Cannabis treatment approved for MS

Sativex, a new drug developed as adjunctive treatment for the symptomatic relief of neuropathic pain in adults with multiple sclerosis (MS), has become the first cannabis derived drug to gain approval for the treatment of MS.

The drug, manufactured by GW Pharmaceuticals in the UK, was cleared by Health Canada under the Notice of Compliance with Conditions (NOC/c) policy; meaning that it has 'demonstrated promising benefit' and 'possesses an acceptable safety profile', although GW will be required to perform additional clinical trials over the next five years.

Bayer will market the drug, which has been turned down for approval in the UK over questions of its effectiveness, and will pay GW a £2m milestone.

Sativex is administered through a spray pump under the tongue or on the inside of the cheek, the spray formulation allowing for more flexible dosing than an oral tablet. This makes it well suited to the variable nature of neuropathic pain, which occurs in up to 86% of by MS sufferers, and is inadequately countered by many currently available treatments. The most common symptoms of this pain are freezing, cold or burning sensations, usually of the limbs, and most often of the lower extremities.

In a double-blind placebo controlled parallel group study, Sativex demonstrated significantly greater pain relief than placebo, and significantly reduced pain-related sleep disturbance. Most side-effects, which included nausea, fatigue and dizziness, were mild or moderate in severity, and were often resolved with down-titration or interruption of treatment.

There are approximately 50,000 MS sufferers in Canada, where smoked cannabis is available for medicinal use and proposals for its decriminalisation are being discussed.

Industry observers expect the drug to generate peak annual sales of £250m. On announcement of its approval, shares in GW jumped by 9.5% to close at 132.5 pence on the LSE.