GW Pharma has bagged a landmark approval for its cannabinoid Epidyolex, with European regulators clearing its use for the treatment of seizures in patients with two rare, severe forms of childhood-onset epilepsy.

Epidyolex is an oral solution of cannabidiol, which comes from the cannabis plant but lacks the ‘high’ associated with its recreational use.

The European Commission approved the drug’s use as adjunctive therapy of seizures associated with Lennox Gastaut syndrome (LGS) or Dravet syndrome, in conjunction with clobazam, for patients two years of age and older, paving the way for its launch across Europe.

More than 90% of patients with LGS or Dravet syndrome have multiple seizures per day, which puts them at constant risk for falls and injury.

The drug’s clearance rides on the back of results from four randomised, controlled Phase III trials, incorporating data from more than 714 patients with either condition, both of which remain highly treatment-resistant despite currently available therapies.

When added to other antiepileptic therapies, Epidyolex “significantly reduced the frequency of seizures in patients,” according to GW Pharma.

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

In another involving children with Dravet syndrome, 5% 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%) compared to placebo (13%).

“The approval of Epidyolex marks a significant milestone, offering patients and their families the first in a new class of epilepsy medicines and the first and only EMA-approved CBD medicine to treat two severe and life-threatening forms of childhood-onset epilepsy,” said Justin Gover, GW’s chief executive.

“This approval is the culmination of many years of dedication and collaboration between GW, physicians and the epilepsy community. We believe patients and physicians deserve access to rigorously tested and evaluated cannabis-based medicines, manufactured to the highest standards and approved by medicines regulators, and we are delighted to be the first to offer this solution to the epilepsy community.”

A ‘medical minefield’?

However, while noting that Epidyolex will “bring hope for some families” and that the approval “feels like a positive step”, Ley Sander, medical director at the Epilepsy Society and Professor of Neurology at University College London, said medicinal cannabis “still remains a medical minefield and there are many hurdles ahead”.

“CBD was not recommended by NICE for prescription on the NHS. It is important that the pharmaceutical industry continues to work with the medical advisory body to ensure that drugs are cost effective and that its long-term effects are clear,” he stressed.

NICE rejection NHS funding for the drug just weeks ago, after its appraisal committee noted that despite clinical trial evidence a reduction in the number of the main types of seizures associated with epilepsy, the duration of the studies was only 14 weeks, and so the longer-term effectiveness of the treatment is still uncertain.

Concerns about the economic models provided by the company were also cited. Importantly, the committee felt that the models may not capture all aspects of severe treatment-resistant epilepsy that are important to people with these conditions, and to their carers and families.

The Institute did highlight, however, its commitment to working with the company to resolve the economic modelling issues identified by the committee, and to help GW understand what it may need to do to mitigate the cost of cannabidiol to the NHS.