Cannabidiol shown to be effective for a severe form of Epilepsy
The first ever Class 1 clinical trial of the drug cannabidiol has shown it is effective at reducing convulsive seizures
in a severe type of epilepsy in children. The Dravet syndrome is a severe childhood epilepsy disorder associated with
drug-resistant seizures, developmental delay, and a high mortality rate.
The results of this study have just been published in a paper in the New England Journal of Medicine.
The only New Zealander on the project, Associate Professor Lynette Sadleir is an epilepsy researcher and paediatric
neurologist at the University of Otago, Wellington.
“This study is significant because it is the first scientific clinical evidence we have of an effect of a plant-derived
cannabinoid therapeutic medication on epilepsy. Previous reports of effects, widely reported in the media, were of
individual children and it was unclear if these reflected a true effect for children in general with this type of
epilepsy,” she says.
Associate Professor Sadleir’s expertise is in diagnosing children with specific types of epilepsy. She was part of an
international team (Cannabidiol in Dravet Syndrome Study Group) whose role was to confirm for the trial that the
children included in the study did indeed have Dravet Syndrome.
“Seizures are difficult to control in the Dravet Syndrome. It is a rare genetic form of epilepsy that we have been doing
a lot of research on. This syndrome is a result primarily of loss-of-function of a sodium channel in the brain caused by
mutations of a specific gene, called SCN1A,” says Associate Professor Sadleir.
For this multinational double-blind, placebo-controlled trial, 120 children and young adults with the Dravet syndrome
and drug-resistant seizures received either cannabidiol oral solution or placebo, in addition to standard anti-epileptic
treatment. The primary end point was the change in convulsive-seizure frequency over a 14-week treatment period, as
compared with a four-week baseline period.
“We found that convulsive seizures in children on the cannabidiol decreased from 12 to six seizures per week, while
those children taking placebo only decreased from 15 to 14 seizures per week. In addition, five per cent of children
became seizure free on cannabidiol, while no child became seizure free on placebo.”
“The children taking cannabidiol did however have more reported side effects than those on placebo, including diarrhoea,
vomiting, fatigue, fever, sleepiness and abnormal liver function,” says Associate Professor Sadleir.
“These were so significant that thirteen per cent of the children taking cannabidiol withdrew from the study due to side
effects.”
“It is important to remember that the medication used in this trial was a 97 per cent pure cannabidiol pharmaceutical
grade medication and the results cannot be extrapolated to non-pharmaceutical grade products. Also, this was a brief
trial lasting only three months so we do not know what the long term effects of this medication on a child’s developing
brain might be.
“More research is needed but this trial is a positive beginning to our understanding of how cannabidiol may help
children with this severe epilepsy.”
ends