The US Food and Drug Administration (FDA) has given the thumbs up to a purified formulation of cannabidiol (CBD) (Epidiolex oral solution, GW Pharmaceuticals) for the treatment of seizures related to two rare forms of epilepsy in patients older than 2 years of age. The two types of epilepsy indicated are Lennox-Gastaut syndrome and Dravet syndrome.

"This is the first FDA-approved drug that contains a purified drug substance derived from marijuana," the agency announced in a press release. "It is also the first FDA approval of a drug for the treatment of patients with Dravet syndrome."

"This approval serves as a reminder that advancing sound development programs that properly evaluate active ingredients contained in marijuana can lead to important medical therapies," FDA Commissioner Scott Gottlieb, MD, said in the same release.

"The FDA is committed to this kind of careful scientific research and drug development," added Gottlieb.

He noted that marijuana-derived therapies are most appropriately brought to patients through strict clinical trials that assess both safety and efficacy, and then by going through the FDA's stringent drug approval process.

The current drug was evaluated in three randomized, placebo-controlled studies with a total of 516 patients evaluated — all with Dravet syndrome or Lennox-Gastaut syndrome. Results showed that add-on therapy with the CBD product was more effective than placebo in reducing seizure frequency.

Because of these "well-controlled" trials, which were published in the New England Journal of Medicine and Lancet, "prescribers can have confidence in the drug's uniform strength and consistent delivery that support appropriate dosing needed for treating patients with these complex and serious epilepsy syndromes," said Gottlieb.

Commonly reported adverse events in patients receiving the add-on treatment included elevated liver enzymes, sedation and lethargy, sleepiness, decreased appetite, fatigue, insomnia and poor sleep quality, infections and rash, and diarrhea.

Quality-of-Life Impact

Patients with Lennox-Gastaut syndrome often have seizures that begin as early as at age 3 years. More than 75% of patients with the syndrome experience tonic seizures; most children with it develop intellectual disabilities; and many patients have motor skill impairments.

Dravel syndrome affects babies during the first year of their life and causes frequent febrile seizures. As the patient ages, other types of seizures often occur, as does status epilepticus. These children also often have language and motor skill dysfunction.

"The difficult-to-control seizures that patients with Dravet syndrome and Lennox-Gastaut syndrome experience have a profound impact on these patients' quality of life," Billy Dunn, MD, director of the Division of Neurology Products in the FDA's Center for Drug Evaluation and Research, said in a statement.

"In addition to another important treatment option for Lennox-Gastaut patients, this first-ever approval of a drug specifically for Dravet patients will provide a significant and needed improvement in the therapeutic approach to caring for people with this condition," added Dunn. A patient medication guide, describing drug use and risks, will need to be included with all prescriptions.

As reported by Medscape Medical News, an FDA advisory committee voted unanimously in April to support approval of this drug.

"It's an honor to be part of a meeting that's making an important decision based on science and public input rather than a political discussion," panel member Mark W. Green, MD, professor of neurology, anesthesiology, and rehabilitation medicine at Icahn School of Medicine at Mt Sinai, New York City, said at the time.

CBD is currently classified as a Schedule I substance under the Controlled Substances Act, so the new product will need to be rescheduled before it can be made available to patients.

After evaluating a scheduled substance, the FDA provides recommendations to the US Drug Enforcement Administration (DEA). The DEA must then make a scheduling determination.

Dravet syndrome had been granted fast-track designation by the FDA, and both it and Lennox-Gastaut syndrome were indications granted orphan drug designation. Application for the current drug was granted priority review designation.

"Historic Milestone"

"Today's approval of Epidiolex is a historic milestone, offering patients and their families the first and only FDA-approved CBD medicine to treat two severe, childhood-onset epilepsies," Justin Gover, chief executive officer of GW Pharmaceuticals, said in its own press release.

"I often see patients with these highly treatment-resistant epilepsies who have tried and failed existing therapies and are asking about CBD," said Orrin Devinsky, MD, New York University Langone Health's Comprehensive Epilepsy Center, in the same release. Devinsky is also lead investigator in the Epidiolex Clinical Program.

He noted his relief that he and his colleagues "will now have the option of a prescription cannabidiol that has undergone the rigor of controlled trials and been approved by the FDA to treat both children and adults."

Philip Gattone, president and CEO of the Epilepsy Foundation, called the newly approved drug "a true medical advancement" in a statement.

"Clinical development for these rare and severe conditions is essential, and today's news brings hope for these patients and their families that a new treatment option may have the potential to help better control their seizures," said Gattone.

After it goes through rescheduling, which the company says is expected to occur within 90 days, "Epidiolex is expected to be available to appropriate patients by Fall 2018." A decision on approval recommendation by the European Medicines Agency is expected in the first quarter of 2019.

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