|Public Limited Company|
|Traded as||NASDAQ: GWPH
|Founder||Geoffrey Guy and Brian Whittle|
|Headquarters||Porton Down Science Park, United Kingdom|
|Revenue||$33.8 million (2001)|
GW Pharmaceuticals is a British biopharmaceutical company known for its multiple sclerosis treatment product Sativex, nabiximols (brand name, Sativex). Sativex is the first natural cannabis plant derivative to gain market approval in any country. Another cannabis-based product, Epidiolex, for treatment of epilepsy, underwent phase 3 clinical trials in 2015.
Doctors Geoffrey Guy and Brian Whittle founded GW Pharmaceuticals in 1998. That year they obtained a cultivation license from the United Kingdom Home Office and the MHRA, allowing GW Pharmaceuticals to cultivate cannabis from seeds and clones to conduct scientific research concerning the medicinal uses of the plant.
In July 1998, GW Pharmaceuticals collaborated with HortaPharm B.V., a cannabis research and development business based in the Netherlands, founded by two expert horticulturists from California, Robert Connell Clarke and David Paul Watson, also known as 'Sam the Skunkman'.  HortaPharm grew medicinal strains for the Dutch government.  
Nabiximols (trade name Sativex) is a botanical drug that is a cannabis extract, administered as a mouth spray; it was approved in the UK in 2010 as a treatment for multiple sclerosis (MS) patients to alleviate neuropathic pain, spasticity, overactive bladder, and other symptoms.
Products in development
In 2015 GW Pharmaceutical initiated Phase 3 clinical trials of an investigational cannabidiol, Epidiolex, for treatment of two orphan conditions in children – Dravet and Lennox-Gastaut syndromes. GW also received fast track designation from the US FDA for use of the drug candidate to treat newborns with epilepsy.
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- Cannabis in Medical Practice: A Legal, Historical, and Pharmacological Overview of the Therapeutic Use of Marijuana (Google eBook). Books.google.ca.
- "The Inheritance of Chemical Phenotype in Cannabis sativa L.(HortaPharm B.V., 1075 VS, Amsterdam, The Netherlands and Instituto Sperimentale per le Colture Industriali, 40128 Bologna, Italy)" (PDF). Genetics.org. 1 January 2003.
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- "Seeds from the marijuana cultivar Skunk no. 1 were provided by HortaPharm BV (Amsterdam, The Netherlands) and imported under a US Drug Enforcement Administration (DEA) permit to a registered controlled substance research facility." (PDF).
- "Details released of collaboration between GW Pharmaceuticals and HortaPharm medicinal cannabis". Gwpharm.com.
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- "GWPharma – GW and Bayer Announce Marketing Agreement on Pioneering New Cannabis-based Treatment". Gwpharm.com. 30 September 2004.
- "Medical Cannabis Strains – Geoffrey Guy, MD (GW Pharmaceuticals, UK (Conference)". Youtube.com. 23 February 2010.
- Butticè, Claudio (December 9, 2015). "Therapeutic Cannabis for children – a possible new treatment for epilepsy". Meds News. Retrieved February 3, 2016.
- Tony Quested for Business Weekly. August 6, 2015 FDA backs cannabis-based medicine for in-danger newborns