By Pat Anson, Editor

A British pharmaceutical company has reported positive results from a Phase 3 clinical study of a marijuana-based medication for Dravet syndrome, a severe form of children’s epilepsy.

The study found that Epidiolex, a liquid formula containing a plant-derived cannabinoid (CBD), significantly reduced the number of seizures in children with Dravet syndrome. CBD is a compound in cannabis that does not produce the “high” caused by marijuana.

The study findings caused shares of GW Pharmaceuticals (NASDAQ: GWPH) to more than double in trading Monday, much of it fueled by speculation that the company’s cannabinoid products would eventually be approved by the Food and Drug Administration for pain relief.

“If they get this, doctors will say, here’s a cannabinoid prescription,” said CNBC’s Jim Cramer. “This will be the pure cannabis that a lot of people who have been waiting for, an actual painkiller that is not addictive. This will replace, I believe, the terrible, terrible wave of death that oxycodone has caused.

“If you want to prescribe actual medical marijuana, a real doctor is reluctant to do it because there are no uniform standards, and what you really want is the pure cannabinoid. There will be use of this galore.”

In a statement to CNBC, GW said it was not investigating Epidiolex for pain relief.

"Today's Phase 3 results of Epidiolex (cannabidiol) were not studying the medicine as a possible treatment for pain. Epidiolex is being investigated for Dravet syndrome, Lennox-Gastaut syndrome and Tuberous Sclerosis Complex (TSC), three rare, extremely debilitating epilepsy syndromes that begin in infancy or early childhood," the company said.

The Phase 3 placebo controlled study involved 120 children with Dravet syndrome, who were averaging about 13 seizures a month before the trial began. Seizures declined by over a third in patients treated with Epidiolex, with few side effects.

“The results of this Epidiolex pivotal trial are important and exciting as they represent the first placebo-controlled evidence to support the safety and efficacy of pharmaceutical cannabidiol in children with Dravet syndrome, one of the most severe and difficult-to-treat types of epilepsy,” said Orrin Devinsky, MD, of New York University Langone Medical Center’s Comprehensive Epilepsy Center.

“These data demonstrate that Epidiolex delivers clinically important reductions in seizure frequency together with an acceptable safety and tolerability profile, providing the epilepsy community with the prospect of an appropriately standardized and tested pharmaceutical formulation of cannabidiol being made available by prescription in the future.”

Epidiolex has both Orphan Drug Designation and Fast Track Designation from the U.S. Food and Drug Administration. There are currently no approved treatments for Dravet syndrome in the U.S.

“We are excited about the potential for Epidiolex to become the first FDA approved treatment option specifically for Dravet syndrome patients and their families,” said Justin Gover, GW’s CEO. “In light of this positive data, we will now request a pre-NDA (new drug application) meeting with the FDA to discuss our proposed regulatory submission.”

GW is recruiting 150 patients for a second Phase 3 trial of Epidiolex for Dravet syndrome and is currently conducting a Phase 3 study for Lennox-Gastaut syndrome. Another study of Epidiolex is scheduled to begin soon for a third form of epilepsy, Tuberous Sclerosis Complex.

The company is already marketing a marijuana-based oral spray called Sativex that is being sold in Europe, Canada and Mexico to treat muscle tightness and contractions caused by multiple sclerosis. Canada also allows Sativex to be used for the treatment of neuropathic pain and advanced cancer pain.

Sativex is not currently approved for use in the U.S. for any condition. It is estimated that over 400,000 cancer patients in the U.S. suffer from pain that is not well controlled by opioid pain medications. Two recent Phase 3 studies found that Sativex worked no better than a placebo in treating cancer pain.