GW Pharmaceuticals plc, a biopharmaceutical company focused on discovering, developing and commercializing novel therapeutics from its proprietary cannabinoid product platform, announces it has initiated the Phase 3 part of a Phase 2/3 clinical trial of Epidiolex® (cannabidiol or CBD) for the treatment of Dravet syndrome, a rare and catastrophic treatment-resistant form of childhood epilepsy. GW anticipates that top-line data from this trial will be available around the end of 2015.

"Dravet syndrome is a rare and catastrophic form of pediatric epilepsy in which there is a substantial unmet need and for which there are no specifically approved medicines in the United States," stated Orrin Devinsky MD, Professor of Neurology, Neurosurgery, and Psychiatry at NYU School of Medicine, and Principal Investigator of the trial. "This Phase 3 clinical trial of Epidiolex in Dravet syndrome is the first ever rigorous placebo-controlled trial of pure pharmaceutical cannabidiol (CBD) in the field of epilepsy and, as such, a trial of significant interest for the entire epilepsy physician and patient communities."

"GW is dedicated to developing Epidiolex for Dravet syndrome as rapidly as possible. As such, the start of the first Dravet syndrome Phase 3 trial is a significant milestone for our Company and we are on track to start the second Phase 3 trial very shortly," stated Justin Gover, GW's Chief Executive Officer. "We look forward to working with epilepsy physicians across the United States to execute this program with the objective of submitting a New Drug Application for Epidiolex to the FDA in mid-2016."

The Phase 3 trial is the second part of a two-part randomized double-blind, placebo-controlled parallel group safety, tolerability, pharmacokinetic and efficacy trial of Epidiolex to treat Dravet syndrome in children who are being treated with other anti-epileptic drugs. Part one completed in February 2015 and comprised the pharmacokinetic and dose-finding elements of the trial in a total of 34 patients over a three week treatment period. The dose for part two has been determined as 20mg/kg by a Data Safety Monitoring Committee (DSMC) after assessment of the part one safety and pharmacokinetic data.

Part two is a 14-week comparison of Epidiolex versus placebo in a total of 100 patients to assess the safety and efficacy as an adjunctive antiepileptic treatment. The primary measure of this trial will be the percentage change from baseline in convulsive seizure frequency during the maintenance period of the study in patients taking Epidiolex versus placebo. Several additional efficacy and safety secondary outcome measures will be analysed. Part two will recruit an entirely new group of patients who did not participate in part one. Following their participation in the study, all patients are eligible to receive Epidiolex under a long term open label extension study.

GW anticipates commencing the second pivotal Phase 3 trial in Dravet syndrome soon after this first trial, which will run in parallel with this Phase 2/3 trial. The Company also expects to commence two Phase 3 clinical trials in Lennox-Gastaut syndrome early in the second quarter of 2015. These additional pivotal trials are all expected to complete recruitment in 2015.

To obtain information about this clinical trial or eligibility criteria, the treating physician should contact: medicaldirector@gwpharm.com