Orrin Devinsky, a researcher at the New York School of Medicine, told Medscape: “There have been very promising results in animal studies … and patients are reporting dramatic benefits with these [drugs] in reducing epileptic seizures, but there is no controlled data.”
He added that placebo effects are more common in therapies for paediatric epilepsy because parents are so willing to see an improvement in their children.
Dr Devinsky is currently working on the US’s first Food and Drug Administration (FDA)-approved study into the efficacy of cannabidiol – one of the cannabis plant’s principal chemical compounds – as an antiepileptic drug.
Cannabidiol has already been granted orphan drug status by the FDA for children with Dravet syndrome, a rare and severe form of paediatric epilepsy that does not respond to conventional therapies. Should the study have a positive outcome, it may become more widely available.
A drug containing 50 per cent cannabidiol and 50 per cent delta-9 tetrahydrocannabinol – also known as THC, cannabis’ psychoactive ingredient – is already marketed in the UK, Canada, New Zealand and several European countries as Sativex, which is prescribed for multiple sclerosis.
However, only pure cannabidiol will figure in the FDA-approved study, largely because THC – in addition to being psychoactive – has been associated with mental disorders and permanent damage to short-term memory in children.
“If you are considering using products containing THC, the benefits would have to outweigh the risks. If a child was having 100 seizures a day, then its use might be justified, but it would not be warranted for milder epilepsy,” commented Dr Devinsky.
The study is set to begin in January. It will take place at five 25-patient sites and most subjects will be children with Dravet syndrome, though some young adults and children with other forms of epilepsy will also participate.