- Food and Drug Administration staff wrote in briefing documents released ahead of an April 19 Advisory Committee meeting that there was "substantial evidence" of efficacy of GW Pharmaceuticals plc's Epidiolex as an adjunctive therapy to treat seizures associated with Lennox-Gastaut syndrome and Dravet syndrome in patients two years of age and older.
- The documents also said the risks, including potential liver toxicity, appeared manageable. As for efficacy, a greater median reduction in total seizure frequency was seen in the treated group (approximately 44%) than in the placebo group (approximately 24%).
- An FDA advisory panel will weigh the recommendations and evidence and make an official recommendation to the agency, but the FDA staff assessment bodes well for a potential approval this summer.
FDA staff were generally positive in reviewing the data submitted on Epidiolex (cannabidiol or CBD) in documents released prior to an FDA advisory panel committee meeting scheduled to occur Thursday. Outside experts will make a formal recommendation to the agency on approval, which the agency is not obliged to take but normally does.
The agency staff assessment concluded that Epidiolex's anticonvulsant benefit was supported by the data. The NDA submission was largely based on data from three Phase 3 clinical trials. "The applicant has provided positive results from three randomized, double-blind, placebo-controlled trials conducted in patients with LGS and DS," wrote FDA staff.
While there are currently no drugs approved for seizures in DS, LGS can be treated with medications including clobazam, rufinamide and topiramate, among others.
And because no FDA-approved drugs contain CBD, it is considered a new molecular entity for "regulatory purposes," noted the briefing.
Panel advisers concluded that the results from GW's three studies "provide substantial evidence of the effectiveness of CBD for the treatment of seizures associated with LGS and DS," and the risks associated with CBD "appeared to be acceptable."
The agency said the most prominent risk of cannabidiol — some evidence of drug-induced liver injury — was borne out in clinical trials and expanded access programs. But this risk was manageable, according to the advisers, and could be addressed through use of the appropriate language in labeling, education of prescribers about the importance of monitoring of liver enzyme levels, and risk follow-up by way of post-marketing activities.
GW also submitted data to FDA to help assess the abuse potential of cannabidiol, a Schedule 1 drug — and CBD's abuse potential was determined to be negligible.
According to analysts from Cowen, this determination "should aid CBD in being efficiently rescheduled by the DEA [Drug Enforcement Agency] following FDA approval." They also predicted "wide adoption" of the drug.
Yet, in some of the human abuse potential trials, participants did report feelings of euphoria after administration with CBD. But authors of the briefing documents chalked that up to a residual amount of dronabinol present in the 4500 mg dose of CBD that could be responsible for those feelings, suggesting abuse potential will be scrutinized closely.
The market reacted accordingly to the news; the stock price for GW rose 11% from market close on April 16 to close on April 17 after the briefing documents were made public.
GW appears to be preparing for an approval for CBD — on March 15, the company announced it had secured allowance for five new patent applications covering Epidiolex.