LONDON, Feb. 28, 2014 (GLOBE NEWSWIRE) -- GW Pharmaceuticals plc (AIM:GWP) (Nasdaq:GWPH) ("GW") announced today that the U.S. Food and Drug Administration (FDA) has granted orphan drug designation for Epidiolex®, GW's product candidate that contains plant-derived Cannabidiol (CBD) as its active ingredient, for use in treating children with Lennox-Gastaut syndrome (LGS), a rare and severe form of childhood-onset epilepsy. Epidiolex is an oral liquid formulation of a highly purified extract of CBD, a non-psychoactive molecule from the cannabis plant. In November 2013, GW announced that the FDA had granted orphan drug designation for Epidiolex in the treatment of Dravet syndrome. Following the successful follow-on offering completed in January 2014, GW intends to advance a full clinical development program for Epidiolex for the treatment of both LGS and Dravet syndromes. Working with leading pediatric epilepsy specialists in the United States, GW expects to commence an initial Phase 2 clinical trial for Epidiolex in the second half of 2014. This trial, if successful, is expected to lead to Phase 3 pivotal trial programs in both Dravet syndrome and LGS intended to support New Drug Applications with the FDA. LGS is a severe form of childhood-onset epilepsy. Seizure types, which vary among patients, include tonic (stiffening of the body, upward deviation of the eyes, dilation of the pupils, and altered respiratory patterns), atonic (brief loss of muscle tone and consciousness, causing abrupt falls), atypical absence (staring spells), and myoclonic (sudden muscle jerks). Most children with LGS experience some degree of impaired intellectual functioning or information processing, along with developmental delays, and behavioral disturbances. LGS can be caused by brain malformations, perinatal asphyxia, severe head injury, central nervous system infection and inherited degenerative or metabolic conditions. It is estimated that there are approximately 14,000-18,500 patients with LGS in the United States and 23,000-31,000 patients with LGS in Europe.