In a unanimous vote, FDA advisory committee waves through GW Pharma's cannabinoid Epidiolex

GW Pharma's cannabis-based epilepsy treatment inched one step closer to FDA approval. In a 13-0 vote, an expert panel decided that the risk-benefit profile of Epidiolex is favorable for the treatment of seizures stemming from two rare forms of epilepsy. It is on track to become the first cannabis-based prescription med in the U.S. 

While the panel vote is not binding, the FDA generally tends to follow committee recommendations. And on Tuesday, FDA staff published a report saying that GW Pharma provided “substantial evidence” of the drug’s effectiveness in treating seizures associated with Dravet and Lennox-Gastaut syndromes, and that they supported its approval. Both syndromes tend to appear in childhood, have a higher mortality rate than other types of epilepsy and do not respond to many of the drugs typically used to treat epilepsy. While a handful of drugs are approved for Lennox-Gastaut, there is no approvrug for Dravet syndrome.

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Epidiolex is a purified form of cannabidiol, a component of cannabis that does not induce euphoric effects. How, exactly, it wards off seizures is unknown, but it does not appear to interact with cannabinoid receptors and so, isn't likely to have abuse potential.

The NDA for Epidiolex includes data from three phase 3 studies, in which the drug "added to other antiepileptic therapies significantly reduced the frequency of seizures in patients with LGS and Dravet syndrome," GW Pharma said.

While the data show that the drug could lead to liver injury, panelists were confident these issues could be managed with labeling, education and monitoring. They also cited robust efficacy data and a large sample size given the rarity of the two syndromes as reasons for their vote. 

“This is clearly a breakthrough drug for an awful disease,” said John Mendelson, M.D., a senior research scientist at Friends Research Institute who served on the panel. 

The FDA is expected to make a decision on Epidiolex by June 27. Its approval would pave the way for other companies working on cannabis-based treatments. The Drug Enforcement Administration still classifies cannabis as a Schedule I drug, deeming it has "no currently accepted medical use and a high potential for abuse." But if it clears the FDA, it will have a demonstrated medical use, necessitating reclassification for cannabidiol. 

“We are pleased by the advisory committee’s recommendation to approve the first drug ever for the treatment of Dravet syndrome,” said Epilepsy Foundation President and CEO Philip Gattone, who testified at the meeting. “Despite significant therapeutic advances in the last few years, many individuals living with epilepsy do not achieve seizure control. Epidiolex represents hope for the many individuals living with intractable seizures and rare epilepsies, who every day face incredible challenges and disabling seizures, and live with the continual risk of serious injury and death.” 

GW Pharma already markets Sativex, which contains cannabidiol and delta-9-tetrahydrocannabinol (THC), outside the U.S. for the treatment of spasticity due to multiple sclerosis. It also has candidates for glioblastoma and schizophrenia, in development, as well as one being tested in epilepsy and autism spectrum disorders. The latter, a cannabidivarin dubbed GWP42006, recently failed a midstage trial in focal seizures.