New US Patent Allowance for Delivery of SATIVEX

GW Pharmaceuticals Announces New US Patent Allowance for Delivery of its SATIVEX® Formulation

Porton Down, UK; 3 April 2013: GW Pharmaceuticals plc (AIM: GWP), a biopharmaceutical company focused on discovering, developing and commercializing novel therapeutics from its proprietary cannabinoid product platform, today announced that the United States Patent and Trademark Office (USPTO) has issued a Notice of Allowance for U.S. Application Serial Number 13/607,897, a patent which protects delivery of its Sativex® product formulation.

The subject patent specifically covers an improved method of sublingual delivery to a human consisting of administering an extract of cannabis in ethanol and propylene glycol. The formulation may be dispensed using an aerosol spray. A Notice of Allowance is issued after the USPTO makes a determination that a patent can be granted from an application. The issued patent from this application will provide an exclusivity period until March 2021.

This new patent is one of at least seven different patent families containing one or more pending or issued patents relating to the Sativex formulation, the extracts from which Sativex is composed, the extraction technique and the therapeutic use of Sativex. GW's granted patents and pending applications (if they were to issue) relating to Sativex would expire on various dates between 2021 and 2026, excluding possible patent term extensions. There are an additional 154 issued patents covering Sativex and GW's product pipeline outside of the US.

In the indication for the treatment of cancer pain, GW has obtained a patent in the US, entitled "Pharmaceutical Compositions for the Treatment of Pain," (Patent number 7,968,594) which expires in September 2026. Sativex is currently in Phase 3 clinical development as a potential treatment of pain in people with advanced cancer. This Phase 3 program is intended to support the submission of a New Drug Application for Sativex in cancer pain with the U.S. Food and Drug Administration and elsewhere.

"This Notice of Allowance covering the Sativex pharmaceutical formulation further strengthens the patent position for Sativex in the United States, the world's largest pharmaceutical market," stated Justin Gover, GW's Chief Executive Officer. "Sativex is not only protected by seven different patent families but its exclusivity is further enhanced by other forms of protection such as plant variety rights and proprietary know-how. We believe that this matrix of intellectual property provides GW with a unique position to benefit from the rich promise within the field of cannabinoid therapeutics."

GW's intellectual property portfolio includes multiple patent families with issued and/or pending claims directed to plants, plant extracts, extraction technology, pharmaceutical formulations, drug delivery and the therapeutic uses of cannabinoids, as well as plant variety rights, know-how and trade secrets.

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About GW Pharmaceuticals plc

Founded in 1998, GW is a biopharmaceutical company focused on discovering, developing and commercializing novel therapeutics from its proprietary cannabinoid product platform in a broad range of disease areas. GW commercialized the world's first plant-derived cannabinoid prescription drug, Sativex®, which is approved for the treatment of spasticity due to multiple sclerosis in 20 countries. Sativex is also in Phase 3 clinical development as a potential treatment of pain in people with advanced cancer. This Phase 3 program is intended to support the submission of a New Drug Application for Sativex in cancer pain with the U.S. Food and Drug Administration and in other markets around the world. GW has established a world leading position in the development of plant-derived cannabinoid therapeutics and has a deep pipeline of additional cannabinoid product candidates, including two distinct compounds, GWP42004 and GWP42003, in Phase 2 clinical development for Type 2 diabetes and ulcerative colitis, respectively, and at least two additional programs expected to enter clinical trials in the next 12 months. For further information, please visit www.gwpharm.com

Forward-looking statements

This news release may contain forward-looking statements that reflect GWs current expectations regarding future events, including development and regulatory clearance of the GW's products. Forward-looking statements involve risks and uncertainties. Actual events could differ materially from those projected herein and depend on a number of factors, including (inter alia), the success of the GW's research strategies, the applicability of the discoveries made therein, the successful and timely completion of uncertainties related to the regulatory process, and the acceptance of Sativex® and other products by consumer and medical professionals. A further list and description of risks, uncertainties and other risks associated with an investment in GW can be found in GW's filings with the U.S. Securities and Exchange Commission, including its most recent Form F-1. Existing and prospective investors are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date hereof. GW undertakes no obligation to update or revise the information contained in this press release, whether as a result of new information, future events or circumstances or otherwise.