GW Pharmaceuticals and its US subsidiary Greenwich Biosciences have completed the rolling submission of Epidiolex as adjunctive treatment of seizures associated with Lennox-Gastaut syndrome and Dravet syndrome, two difficult-to-treat forms of childhood-onset epilepsy.

The submission is “an important milestone for patients with LGS and Dravet syndrome in that a potential new treatment option is within sight for these very difficult to treat and devastating conditions," said Justin Gover, GW’s chief executive.

The application is supported by data from three Phase III studies, all of which met their primary efficacy endpoints and showed the drug to be generally well tolerated. It also includes comprehensive clinical pharmacology, pre-clinical and toxicology data.

Epidiolex, GW's lead cannabinoid product candidate, is a pharmaceutical formulation of purified cannabidiol (CBD), which is in development for the treatment of several rare childhood-onset epilepsy disorders.

The company said it also plans to file a similar Marketing Authorisation Application in Europe for Epidiolex “in the near future”.