GW Pharmaceuticals and its US subsidiary Greenwich Biosciences have announced the successful treatment of seizures in patients suffering from tuberous sclerosis complex (TSC), a rare form of childhood epilepsy, using Epidiolex oral solution during a late-stage trial.
GW Pharmaceuticals is involved in the development and commercialisation of cannabinoid prescription medicines.
The companies claimed that they achieved positive top-line results from a randomised, double-blind, placebo-controlled Phase III clinical trial of Epidiolex (cannabidiol or CBD) CV.
Epidiolex is the first cannabis-based medicine to secure approval from the US regulators in June, when they allowed the treatment for two other forms of childhood epilepsy.
During the trial, two doses of Epidiolex, 25mg/kg/day and 50mg/kg/day, were tested against a placebo in treatment-resistant TSC patients aged between one and 65.
The company said that Epidiolex met its primary endpoint, which was the reduction in seizure frequency compared to baseline of the Epidiolex 25mg/kg/day dose group versus placebo.
It said that the doses reduced seizures by 47.5% and 48.6%, compared with a 26.5% reduction in patients taking a placebo.
Furthermore, the safety profile was consistent with findings from previous studies, with no new safety risks, and secondary endpoints were supportive of the effects on the primary endpoint.
Three teams comprising 224 patients were involved in the 16-week trial, where Epidiolex 25mg/kg/day, Epidiolex 50mg/kg/day or placebo (n=76) was added to anti-epileptic drug (AED) treatment.
The company intends to focus on the 25mg/kg/day dose due to its fewer side-effects.
The trial was carried out at more than 40 clinical sites in over six countries.
GW Pharmaceuticals plans to file for US approval in the fourth quarter of this year.
The company has submitted a Marketing Authorisation Application (MAA) to the European Medicines Agency (EMA) for Epidyolex (European brand name) and expects the agency’s opinion in the second quarter of 2019.
GW chief medical officer Dr Volker Knappertz said: “We are delighted to report this positive trial in patients with TSC. Both doses studied in this trial have been shown to be equally effective.
“There is a lower incidence of known adverse events and laboratory changes in the 25mg/kg/day group compared with 50mg/kg/day.
“As a result, we expect to focus our label expansion discussions with the FDA on the lower dose, which is close to the dose range already included in the US prescribing information.”