Around the globe there is high interest in the use of cannabidiol (CBD), a type of cannabinoid, for the treatment of people with epilepsy, especially children who have treatment-resistant forms of the disorder such as Lennox-Gastaut Syndrome (LGS) and Dravet Syndrome (DS). Three studies presented at the American Epilepsy Society's 69th Annual Meeting in Philadelphia highlight emerging efficacy and safety data of Epidiolex, a pharmaceutical liquid formulation of cannabidiol, which is currently undergoing U.S. Food and Drug Administration (FDA) authorized Phase 3 pivotal clinical trials in the United States and across the globe by GW Pharmaceuticals. A fourth study highlights possible interactions of CBD with existing anti-epileptic drugs (AEDs) in animal models of seizures. The largest CBD study presented efficacy and safety data on GW Pharmaceutical's investigational medicine, Epidiolex (cannabidiol) from open-label Expanded Access programs at 16 sites. The study (abstract 3.034) involves 261 people, predominantly children, who have severe epilepsy that had not responded adequately to other treatments. The average age of the participants was 11. Over the course of 12 weeks, the study participants were given Epidiolex in gradually increasing doses. In all cases, Epidiolex was added to current AED treatment regimes. On average, patients were taking approximately three other AEDs. Participants and their families/caregivers recorded the number of seizures prior to taking CBD and during the 12 weeks of treatment. Clinicians also tested hematologic, liver and kidney function as well as AED levels before treatment and then at four, eight and 12 weeks during the study.

After three months of treatment, the frequency of all seizures was reduced by a median of 45 percent in all participants. Almost half (47%) of the participants in the study experienced a 50 percent or greater reduction in seizures and nine percent of patients were seizure-free. Among specific patient populations, DS patients had a 62 percent reduction in seizures and 13 percent were seizure-free. Patients with LGS experienced a 71 percent reduction in atonic seizures. 

Adverse events occurred in more than 10 percent of participants with the most common being somnolence, diarrhea and fatigue and led to discontinuation in 4 percent of patients. Thirty-four percent of participants reported serious adverse events of which 5 percent were considered treatment related including altered liver enzymes (n=4), status epilepticus (n=4), diarrhea (n=4) and others. Twelve percent withdrew from the study for lack of efficacy.

"We are pleased to report these promising data on significant numbers of children," said lead author Orrin Devinsky, M.D., of New York University Langone Medical Center's Comprehensive Epilepsy Center. "These data reinforce and support the safety and efficacy we have shared in previous studies. Most importantly it is providing hope to the children and their families who have been living with debilitating seizures."