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14 March 2016

Cannabis-based epilepsy drug could soon be available on prescription in US

Epilepsy Society's medical director Professor Ley Sander has welcomed the latest results from the first placebo-controlled trial into the cannabis-based drug Epidiolex.

The results support the safety and efficacy of the medicinal liquid form of cannabis in the treatment of Dravet syndrome, a rare but severe childhood epilepsy. And they could now pave the way for the drug becoming the first FDA (Food and Drug Administration) approved treatment option in the US for children with the syndrome.

Dravet syndrome is one of the most hard-to-treat forms of epilepsy that usually begins in infancy and can result in children having as many as 100 seizures a day and cognitive disabilities.

In the 14-week treatment period of the study, patients taking Epidiolex achieved an average reduction in monthly convulsive seizures of 39 percent compared with a reduction of 13 percent for those patients taking a placebo drug.

Multiple seizures

Professor Ley Sander commented: 'The results from this trial show significant promise. Dravet syndrome is an extremely debilitating childhood epilepsy. Many of those with the condition have multiple seizures both day and night, and this can be a huge burden for the children, their families and carers.

'The huge amount of media interest in this drug and the repeated enquiries to paediatric clinicians reflect the desperation of parents who are hoping for a drug that will bring relief for their children.

'I do not think we can see Epidiolex as being a magic bullet that will deliver seizure freedom for all those with Dravet syndrome but I am hopeful that it will offer another treatment option with the possibility of better seizure control for some in the future. As with other treatment options, it is likely to offer seizure freedom or reduction for some but not all.'


Dr Ben Whalley, professor of neuropharmacology at the University of Reading, first identified and characterised the non-psychoactive components of cannabis  including cannabidiol which has been developed as Epidiolex by drug company, GW Pharmaceuticals.

Dr Whalley said: 'I am delighted to see this news as it represents the first properly objective demonstration of the efficacy of cannabidiol in human epilepsy and provides the much needed evidence required to apply for status as a licensed medicine. After over 15 years of preclinical work with this compound, it is incredibly gratifying to see a positive result in a pivotal trial.'

Listen to Dr Ben Whalley talk about the use of cannabis-based drugs in epilepsy.


Trial results

One hundred and 20 patients with an average age of 10 took part in the trials. Thirty per cent of patients were less than six years of age. The average convulsive seizure frequency per month was 13 at the start of the study.

As well as showing an average reduction in seizures of 39 per cent, the study showed Epidiolex to be generally well tolerated. The most common adverse events, occurring in more  than 10 per cent of those treated with Epidiolex, were: somnolence, diarrhoea, decreased appetite, fatigue, pyrexia (raised body temperature), vomiting, lethargy, upper respiratory tract infection and convulsion.

Of those patients on Epidiolex who reported an adverse event, 84 per cent reported it to be mild or moderate. Ten patients on Epidiolex experienced a serious adverse event compared with three patients on the placebo.

Eight patients on Epidiolex discontinued treatment due to adverse events compared with one patient on the placebo.

New drug application

Justin Gover, GW's chief executive officer said:  'In light of this positive data, we will now request a pre-NDA (new drug application) meeting with the FDA to discuss our proposed regulatory submission.'

Once approved in the US, GW will seek approval for the drug in Europe.

A second phase III trial in Epidiolex is now underway, involving 150 patients, and trials are awaited for two phase III trials for the treatment of Lennox-Gestaut syndrome - another childhood syndrome - with Epidiolex.