FDA to Give GW Pharmaceuticals’ Cannabis-based Therapy for Dravet Syndrome a Priority Review

Patricia Inácio, PhD avatar

by Patricia Inácio, PhD |

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Dravet therapy review

The U.S. Food and Drug Administration will give priority review to a New Drug Application that GW Pharmaceuticals submitted for its cannabis-based therapy for two difficult-to-treat epilepsies that appear in childhood.

U.S. regulators” decision to review the application on an accelerated timetable follows GW’s submission  of a Marketing Authorization Application to the European Medicines Agency in December 2017.

Both cover Epidiolex (cannabidiol) as an add-on treatment for seizures in children with the epilepsies known as Dravet syndrome and Lennox-Gastaut syndrome, or LGS.

Dravet patients have no FDA-approved treatment for controlling seizures that can affect them throughout their lifetime.

The FDA’s decision to give Epidiolex a priority review means it is expected to decide by no later than June 27 whether to approve the treatment.

Epidiolex is GW’s lead cannabinoid therapy. The name for this type of treatment comes from the most abundant chemical component in the cannabis plant.

GW said Epidiolex works by mimicking the natural cannabinoids that act on our endocannabinoid system — a collection of receptors, mainly in the brain, that are configured only to accept cannabinoids.

In epilepsy, the endocannabinoid system is defective — and one result is seizures.

Cannabidiol, the most abundant nonpsychoactive cannabinoid, has shown anti-seizure characteristics in both lab and animal models of epilepsy. There are also indications that it has antioxidant and anti-inflammatory properties.

The compound’s lack of psychoactive effects, and the preclinical-trial evidence that it has anti-seizure properties, have generated interest in it as a potential anti-seizure drug in humans.

GW used the results of four Phase 3 pivotal clinical trials to support both its New Drug Application and Marketing Authorization Application for Epidiolex. Two of the trials dealt with it as a possible treatment for Dravet syndrome and two for LGS. The trials also looked at Epidiolex as potential treatments for  Tuberous Sclerosis Complex and Infantile Spasms.

The first Phase 3 trial (NCT02091375) of Epidiolex in Dravet syndrome involved 120 patients aged 6 to 10 years old. Sixty-one were randomly assigned to Epidiolex and 59 to a placebo. Each group also received standard epilepsy treatment.

The trial’s primary objective was to see whether Epidiolex could lower the number of patients’ monthly convulsive seizures, compared with a placebo. The treatment lasted 14 weeks.

While the seizure rate in the control group dropped 13 percent, those treated with Epidiolex had a statistically significant reduction of 39 percent, results showed.

The difference between Epidiolex and the placebo’s effect on seizures surfaced during the first month and held during the treatment period.

Epidiolex was generally well tolerated. The most common adverse events, which were of mild or moderate intensity, included difficulty sleeping, diarrhea and decreased appetite.

GW Pharmaceuticals is recruiting participants for another Phase 3 trial (NCT02224703) of Epidiolex in Dravet syndrome. The goal is to evaluate Epidiolex’s potential anti-seizure effects in 150 children and adults. Two groups of participants will receive either a low or high dose of the treatment, with the high dose twice that of the low dose. Two other groups will receive either high or low doses of a placebo.

Once again the primary objective is to see whether Epidiolex can reduce the number of patients’ seizures, compared with a placebo, during 14 weeks of treatment.

The FDA has given Epidiolex a Fast Track Designation as a potential Dravet syndrome treatment, and the European Medicines Agency has given it an orphan medicine designation, which is aimed at accelerating approval of treatments for rare diseases.

“We are pleased with the FDA’s acceptance of our NDA [New Drug Application] filing with Priority Review, an action that underscores the unmet need in the LGS and Dravet syndrome populations,” Justin Gover, GW’s chief executive officer, said in a press release.

“We look forward to working with the FDA during the review process to support the case for approval of Epidiolex so as to provide a much-needed new treatment option for patients that suffer from these highly treatment-resistant conditions of childhood-onset epilepsy,” he added.