A Phase 3 study presented at the American Academy of Neurology's Annual Meeting in Philadelphia has provided new evidence of the benefits of pharmaceutical-grade cannabidiol (Epidiolex) in treating Dravet Syndrome. Dravet Syndrome is an infantile onset developmental and epileptic encephalopathy associated with drug-resistant seizures.
Among the results presented was the finding that an add-on dose of 10 milligrams per kilogram of body weight, taken daily, is as effective as the 20 mg/kg per day dose previously studied.
The study involved 199 children with Dravet syndrome with an average age of 9. The children had already tried an average of four epilepsy drugs with no success and at the time of the study were taking an average of three additional drugs. Cannabidiol was used as an add-on to existing drugs.
Participants were divided into three groups. One group received 20 milligrams per kilogram (mg/kg) per day of cannabidiol, the second group received 10 mg/kg per day and the third group received a placebo.
Seizures were recorded for four weeks before the treatments were started to establish a baseline. Then the participants received the treatment for 14 weeks. By the end of the study, seizures with convulsions had decreased for those taking the high dose of the drug by 46% and by 49% for those taking the lower dose of the drug, compared to 27% for those taking the placebo.
Total seizures reduced by 47% for those in the high dose group, by 56% for those in the lower dose group and by 30% for those in the placebo group. In the high dose group, 49% of the participants had their seizures cut in half or more, compared to 44% in the low dose group and 26% in the placebo group.
All of the groups reported side effects, with 90% of the high dose group, 88% of the low dose group and 89% of the placebo group. The most common side effects were decreased appetite, diarrhea, sleepiness, fever and fatigue. About 25% of those in the high dose group had serious side effects, compared to 20% of those in the low dose group and 15% of those in the placebo group. Only participants in the high dose group stopped taking the drug due to side effects; that number was 7%.
Study author Dr. Ian Miller of Miami's Nicklaus Children's Hospital said "Based on these results, dose increases above 10 mg/kg per day should be carefully considered based on the effectiveness and safety for each individual”.
He added that the study was limited, however, because its focus was on a specific type of epilepsy and type of cannabidiol: the highly purified, plant-derived pharmaceutical formulation of cannabidiol called Epidiolex.
"Further studies are needed to scientifically demonstrate how other forms of epilepsy or other forms of cannabidiol or cannabis affect seizures," he said.
The study was supported by GW Research Ltd.
Further information: Download AAN Abstract here.