More Evidence That Weed Extract Effectively Treats Epilepsy in Children

A large clinical trial has presented the most promising results to date that a derivative of marijuana can help control seizures in children with a form of epilepsy, according to a study published Wednesday in the New England Journal of Medicine.

For children with severe forms of epilepsy, the disease can be a prison. There are some treatments, but they don't work for everyone. If the condition isn't effectively treated, children have hundreds of seizures a day, inhibiting them from doing the kinds of things normal kids like to do. One of the most severe forms, called Dravet syndrome, comes from a rare genetic mutation and is characterized by frequent and prolonged seizures within a child's first year; 20 percent of children with Dravet syndrome die, either unexpectedly or due to accidents that occur during seizures.

There have been a few highly publicized cases of children with Dravet syndrome whose symptoms had been eased by cannabidiol (CBD), a compound in marijuana that makes smokers feel relaxed and calm. These cases were interesting to researchers, but they weren't enough to show them if the treatment would work for everyone with Dravet; a few small clinical trials yielded mixed results.

An international team of researchers decided to collect some data to see if the conclusions from the anecdotes held true. This study, the first large randomized clinical trial of CBD to treat epilepsy, built on the researchers' previous work with CBD and epilepsy; an exploratory study published in January 2016 in The Lancet Neurology found similarly promising results, but focused on a different group of children with epilepsy and lacked a control group. The publicized anecdotes of children with Dravet syndrome, and because the condition is relatively easy to identify by its genetic mutation, made that disease a good place to start, says Daniel Friedman, associate professor of neurology at NYU Langone Medical Center and one of the authors of the current study.

Friedman, along with researchers from 23 centers in the US and Europe, randomly assigned 120 children between the ages 2 to 18 with Dravet syndrome to take an oral CBD medication called Epidiolex, or to take a placebo instead, in addition to their existing drug regimen. The children took the placebo or the dose of Epidiolex (how much depended on the participant's body weight) twice a day for 14 weeks; during that period, their parents recorded how many seizures they had and what type. The patients underwent periodic medical assessments to check for side effects. The researchers asked parents and caregivers to track the number of seizures each patient had per day, and to gauge whether the child's condition improved overall. The researchers included this subjective assessment because "it may capture other aspects of wellbeing that may or may not be related to seizures," Friedman says.

Epidiolex had a clear benefit. The median number of seizures for children on the drug dropped dramatically; 43 percent of the patients taking Epidiolex had just half the number of seizures they had before the trial started. The condition improved in 62 percent of the patients on Epidiolex, according to their caregivers (34 percent of the patients in the control group were said to have improved on placebo). Five percent of the patients on Epidiolex were seizure-free, while zero percent were in the control group.

The drug wasn't universally beneficial. Three quarters of Epidiolex patients had negative side effects, such as nausea, vomiting, and drowsiness, though relatively few were severe. Nine patients withdrew from the study before it ended, almost all because of the side effects. But it's not clear if these adverse effects were from the CBD itself, from other components in the oil, or because the drug interacted with others the patients were taking in the body (it's nearly impossible to parse out this last point, Friedman says, due to ethical concerns about taking children off medications that are providing some benefit).

The results added much-needed data to the well-known anecdotes of epilepsy patients treated with CBD, writes Samuel Berkovic, a professor of medicine at the University of Melbourne, in an editorial accompanying the study in the New England Journal of Medicine. "This trial represents the beginning of solid evidence for the use of cannabinoids in epilepsy. It requires replication," he writes.

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And though it's a good start, there's more data needed. The researchers still have questions about the effects of long-term use of CBD. There would need to be more studies to show that CBD could treat other forms of epilepsy, as researchers suspect it might. Luckily, the researchers recently completed two more studies for Epidiolex—a second one for Dravet syndrome and another to treat a different type of severe childhood epilepsy called Lennox-Gastaut syndrome—and are currently analyzing the data. The preliminary results are positive, Friedman says.

Even if future studies do show that CBD is an effective treatment for epilepsy, not everyone has access to it. Patients currently have to travel abroad, enter into clinical trials, or risk legal action to get the drugs they need. The laws surrounding medicinal marijuana in the United States are changing, though perhaps not fast enough for some patients who are suffering now. A more likely scenario is that, with the right kind of evidence, Epidiolex could get approved by the Food and Drug Administration, but marijuana, which contains its active ingredient, could still be legally restricted on a national level.

"The only way to potentially get out of this quagmire is to rethink how we regulate recreational cannabis on a national level without having these carve-outs," Friedman says, referring to states where recreational marijuana is legal. "That's going to be a long discussion that I'm happy to not to have to participate in."

Some of Friedman's patients are already asking him if they can drop their current medication regimens in favor of CBD. "We don't know that yet. We don't know how effective this will be alone," he tells them. Future studies may provide a more definitive answer.

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