Cannabis-derived Dravet syndrome drug gets US orphan drug approval

Epidiolex, a medicine that uses cannabidiol (CBD) as an active ingredient, has been designated an orphan drug for Dravet syndrome by the US Food and Drug Administration, giving manufacturer GW Pharmaceuticals the go-ahead to run a clinical development programme next year.

CBD is a non-psychoactive compound derived from the cannabis plant. In GW Pharmaceuticals’ formulation, it is administered orally, as a liquid.

The orphan drug designation means it is recognised as a potential therapy for a condition that only affects a small number of people – in this case a rare form of paediatric epilepsy.

Dravet syndrome usually manifests in the first year of life of infants who are otherwise developing normally. It is characterised by both clonic and tonic-clonic seizures, intellectual disability and a relatively high risk of sudden unexpected death in epilepsy.

Around 5,440 children in the US and a further 6,710 in Europe are thought to be affected, though the actual figures may be greater as the condition is reportedly underdiagnosed.

Dravet syndrome does not respond to conventional antiepileptic drugs, though past studies have shown cannabinoid treatments to be effective in stopping a patient’s seizures.

GW Pharmaceuticals expects to begin a formal clinical development programme for Epidiolex in 2014. In the meantime, some US paediatric epilepsy specialists will be able to treat patients with the drug immediately thanks to seven Investigational New Drug (IND) applications granted to the firm by the FDA.

Around 125 children with Dravet syndrome, Lennox-Gastaut syndrome and other refractory epilepsies will benefit from these IND programmes.

Orrin Devinsky, a professor of neurology, neurosurgery and psychiatry at New York University’s Comprehensive Epilepsy Center, described the FDA’s decision as a “key milestone” following “encouraging evidence” that CBD can be used as a novel treatment for Dravet syndrome.

“With GW now making plans to advance Epidiolex through an FDA development programme, we have the prospect for the first time of fully understanding the science of CBD in epilepsy with a view to making an appropriately tested and approved prescription medicine available in the future for children who suffer from this debilitating disease,” he commented.

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