April 10  GW Pharmaceuticals’ stock almost doubled on the news that the British government had moved its flagship product, Sativex, from Schedule 1 to Schedule 4. Sativex is a cannabis plant extract containing approximately equal amounts of THC and CBD. It is delivered by spraying under the tongue. Here’s GW’s press release:

Porton Down, UK; 10 April 2013: GW Pharmaceuticals, the biopharmaceutical company focused on discovering, developing and commercialising novel therapeutics from its proprietary cannabinoid product platform, announced that Sativex®, its treatment for spasticity in Multiple Sclerosis, has today been rescheduled in the UK from Schedule 1 under the Misuse of Drugs Act to Schedule 4, Part 1.  The move follows a recommendation to the Home Office by the Advisory Council on Misuse of Drugs (ACMD), which determined that Sativex® has a low potential for abuse and low risk of diversion.  

This new, less restrictive scheduling means that Sativex® can be prescribed in the UK with no restriction on supply, recording, storage or destruction. The change confirms the distinction between Sativex® – with its evidence of quality, safety and efficacy as recognised by the Medicines and Healthcare products Regulatory Agency (MHRA) – and crude herbal cannabis, which will remain on Schedule 1 of the Act.  

“This rescheduling is an important legal milestone for Sativex®, both in the UK and around the world. It provides a strong reference source for lawmakers and will help differentiate Sativex® and any future cannabinoid prescription medicines developed by GW from crude herbal cannabis,” stated Dr. Geoffrey Guy, GW’s Chairman. “Achieving a low restrictive scheduling for Sativex® was one of the fundamental goals that GW set out to achieve from inception and we are delighted that the extensive scientific data generated over the last decade has informed the UK government in making this important decision.”

GW stock has fallen about 12 percent since its sharp rise earlier this week.