Provides Further Evidence of Long-term Efficacy

LONDON, UK I August 5, 2013 I GW Pharmaceuticals plc (NASDAQ: GWPH, AIM: GWP, “GW,” “the Company” or “the Group”), a biopharmaceutical company focused on discovering, developing and commercializing novel therapeutics from its proprietary cannabinoid product platform, announces top-line results from a 12 month placebo-controlled study of Sativex in patients with spasticity due to Multiple Sclerosis (MS). The study results confirm the reassuring safety profile of Sativex and provide further evidence of long-term efficacy.

The study was a 12 month multicentre, double-blind, randomised parallel group, placebo-controlled study in 121 patients with MS spasticity. The study was required as a post-approval commitment by the UK regulatory authority, the Medicines and Healthcare products Regulatory agency (MHRA), with the primary objective of evaluating whether Sativex may have long term adverse effects on cognitive function or mood. The primary endpoint was the change in cognitive function as assessed by the total Paced Auditory Serial Addition Test (PASAT) score from baseline to end of treatment.  Mood was assessed by the Beck Depression Inventory-II.

There was a slight improvement in the PASAT score from the beginning to the end of the study in both the Sativex and placebo groups, thus confirming that there is no evidence of long-term cognitive impairment in patients taking Sativex compared with those taking placebo.  Similarly, the change in mood over the 12 month period was more or less identical in the Sativex and the placebo group, confirming no untoward effect on mood.

The key efficacy secondary endpoints were the global impression of change scores as assessed by the patient, physician and carer. Each of these endpoints was highly significantly in favour of Sativex (p

Detailed data from this study is due to be presented at the 29th Congress of the European Committee for Treatment and Research in Multiple Sclerosis (ECTRIMS) on 2-5 October in Copenhagen, Denmark.

Dr Stephen Wright, GW’s R&D Director, said, “We are pleased to report positive and wholly reassuring results from this 12 month placebo-controlled study in patients with MS spasticity. We have now shown that Sativex does not impair cognition either in short-term or in long-term use in well designed, randomised, placebo controlled clinical trials.  These data not only confirm the good tolerability of Sativex in long-term use but also provide further evidence of efficacy consistent with that seen in previous shorter duration clinical trials.”

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 22 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 Phase 1 and Phase 2 clinical trials in the next 12 months. For further information, please visit www.gwpharm.com.

SOURCE: GW Pharmaceuticals