Topline results from a pivotal phase 3 trial show patients taking an investigational product containing pure cannabidiol (Epidiolex, GW Pharmaceuticals) had a highly statistically significant reduction in convulsive seizures compared with those receiving placebo, the company has announced.
The study found that patients receiving active treatment had a median reduction in monthly convulsive seizures of 39% compared with a 13% reduction for children taking placebo (P = .01).
These results “are important and exciting as they represent the first placebo-controlled evidence to support the safety and efficacy of pharmaceutical cannabidiol in children with Dravet syndrome,” said Orrin Devinsky, MD, New York University Langone Medical Center’s Comprehensive Epilepsy Center, in a press release.
Dravet syndrome is a rare and severe form of epilepsy in children. No treatments are currently approved by the US Food and Drug Administration (FDA) for this condition.
After a 4-week baseline observation period, researchers randomly assigned 120 children, average age 10 years and a median of 13 convulsive seizures per month, to 14 weeks of treatment with the cannabidiol product, 20 mg/kg/day (n = 61), or placebo (n = 59).
The treatment or placebo was added to antiepileptic drugs (AEDs) the patients were already taking. On average, patients were taking about three AEDs, having previously tried and not responded to an average of more than 4 other AEDs.
In addition to the study finding a highly statistically significant difference in median reduction in monthly convulsive seizures between those receiving treatment and placebo, a series of sensitivity analyses confirmed the robustness of this result.
The difference between Epidiolex and placebo emerged during the first month of treatment and was sustained during the entire treatment period. Results from secondary efficacy endpoints reinforced the overall findings of effectiveness.
The treatment was generally well tolerated, the company reports. The most common adverse events, occurring in greater 10% of treated patients, included somnolence, diarrhea, decreased appetite, fatigue, pyrexia, vomiting, lethargy, upper respiratory tract infection, and convulsion.
“The data demonstrate that Epidiolex delivers clinically important reductions in seizure frequency together with an acceptable safety and tolerability profile, providing the epilepsy community with the prospect of an appropriately standardized and tested pharmaceutical formulation of cannabidiol being made available by prescription in the future,” commented Dr Devinsky.
The product has both Orphan Drug Designation and Fast Track Designation from the FDA in the treatment of Dravet syndrome.
“We are excited about the potential for Epidiolex to become the first FDA approved treatment option specifically for Dravet syndrome patients and their families,” said Justin Gover, GW’s chief executive officer, in the press release.
In light of these positive data, the company plans to request a pre-New Drug Application meeting with the FDA to discuss its proposed regulatory submission.
GW is conducting a second phase 3 trial in Dravet syndrome that is recruiting 150 patients, as well as phase 3 trials in Lennox-Gastaut syndrome, another severe form of epilepsy affecting children.
Full results will be presented at upcoming medical meetings and future publications, the company notes.
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