The successful trial was for a potential treatment of Lennox-Gastaut Syndrome, a rare and severe type of childhood onset epilepsy.
In the trial Epidiolex, the drug, was given as an adjunct treatment to patients over a fourteen week period. The drug achieved the trials primary endpoint, which was to show a significant reduction in the monthly frequency of drop seizures compared to a placebo.
The trial results were described as “very exciting” by Linda Laux, who was an investigator for the trial and is director of the Comprehensive Epilepsy Center at the Ann & Robert H. Lurie Children's Hospital of Chicago.
“Lennox-Gastaut syndrome begins in early childhood, is particularly difficult to treat, and the vast majority of patients do not obtain an adequate response from existing therapies,” Laux said.
“These data show that Epidiolex has the potential to provide a robust and clinically meaningful reduction in seizures in this highly treatment-resistant population together with an acceptable safety and tolerability profile, which is consistent with my previous clinical experience with Epidiolex.”
The latest breakthrough follows earlier success, in March, of a separate trial using Epidiolex for another Epilepsy condition called Dravet syndrome.
Justin Gover, GW Pharmaceuticals chief executive, said: “We are delighted to announce positive results in this Phase 3 trial of Epidiolex in patients with Lennox-Gastaut syndrome, and particularly pleased that this result is consistent with our recent Phase 3 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.”
Gover said the company was now looking forward to the submission of a new drug application to the US Food and Drugs Administration in the first half of 2017.
In New York, GW Pharmaceutical American Depository Receipts (ADRs) advanced around US$9 or 11% to change hands at US$92.30. Meanwhile, in London, GW shares were up 74p or 14.6% at 580p.