An experimental drug derived from marijuana has succeeded in reducing epileptic seizures in its first major clinical trial, the product’s developer announced on Monday, a finding that could lend credence to the medical marijuana movement.
The developer, GW Pharmaceuticals, said the drug, Epidiolex, achieved the main goal of the trial, reducing convulsive seizures when compared with a placebo in patients with Dravet syndrome, a rare form of epilepsy. GW shares more than doubled on Monday.
If Epidiolex wins regulatory approval, it would be the first prescription drug in the United States that is extracted from marijuana. The drug is a liquid containing cannabidiol, a component of marijuana that does not make people high.
As many as 30 percent of the nearly 500,000 American children with epilepsy are not sufficiently helped by existing drugs, according to GW. Parents of some of these children have been flocking to try marijuana extracts, prepared by medical marijuana dispensaries.
A number of states, in response to pressure from these parents, have passed or considered legislation to make it easier to obtain marijuana-based products. And some families have become “marijuana refugees,” moving to Colorado where it has been easier to obtain a particular extract, known as Charlotte’s Web, after the girl who first used it to control seizures.
Hundreds of other children and young adults have been using Epidiolex outside of clinical trials, under programs that allow desperate patients to use experimental drugs.
While many parents have reported significant reductions in seizures, experts have been cautious about anecdotal reports, saying that such treatments needed to be compared with a placebo to make sure they work. As such, the results from the GW trial have been closely watched.
“I’m very proud and happy about this study because it is science — we did things the way they should be done,” the study’s lead investigator, Dr. Orrin Devinsky of the Comprehensive Epilepsy Center at New York University Langone Medical Center, said in an interview. “I would strongly advocate that in the United States we need to do systematic assessments of medical marijuana.”
The study involved 120 patients with an average age of 10 and an average frequency of 13 convulsive seizures a month at the start of the study, despite taking an average of three other drugs. Half of the children were randomly assigned to take the drug and the other half the placebo, in addition to the epilepsy medicines they were already taking.
The company said that for the patients who received Epidiolex, the frequency of convulsive seizures fell by 39 percent during the 14-week treatment period, compared with a four-week period just before the treatment started. For those getting the placebo, the reduction was 13 percent. The difference between the two groups was statistically significant.
Eight patients getting Epidiolex and one getting the placebo withdrew from the trial because of side effects. Major side effects included drowsiness, diarrhea, decreased appetite, fatigue, fever, vomiting and upper respiratory infection. But GW said that over all, the drug was well tolerated.
One caution is that the full details of the study were not released; the company said they would be presented at a medical conference.