Disclaimer: Epilepsy Research UK is completely neutral and is not affiliated with any pharmaceutical company, or any particular drug compound.GW Pharmaceuticals has announced positive results from a pivotal phase three clinical trial of Epidiolex (cannabidiol or CBD) in the treatment of Lennox-Gastaut syndrome (LGS), a rare form of childhood epilepsy.The announcement comes days after the company revealed plans to test the same drug in another form of childhood epilepsy, called infantile spasms or West’s syndrome.GW Pharmaceuticals hopes to submit a new drug application for Epidiolex to the US Food and Drug Administration (FDA) during the first half of 2017.In a press release, the CEO of GW Pharmaceuticals, Justin Gover, said: “We are delighted to announce positive results in this Phase three trial of Epidiolex in patients with Lennox-Gastaut syndrome, and particularly pleased that this result is consistent with our recent Phase three pivotal data for Epidiolex in Dravet syndrome. We believe that this result further demonstrates that Epidiolex offers the potential to be a new effective therapy within the field of treatment-resistant childhood-onset epilepsies.”The phase three clinical trial enrolled 171 participants, aged two to 55 years, with drug-resistant LGS. All participants were already taking one or more antiepileptic drug (AED). The participants were randomly divided into two groups, one in which people were given Epidiolex on top their existing AED(s), and the and the other in which subjects were given a placebo instead of Epidiolex. Neither the clinicians nor the participants knew who was in which group (a method used to avoid bias known as double-blinding).The results showed that at the end of a 14-week period, participants who took  Epidiolex together with their existing AED(s) had a monthly reduction in seizures of 44%, compared to 22% in the placebo group.The study also showed that Epidiolex was generally well-tolerated. The most common side effects were diarrhoea, somnolence, decreased appetite, high temperature, and vomiting.Epidiolex is also being trialled in another form of childhood-onset epilepsy called Dravet syndrome, and GW Pharmaceuticals announced positive results earlier this year from a phase three clinical trial for this condition. The company is planning to start a phase three clinical trial testing Epidiolex in people with infantile spasms towards the end of 2016.LGS is a type of childhood onset epilepsy affecting approximately one in 50,000 children in the UK. It usually appears when a child is between two to six years old. LGS is characterised by frequent seizures of different types and it is difficult to treat. It is often accompanied by cognitive delay, and psychological and behavioural problems.Author: Dr Özge ÖzkayaClick here for more articles about epilepsy in children.