Research in context
Evidence before this study
We searched PubMed for English-language studies published between Jan 1, 1973, and June 1, 2017, using the search terms “cannabidiol” AND “(epilepsy OR seizures OR anticonvulsant)”. Preclinical data have shown that cannabidiol has activity against seizures in in-vitro and in-vivo models. An open-label expanded access programme has indicated that GW Pharmaceutical's (Cambridge, UK) specific formulation of cannabidiol might be safe and efficacious in children and young adults with drug-resistant epilepsy, and results from a previous multicentre, randomised, placebo-controlled trial have suggested the formulation might also be safe and efficacious in children with Dravet syndrome.
Added value of this study
This is the first randomised, placebo-controlled trial to assess the efficacy and safety of a pharmaceutical formulation of purified cannabidiol as add-on therapy to existing antiepileptic drugs for the treatment of seizures associated with Lennox-Gastaut syndrome in children and adults.
Implications of all the available evidence
In addition to the available evidence, the results of this randomised, placebo-controlled trial suggest that the use of cannabidiol (20 mg/kg daily) as an add-on therapy for existing antiepileptic drug regimens might significantly reduce the frequency of seizures in patients with Lennox-Gastaut syndrome. The results also indicate that cannabidiol might lead to additional adverse events, but in general it appears to be well tolerated.