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29 June 2016

Cannabis-based drug shows promise in severe epilepsy

Latest trial into the use of a cannabis-based drug for the treatment of a highly drug-resistant form of epilepsy has shown positive results.

Earlier this year, Epidiolex, a liquid formulation of the pure plant-derived cannabidiol showed positive results in the treatment of people with Dravet syndrome. Now a separate trial has shown a significant reduction in frequency of drop seizures in those with Lennox Gastaut syndrome.

Both are severe childhood syndromes with a tendency to multiple seizures on a daily basis. Both are refractory to conventional drug therapies.

Trial details

The recent trial involved 171 people with Lennox Gastaut syndrome. The average age of participants was 15 years and the average number of drop seizures (atonic, tonic and tonic clonic) per month was 74. On average participants were taking around three epilepsy drugs and had tried and not responded to another six different epilepsy drugs previously.

Eighty-six people in the group were given Epidiolex in addition to their routine medication while the other 85 were given a placebo in addition to their drugs.

Over a 14 week period, there was an average reduction in seizure frequency of 44 per cent, compared with 22 per cent in the placebo group.

Epilepsy Society comments

Epilepsy Society's medical director, Professor Ley Sander welcomed the results. He said: ‘The Lennox Gastaut spectrum encompasses some of the most severe and difficult-to-treat childhood epilepsy syndromes. It can involve multiple seizures on a daily basis and is distressing for both the children, their families and carers.

‘The results of this first phase 3 placebo-controlled  trial into the use of medical cannabidiol in treating children with Lennox Gastaut syndrome, offers some hope to families of a potential alternative treatment option.

‘The results demonstrate a significant reduction in seizures alongside acceptable levels of safety. It will be interesting to see the results of the second phase 3 trial of Epidiolex for this very severe epileptic encephalopathy.’


Epidiolex has been developed by GW Pharmaceuticlas from cannabidiol, a non-psychoactive component of the cannabis plant.

Overall, 86 per cent of the Epidiolex group experienced an adverse event compared with 69 per cent on the placebo. The most common adverse events (occurring in more than 10 percent of Epidiolex-treated patients) were: diarrhoea, somnolence, decreased appetite, pyrexia (fever), and vomiting. 

Of those on Epidiolex who reported an adverse event, 78 per cent reported it to be mild or moderate. Twenty people on Epidiolex experienced a serious adverse event (nine of which were deemed treatment related) compared with four patients on placebo (one of which was deemed treatment related). 

Twelve patients on Epidiolex discontinued treatment due to adverse events compared with one person on placebo. There was one death in the Epidiolex group, which was deemed unrelated to treatment. Of those who completed this trial, 100 percent have opted to continue into an open-label extension trial. 

Other Epidiolex trials

In addition to this first Phase 3 trial of Epidiolex in Lennox Gastaut syndrome, GW Pharmaceuticals is conducting a second Phase 3 dose-ranging trial of Epidiolex for the treatment of the condition, involving 225 people. Results are expected later this year.

Participants are also being enrolled to a second Phase 3 trial of Epidiolex in Dravet syndrome.

A phase 3 trial of Epidiolex in tuberous sclerosis complex has begun and a Phase 3 trial of Epidiolex in infantile spasms is expected to begin in the fourth quarter of the year.

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