always knew that he was destined to share his father's fate until today.
Now he said the “absolutely incredible” breakthrough left him “overwhelmed” and was able to show “a brighter future that really allowed me to think my life might be longer.”
May-Davis Family
A young Jack and his father Fred died of Huntington's disease.
Huntington's disease is caused by mistakes in our DNA, called the Huntington gene.
If one of your parents has Huntington's disease, you have a 50% chance of inheriting the altered gene and eventually developing Huntington's genes.
This mutation turns the normal protein needed in the brain, called Huntington protein, into a killer of neurons.
The purpose of treatment is to permanently reduce the levels of this toxic protein in a single dose.
The therapy uses cutting-edge genetic medicine that combines gene therapy and gene silencing techniques.
It starts with a changed safe virus to contain specially designed DNA sequences.
It was penetrated deep into the brain using a real-time MRI scan to guide the microcatheter to two brain regions – the caudate nucleus and the shell. This takes 12 to 18 hours of neurosurgery.
The virus then works like a microscope postman – delivering new DNA in brain cells, which plays active in that cell.
This turns neurons into a factory to avoid their own death for treatment.
These cells produce a small fragment of genetic material (called microRNA) designed to intercept and disable instructions sent from the cell's DNA (called Messenger RNA) to construct the mutant Huntingtin.
This can lead to lower levels of mutated Huntington in the brain.
UCLH
Two brain scans were scanned side by side. The one on the left is healthy, and the one on the right shows brain material loss when neurons die in Huntington's disease.
The results of the trial, involving 29 patients, have been released in a statement from the company Unique, but have not been fully released for review by other experts.
The data show that after three years of surgery, the average slowdown of the disease was 75% based on measures combining cognitive, motor function and daily life management capabilities.
The data also suggest that treatment is saving brain cells. If the disease continues to progress, the levels of nerve filaments in the spinal fluid should increase by one third, but are actually lower than at the beginning of the trial.
“This is the result we've been waiting for,” said Professor Ed Wild, a neurologist at the National Hospital of Neurology and Neurosurgery at UCLH.
“We will never see such a result, so living in a world where we know it is possible, and the actual magnitude of the actual effect is breathtaking and it’s hard to completely encapsulate emotions.”
He said he had “some tears” about the impact it might have on the family.
The treatment is considered safe, although some patients do cause headaches and confusion due to the virus and develop inflammation, which either resolves or requires steroid treatment.
Professor Wild expects that this therapy “should last for life” because brain cells will not be replaced in the same way as blood, bones and skin.
In the UK, the US and Europe, about 75,000 people suffer from Huntington's disease, and thousands of mutations mean they will develop the disease.
Unique said it will apply for a license in the U.S. in the first quarter of 2026 with the goal of launching the drug later that year. Dialogue with British and European authorities will begin next year, but the initial focus will be on the United States.
Dr. Walid Abi-Saab, Unique’s chief medical officer, said he was “incredibly excited about what the outcome means for the family”, adding that the treatment has the potential to “fundamentally change” Huntington’s disease.
However, due to the highly complex surgery and expected costs, the drug will not be available to everyone.
Professor Wilderness said: “It will definitely be expensive.”
There is no official price for this drug. Gene therapies are often expensive, but their long-term effects mean they are still affordable. In the UK, the NHS did pay £2.6 million for each patient gene therapy.
Professor Tabrizi said this gene therapy “is the beginning” and will open the door to treatments that can attract more people.
She paid tribute to the “really brave” volunteers who attended the trial, saying she was “happy for the patients and the family.”
She has worked with a group of young people who know they have the gene but have not yet had symptoms, called Zero Huntington's symptoms, with the goal of conducting the first preventive trial to see if the disease can be delayed significantly or even stopped completely.