Successful Phase III study of Epidiolex (cannabidiol) for the treatment of Dravet syndrome- GW Pharma

GW Pharmaceuticals plc announced the positive results of the first pivotal Phase III study of its investigational medicine Epidiolex (cannabidiol or CBD) for the treatment of Dravet syndrome. In this study, Epidiolex achieved the primary endpoint of a significant reduction in convulsive seizures assessed over the entire treatment period compared with placebo (p=0.01).

The Phase III study randomized 120 patients into two arms, Epidiolex 20mg/kg/day (n=61) and placebo (n=59). Epidiolex or placebo was added to current anti-epileptic drug (AED) treatment regimens. On average, patients were taking approximately 3 AEDs, having previously tried and failed an average of more than 4 other AEDs. The average age of trial participants was 10 years and 30 percent of patients were less than 6 years of age. The median baseline convulsive seizure frequency per month was 13. The primary efficacy endpoint was a comparison between Epidiolex and placebo measuring the percentage change in the monthly frequency of convulsive seizures during the 14-week treatment period compared with the 4-week baseline observation period.

In this study, patients taking Epidiolex achieved a median reduction in monthly convulsive seizures of 39% compared with a reduction on placebo of 13% (p=0.01). A series of sensitivity analyses of the primary endpoint 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 effectiveness observed with Epidiolex. Epidiolex was generally well tolerated in this study.

Comment: Epidiolex is a liquid formulation of cannabidiol, derived from the cannabis plant, that GW believes can reduce seizures in some severe forms of childhood epilepsy. GW Pharma is planning to request a meeting with the FDA to devise a way to submit Epidiolex for approval.