An experimental gene therapy seems to show potential to slow the debilitating progression of Huntington’s disease, a European biotech company that developed the new treatment says.
Huntington’s disease is a nerve-destroying disease that runs in families and damages movement, robs memory and alters personality while people are in the prime of their lives. It is almost always lethal within 10 to 20 years of diagnosis, neurologists say.
Now, researchers are excited about the results from one company’s small, preliminary clinical study of a treatment that targets the genetic error that causes the disease.
“I have unbridled optimism,” Ed Wild, principal investigator at University College London’s Huntington’s disease centre who was involved in the trial, in an interview with CBC’s As It Happens.
“This is the best news we have ever had in the Huntington’s community.”
The Netherlands-based company, uniQure, announced preliminary findings Wednesday from an experimental gene therapy, suggesting the therapy, administered during brain surgery, slowed progression of the disease by 75 per cent over three years for patients with the highest dose. The trial was small, with around 30 patients enrolled, and the treatment did not cure them of the disease.
So what does it mean?
It’s a potentially promising development for a condition that has had few of them since the discovery of the faulty gene behind the disease in 1993, but experts say there are still unanswered questions and further work to do.
Slowing the progression of the disease, while not a cure, could improve patients’ quality of life.
“People will be able to stay in work longer, they will be able to function longer, they will be able to maintain their independence,” Dr. Sarah Tabrizi, director of the University College London Huntington’s Disease Centre, who led part of the trial, said during uniQure’s a conference call Wednesday.
But what that slowing of disease progression could mean for people who aren’t perfect candidates for brain surgery to receive the potential treatment is unclear. That includes whether people with earlier or later stage Huntington’s could qualify.
The full data has not been made public or peer reviewed by experts independent of the company. Those processes can help identify flaws in the experimental design or shed light on important factors like the best dose or timing.
In a media release, the company said its top-line results demonstrated “a statistically significant slowing of disease progression.”
Dr. Jonathan Kimmelman, a professor of bioethics at McGill University in Montreal, said it is hard to interpret and assess the true impact of the company’s announcement, given the lack of publicly available data.
“It could be very exciting. It also could be like many other press releases, that is, it could be a very exuberant and selective representation of what they have observed.”
Kimmelman also said the information available suggests the treatment appears to slow the disease, rather than cure it or stop it from worsening altogether.
Others are more optimistic.
Rachel Harding, assistant professor at the Leslie Dan Faculty of Pharmacy at the University of Toronto and an editor in chief at HDbuzz, a website focused on Huntington’s disease information, said it’s a good feeling to finally see “something that looks hopeful in clinical trials.”
Harding, however, also recognized the limitations, like the trial’s small sample size — only 12 patients were followed for 36 months at the highest dose — and the lack of long-term data.
“Will the effects of the drug wane or drop off or, you know, will it not work as well as people’s disease progresses?” Harding said. “We don’t know.”
Surgery and treatment considerations
The brain surgery takes at least 12 hours, Wild said, and the gene therapy needs to be delivered to two regions of the brain during real-time MRI scanning.
The treatment aims to correct the mutant Huntingtin gene. Surgeons use a modified virus to deliver the potential gene therapy treatment, called AMT-130.
The potential treatment aims to lower levels of mutant huntingtin protein that disrupt normal function of neurons in the brain. Previous single-dose gene therapies cost $2 million.
The company said it has a meeting with the U.S. Food and Drug Administration later this year to share the data with the agency, ahead of its planned 2026 submission to the FDA for marketing approval.
