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24 June 2014

Cannabis-based epilepsy drug shows promise

Epilepsy Society's medical director Professor Ley Sander  said preliminary tests in the US  into a cannabis-based drug for severe epilepsy in children show promise, but warned that only proper clinical trials would ensure the long-term efficacy and safety of the drugs.

Initial tests have shown that  many participants treated with the experimental drug have experienced a significant reduction in seizures.

Twenty-seven children and young adults whose seizures don't respond to conventional anti-epileptic medication have been treated with Epidiolex, a strawberry-lime flavoured syrup developed by the British pharmaceutical company GW Pharmaceuticals. The medication contains the compound cannabinoid (CBD), but does not contain any of the psychogenic  ingredient THC, associated with the marijuana 'high'.

Drug interactions

Professor Ley Sander said: 'It is important that we explore fully the tolerability of cannabinoids in people with epilepsy and that we test for potential interactions with other drugs.

'It is also essential to remember the dangers of smoking street cannabis. The cannabinoids being considered as potential treatment for epilepsy are not present in street cannabis. In some cases, smoking cannabis can have detrimental effects.'

Reduction in seizure frequency

The 12-week open-label study at two hospitals in the US have produced encouraging results, according to GW Pharmaceuticals, with a high proportion of participants showing a reduction in seizure frequency of more than 50 per cent, and 15 per cent of patients  reporting to be seizure free at the end of the 12 week period.

Patients in the study have a range of severe epilepsies including Dravet syndrome and Lennox-Gastaut syndrome. The 27 patients were predominantly children aged from 3-18, with one patient over the age of 26. In all cases, Epidiolex was given in addition to the participants' usual anti-epileptic drugs (AEDs). On average, patients were taking 2.7 other AEDs.

Safety data has been collated on 62 patients. These include an additional 35 patients who have begun treatment but not yet reached the 12 week milestone. The most common side effects included drowsiness, tiredness, diarrhoea and change in appetite.

GW Pharmaceuticals now plans to start a PhaseII/III  clinical trial.

Drug-resistant epilepsy

Orrin Devinsky is professor of neurology, neurosurgery, and psychiatry at New York University  School of Medicine, and director, NYU Comprehensive Epilepsy Center. He said:  'There remains an enormous unmet need in a range of paediatric and adult treatment-resistant epilepsy syndromes.  Some of the greatest needs are in children with severe epilepsy syndromes such as Dravet and Lennox-Gastaut, where frequent seizures often persist despite high doses of multiple anti-epileptic drugs.

'The initial open-label study with Epidiolex has provided encouraging results.  Some children have had marked reductions in their seizures and overall, the medication has been well tolerated.'

 

Tests begin on cannabis-based epilepsy drug