New data on GW Pharma's cannabis-based epilepsy drug stokes hopes of success

GW Pharmaceuticals' ($GWPH) in-development epilepsy drug slashed rates of seizures by more than 50% in a study, a hopeful sign for the cannabis-derived treatment as it works through Phase III.

The drug, dubbed Epidiolex, is an orally administered droplet crafted from cannabidiol, a part of the marijuana plant that doesn't induce a high. In an open-label study unveiled at this week's American Academy of Neurology meeting, GW Pharma's drug reduced the number of seizures by an average of 54% among patients with severe, treatment-resistant epilepsy, investigators said, results that sent the company's shares up more than 5%.

The study was conducted through an expanded access program, which allows drugmakers to make unapproved products available to patients who have life-threatening diseases with no therapeutic alternatives, and its results by no means stand in for placebo-controlled efficacy data. But, as GW Pharma conducts a separate late-stage program, investigators believe the open-label study points to potential success for the cannabis-based therapy.

Led by New York University's Dr. Orrin Devinsky, the study enrolled 213 people from toddlers to adults and dosed them with Epidiolex twice daily. Among the 137 patients who stayed on the drug for 12 weeks, the drug led to a 54% mean reduction in seizures, including a 53% average cut in those with Dravet syndrome and a 55% reduction in sufferers with Lennox-Gastaut syndrome.

Those last two datapoints are particularly interesting for GW Pharma, which is working on two Phase III trials studying Epidiolex in Dravet and is planning a late-stage Lennox-Gastaut study for the second quarter of this year. The drug is already enrolled in the FDA's fast-track program, guaranteeing a speedy regulatory review.

About 6% of patients in the open-label study stopped taking Epidiolex due to adverse events, investigators said, and the most common side effects were drowsiness, diarrhea and decreased appetite.

GW Pharma has crafted a pipeline based around its proprietary cannabinoid development platform, anchored by the Bayer-partnered Sativex, which is approved in Europe to treat muscle spasms in multiple sclerosis patients. In the U.S., GW is working with Otsuka Pharmaceuticals to get the spray-delivered treatment FDA-approved to treat cancer pain.

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