GW Pharma's marijuana-based epilepsy drug approved in US

The FDA has approved UK-based GW Pharmaceuticals' drug for a rare form of childhood epilepsy - the first marijuana-based medicine approved in the US.

Epidiolex (cannabidiol) has been tipped as a potential blockbuster and the approval is the culmination of years of trials and development of the drug, which lacks the high associated with marijuana.

The first in a new category of anti-epileptic drugs, the FDA has granted a licence for Epidiolex, an oral solution, for seizures associated with Lennox-Gastaut Syndrome (LGS) or Dravet Syndrome in patients two years of age or older.

Epidiolex is the first prescription drug formulated from highly-purified, plant derived cannabidiol, and is expected to be available within 90 days.

FDA commissioner Scott Gottlieb said the drug was an "important medical advance" but cautioned that approval did not cover medicinal cannabis, which is legal in some US states but not in others.

But the Trump administration is rumoured to be reconsidering federal prohibition of marijuana as more and more states approve it for recreational and medicinal use.

LGA and Dravet syndrome develop in childhood and are rare, severe forms of epilepsy that are notoriously difficult to treat.

Most patients with LGS and Dravet require several drugs and are resistant to many currently approved epilepsy drugs.

The conditions affect quality of life and there are high rates of early mortality

Approval was based on three phase studies ad an open-label extension study, showing Epidiolex when added to other drugs significantly reduced the frequency of seizures in patients with LGS and Dravey syndrome.

The most common adverse reactions that occurred in Epidioex treated patients included somnolence, decreased appetite and diarrhoea.

GW is also developing Epidiolex in tuberous sclerosis, and if approved in the third indication, sales could break through the billion dollar annual sales barrier.

Elizabeth Thiele, director of the paediatric epilepsy programme at Massachusetts General Hospital, professor or neurology at Harvard Medical School and a lead investigator in the Epidiolex clinical programme, said: “LGS and Dravet syndrome are two of the most severe and difficult-to-treat forms of childhood-onset epilepsy. These children and their families face a long and challenging road and very few achieve adequate seizure control.”

“Based on numerous clinical trials, this medication may help meet the need for this specific paediatric patient population and is now the first to be approved by the FDA in Dravet syndrome.”

Takeda and Ovid Pharmaceuticals last year signed a deal to develop TAK-935, a potential rival with a different mechanism of action that could be used in LGS, Dravet and tuberous sclerosis.