Hopes are being raised for a new "on demand" epilepsy pill which can be taken when people feel a seizure coming on.
The pill has been developed by a team at University College London, UK, led by Professor Dimitri Kullmann. They explain that about 50 million people worldwide, including 600,000 in the UK, suffer from epilepsy. About a quarter are resistant to normal treatments, drugs that suppress the excitability of all brain cells and cause side-effects.
But the new pill may help this group, as it genetically modifies brain cells, making them sensitive to a compound which is normally inactive. Professor Kullmann describes the process. "First, we inject a modified virus into the area of the brain where seizures arise," he says. "This virus instructs the brain cells to make a protein that is activated by clozapine-N-oxide, or CNO, a compound that can be taken as a pill. The activated protein then suppresses the over-excitable brain cells that trigger seizures, but only in the presence of CNO."
He adds: "If we can take our new method into the clinic, which we hope to do within the next decade, we could treat patients who are susceptible to severe seizures with a one-off injection of the modified virus, and then use CNO only when needed."
Full details of the treatment are described in yesterday’s (27 May) issue of Nature Communications. The pill could also be taken as a preventative measure, they believe, in situations when seizure risk is high, such as when people are ill, sleep deprived, or at certain times of the menstrual cycle.
The team say it combines genetic and chemical approaches to suppress seizures without disrupting normal brain function. They tested it on rodents and are planning future trials on human volunteers.
Katzel, L. I. et al. Chemical-genetic attenuation of focal neocortical seizures. Nature Communications 27 May 2014; doi: 10.1038/NCOMMS4847
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