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19 May 2014

Tests begin on cannabis-based epilepsy drug

Epidiolex, an oral  liquid cannabis-derived medicine with the potential to reduce or control seizures, is being studied in over 300 children in the US who do not respond adequately to current anti-epileptic medications.The physician-sponsored studies are being carried out at 12 locations across the US and are the first CBD studies to receive authorisation from the US Food and Drug Administration.

Epidiolex is a highly purified extract of cannabidiol or CBD, a non-psychoactive molecule from the cannabis plant. This means that it does not produce the psychogenic properties most commonly associated with consumption of the plant.

The drug has been developed by GW Pharmaceuticals who are investigating Epidiolex as a treatment for two rare and severe forms of childhood epilepsy - Dravet syndrome and Lennox-Gestaut syndrome.

At the same time, scientists at Edinburgh University and the Royal Hospital for Sick Children in Edinburgh are also applying for approval to carry out a UK-based trial on Epidiolex. The trial will be led by Edinburgh but will also involve Great Ormond Street Hospital.

Scientists at the University of Reading, led by Dr Ben Whalley, have spent 10 years conducting the preclinical research into this potential new treatment for epilepsy that has led to these human clinical trials. They have been studying isolated compounds, including CBD, from the cannabis plant.  Isabelle Peres, a PhD researcher at the Schools of Pharmacy and Psychology and Clinical Language Sciences, described their findings so far as 'profound and highly encouraging.'

Cannabis-based drug could be as effective as valproic acid

In pre-clinical studies, Isabelle and colleagues have already shown that these components of cannabis can reduce the frequency and severity of seizures without affecting cognitive and motor abilities.  'They are proving to be equally as effective as some of the most widely used  anti-epileptic drugs such as valproic acid,' she said.

Researchers hope that the clinical trials in the States will provide the evidence needed to support that the drug is safe and well tolerated in humans and so allow full efficacy trials to take place.

While there is growing anecdotal evidence to suggest that an oil extracted from cannabis flowers could help reduce the frequency and severity of seizures in children with severe forms of treatment-resistant epilepsy, to date no placebo-controlled clinical studies for the use of the controversial form of medication have been undertaken.

Reduction in seizures

The results of a small parent survey from the University of Stanford, published in the journal Epilepsy and Behavior, showed that 84 per cent of the 19 parents using a CBD-rich cannabis extract to help control their children's seizures, reported a reduction in seizures, with  42 per cent reporting a greater than 80 per cent reduction in seizures. Eleven per cent reported complete seizure freedom 

Although some children experienced drowsiness, others reported better mood and alertness.

Isabelle Peres continued:  'It is essential that we now conduct the robust and objective clinical research needed to confirm the efficacy of these non-psychoactive cannabinoids in the treatment of epilepsy. '

Cannabis in the management and treatment of seizures and epilepsy: a scientific review by Dr Ben Whalley (The American Herbal Pharmacopoeia)