Lennox-Gastaut syndrome is a rare, severe form of epilepsy that is often resistant to treatment. Preclinical data have shown the cannabis derivative, cannabidiol, to have activity against seizures.
In a paper in The Lancet (online, 24 January 2018), researchers randomly assigned 171 patients with treatment-resistant Lennox-Gastaut syndrome to a daily dose of 20mg/kg oral cannabidiol as an add-on therapy, or placebo
. Patients who had at least two drop seizures (sudden falls due to seizures) per week during a four-week baseline period were eligible for the study.
Over the 14-week treatment period, the monthly frequency of drop seizures decreased by a median of 43.9% from baseline in the cannabidiol group compared with 21.8% in the placebo group. Over 80% of participants who received cannabidiol experienced side effects, compared with 69% in the placebo group, but these were mostly mild or moderate in severity.
The team said the results indicated a clinically meaningful reduction in seizure frequency, and is now exploring the long-term safety of oral cannabidiol.
 Thiele E, Marsh E, French J et al. Cannabidiol in patients with seizures associated with Lennox-Gastaut syndrome (GWPCARE4): a randomised, double-blind, placebo-controlled phase 3 trial. Lancet 2018. doi: 10.1016/S0140-6736(18)30136-3