Top-line data from the first randomized controlled trial of cannabidiol (Epidiolex) indicated the drug was better than placebo at reducing seizures among children with Dravet syndrome, according to a .
Those on the drug had a 39% reduction in seizures compared with a 13% reduction for those on placebo (P=0.01), the company said.
GW Pharmaceuticals has orphan drug and fast-track status for the Dravet indication, a rare form of epilepsy in children that currently has no approved drug treatments.
The phase III trial randomized 120 children with Dravet, mean age 10, to either Epidiolex 20 mg/kg/day or placebo. Participants had a median baseline frequency of 13 convulsive seizures per month.
Investigational treatment was added to current drug regimens, and patients were typically taking three medications, having previously failed an average of four other drugs.
The primary endpoint of seizure reduction during the 14 weeks of treatment compared with a baseline 4-week observation period showed a significantly greater decline for those on cannabidiol (39% versus 13%, P=0.01).
That difference emerged during the first month of treatment and was sustained during entire treatment period, according to the press release.
Cannabidiol was generally well tolerated, with the most common adverse events (occurring in at least 10% of patients) being somnolence, diarrhea, decreased appetite, fatigue, pyrexia, vomiting, lethargy, upper respiratory tract infection, and convulsion -- and the majority were mild to moderate, the company said.
However, greater numbers of serious adverse events occurred in those on the drug (10 versus three), and discontinuations were higher with cannabidiol (eight versus one).
In addition to this trial, GW is conducting four other randomized controlled trials of Epidiolex: another in Dravet syndrome (which will include 150 patients), two in Lennox-Gastaut syndrome, and a recently added study in tuberous sclerosis complex, another seizure disorder.
Previously, there was only open-label evidence for the drug's efficacy.
Cannabidiol is one of dozens of compounds in marijuana but has been credited with many of the herb's reputed medical benefits. It is said to be nonpsychoactive, unlike THC.
GW Pharma also sells the mixed cannabidiol-THC oral spray Sativex.