An experimental new gene therapy is showing promising results in an early trial of three adults with drug-resistant epilepsy, showing a 92.6% reduction in seizures.
Published in the New England Journal of Medicine, the research by Beijing neurosurgeon Yang Dai and colleagues explores the use of a modified virus which targets specific cells in the brain where seizures start.
Surgeons delivered the virus directly into the affected area of the brain, and the virus then inserts a gene in those cells, allowing neighbouring cells to bind with the medication clozapine.
Combining gene therapy with a drug is known as chemogenetics. This type of gene therapy allows the treatment to be precise and for the treatment levels to be adjustable, which isn’t the case with other forms of gene therapy.
The three adults who trialled this therapy have hippocampal sclerosis causing drug-resistant epilepsy which they’d had between 10 and 25 years.
For two participants, their seizures dropped from nine to one in the space of two months, and the third participant’s seizures fell from four to zero per month.
Cautions and study limitations
While neurologist from University College London, Matthew Walker, called the experiment “exciting” for its dramatic effect and few side effects, he cautions that there are limitations.
The study is small and there are no controls used, as its focus was on the safety of the treatment. Dr Walker added that it’s not clear from this study whether it’s the combination of treatments that’s effective or just one.
Another concern shared by Dr Walker was that high doses of clozapine could be linked to heart problems and other complications. He said he is hopeful that in the future there will be “better drugs” for therapy like this.
Future research is focusing on larger trials of this treatment as well as monitoring the three participants in the long term.
Gene therapy and precision treatment
Targeted and personalised treatment, such as gene therapy, was identified by the UK Epilepsy Priority Setting Partnership as one of its top 10 research priorities in 2022. This was done in collaboration with health professionals, people with epilepsy and their families.
Earlier this year, a baby in Australia also became the first to receive precision treatment for KCNT1, a form of epilepsy caused by a mutation in the KCNT1 gene.
Eight-month-old Bhodi Higginson’s specialists said it was both “exciting” and “scary” to administer this treatment, but his seizures stopped just days after he received it.
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