Shares in GW Pharma were given a boost after its cannabinoid Epidiolex took a giant leap towards US approval for treating seizures linked with Lennox-Gastaut (LGS) and Dravet syndromes.

According to briefing documents posted to the FDA’s website ahead of an advisory committee meeting scheduled for later today (Thursday), "the risk-benefit profile established by the data in the application appears to support approval”.

"In general, the risks associated with CBD treatment appear acceptable, particularly given the findings of clinical (effectiveness) in Lennox-Gastaut syndrome and Dravet syndrome, which are serious, debilitating and life-threatening disorders," the authors note.

As no significant safety or efficacy issues were highlighted, it looks likely at this point that the FDA’s Peripheral and Central Nervous System Drugs Advisory Committee will recommend the drug’s approval.

While the FDA is not required to follow the advice of its advisory committees it usually tends to do so, which indicates that marketing clearance for the drug seems likely. A final decision from the regulator is expected by the end of June.

Epidiolex is currently under review in both the US and the EU, the filings containing data from three Phase III trials showing that Epidiolex cut the monthly seizure rate in patients with Dravet syndrome or LGS, both rare and difficult to treat forms of childhood-onset epilepsy.

In one study, patients with LGS taking Epidiolex saw a median reduction in monthly seizures of up to 42 percent compared with a 17 percent drop for placebo.

In another involving children with Dravet syndrome, five percent became seizure free while taking the drug compared to none in the placebo arm, and patients also had a significantly greater median reduction in convulsive seizures (39 percent) compared to placebo (13 percent).

GW is reportedly working with the Drug Enforcement Administration to ensure it can legally market the cannabis-based medicine, though it contains less than less than 0.1 percent of tetrahydrocannabinol, the principal psychoactive constituent of the drug.