F.D.A. Panel Recommends Approval of Cannabis-Based Drug for Epilepsy

WASHINGTON — A Food and Drug Administration advisory panel on Thursday unanimously recommended approval of an epilepsy medication made with an ingredient found in marijuana. If the agency follows the recommendation, as is expected, the drug would be the first cannabis-derived prescription medicine available in the United States.

The drug, called Epidiolex, is made by GW Pharmaceuticals, a British company. Its active ingredient, cannabidiol, also called CBD, is one of the chemical compounds found in the cannabis plant, but it does not contain the properties that make people high.

That makes it different from the “medical marijuana” allowed by a growing number of states. In those cases, certain patients are legally authorized to smoke or ingest marijuana to treat severe pain, nausea and other ailments.

There are already several drugs on the market that are derived from synthetic versions of THC and other chemicals of the cannabis plant, generally used to ease nausea in cancer patients, and to help AIDS patients avoid weight loss.

Advocates for development of marijuana-based treatments, and those pushing for better treatments of epilepsy, were pleased with the panel’s recommendation.

“This is a very good development, and it basically underscores that there are medicinal properties to some of the cannabinoids,” said Dr. Igor Grant, director of the Center for Medicinal Cannabis Research at the University of California San Diego. “I think there could well be other cannabinoids that are of therapeutic use, but there is just not enough research on them to say.”

The panel recommended approval of the drug to treat two rare forms of epilepsy — Lennox-Gastaut syndrome and Dravet syndrome. They are among the most difficult types of epilepsy to treat, with nearly all patients continuing to have seizures despite currently available medications, according to the F.D.A. The large number of seizures — experts say a person can have multiple episodes a day — puts children at high risk for intellectual and developmental disabilities, as well as death. Lennox-Gastaut syndrome usually appears between ages three and five years, and Dravet syndrome earlier.

There are an estimated 30,000 children and adults with Lennox-Gastaut syndrome and fewer than that with Dravet syndrome. Because the conditions are so rare, GW Pharmaceuticals has received an orphan drug designation for Epidiolex.

“It’s very important that we have additional treatments because these patients have very, very difficult to control seizures,” said Dr. Jerzy P. Szaflarski, a neurology professor at the University of Alabama at Birmingham, who directs the university’s epilepsy division. “I get questions about cannabidiol almost every day.”

The briefing materials prepared for the committee by F.D.A. staff made it clear that the agency supports the application. The F.D.A. wrote that GW Pharma had submitted positive results of efficacy from three randomized, double-blind, placebo-controlled trials conducted in patients with both diseases.

“The statistically significant and clinically meaningful results from these three studies provide substantial evidence of the effectiveness of CBD for the treatment of seizures associated with LGS and DS,” the agency noted.

The briefing papers also reported risk of a potentially serious side effect — liver injury — but said it could be managed.

Epidiolex would be the first of a new class of drugs to treat epilepsy. The F.D.A. is not bound by advisory committee recommendations but often follows them.

Christina SanInocencio, a nurse and founder of the LGS Foundation, hopes it does.

“I have a brother with the disorder,” Ms. SanInocencio said. “I’ve met hundreds and hundreds of families who have kids living with it. It’s so devastating. Any new medicine that comes to the market is a really big win for our community.”