Tuesday, November 27, 2007

New Published Study Shows Sativex® Successfully Treats Neuropathic Pain


Porton Down, UK, 12 November 2007 - GW Pharmaceuticals plc (AIM: GWP) today announces that The International Association of the Study of Pain has published online the results of a study in its official journal Pain, showing that Sativex® successfully treats peripheral neuropathic pain1.

The trial was a multi centre, double-blind, randomised, placebo-controlled parallel group study, conducted in 125 patients with peripheral neuropathic pain characterised by allodynia. The publication of these data follows the previous announcement of preliminary results of this study.

In the study, Sativex demonstrated significant superiority to placebo in reducing pain, as measured on a 0-10 Numeric Rating Scale (p=0.004), the primary endpoint of the study. Statistically significant improvements were also seen in the Neuropathic Pain Scale composite score (p=0.007), sleep disturbance (p=0.001), dynamic allodynia (p=0.042), punctate allodynia (p=0.021), Pain Disability Index (p=0.003) and Patients Global Impression of Change (p<0.0001).

Sativex was well-tolerated in this study, with the majority of adverse events being mild or moderate. There were no treatment-related serious adverse events.

The five week trial was conducted in patients who were experiencing significant levels of neuropathic pain and who had failed to gain adequate relief from currently available analgesic medications. Patients enrolled in the study continued to take their existing medication throughout the trial. Sixty-nine percent of patients were taking opioid analgesics. Hence, improvements obtained on Sativex were over and above those obtained on currently available treatments.

Professor Turo Nurmikko, Principal Investigator, Professor of Pain Science and Consultant Pain Physician at the Walton Centre for Neurology and Neurosurgery, Liverpool, commented, "Peripheral neuropathic pain can be extremely disabling and is one of the most difficult types of chronic pain to treat. This study demonstrates that Sativex is effective in the relief of peripheral neuropathic pain. In particular, considering the refractory nature of their pain and that patients remained on their existing analgesia, the improvements seen on Sativex are very encouraging."

Dr Stephen Wright, Director of Research & Development at GW, noted "We are pleased that this important study has been published in Pain, a highly regarded and influential journal. This recognition of the high quality of GW clinical research and of the importance of these findings provides further evidence of the utility of Sativex in the relief of neuropathic pain, an area of significant unmet medical need."

This study is part of a broad programme of clinical trials aimed at securing future regulatory approval for Sativex in neuropathic pain. It is intended to conduct further Phase III clinical trials targeted at neuropathic pain following initial regulatory approval for Sativex in Multiple Sclerosis in Europe.

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GW Pharmaceuticals plc Today: +44 (0)20 7831 3113
Dr Geoffrey Guy, Executive Chairman
Justin Gover, Managing Director
Dr Stephen Wright, R&D Director

Financial Dynamics Tel: +44 (0)20 7831 3113
David Yates, Ben Atwell
Notes to Editors

Sativex (THC:CBD), an endocannabinoid system modulator, is derived from whole plant extracts of two specifically bred cannabis plant varieties. The extracts are combined to produce a standardised formulation containing two major components of cannabis, the cannabinoids D9-tetrahydrocannabinol(THC) and cannabidiol(CBD).

Sativex is formulated into a pump action oromucosal (mouth) spray designed for self-administration by the patient. This formulation allows for flexible dosing, ideal for the variable nature of MS. Each spray of Sativex delivers a fixed dose of 2.7mg THC and 2.5mg CBD. Sativex was generally well tolerated in the study.

Allodynia is the occurrence of pain in response to a normally non-painful stimulus (e.g. clothes touching against the skin). It is often intense and can occur in patients suffering from a range of conditions that damage the peripheral nerves (e.g. diabetes, post-herpetic neuralgia) and is a highly reliable marker of neuropathic pain. Neuropathic pain can be difficult to diagnose and may be confused with nociceptive pain (caused by bodily injury - 'visceral' or 'somatic'). The presence of allodynia can confirm that the pain experienced by the patient is truly neuropathic.

Neuropathic Pain
Neuropathic pain is caused by damage to or dysfunction of the nervous system. It is usually chronic and accompanied by unpleasant burning or shooting sensations, or extreme sensitivity to touch. The classification of central or peripheral neuropathic pain is determined by the location of the damage or dysfunction in the nervous system.
It is estimated that at least 1 per cent. of the world's population suffers from neuropathic pain, including over 600,000 patients in UK.
Neuropathic pain can be associated with many conditions including multiple sclerosis, stroke, cancer, spinal cord injury, physical trauma and peripheral neuropathy resulting from diabetes. It can also occur in patients who have previously suffered from shingles, a condition known as post-herpetic neuralgia.
Neuropathic pain is one of the most difficult types of chronic pain to treat. Since treatment options are limited, doctors often prescribe a combination of therapies in an attempt to relieve symptoms.

GW Pharmaceuticals plc
GW was founded in 1998 and listed on the AIM, a market of the London Stock Exchange, in June 2001. Operating under license from the UK Home Office, the company researches and develops cannabinoid pharmaceutical products that alleviate pain and other neurological symptoms in patients who suffer from serious ailments.

GW has assembled a team of over 100 scientists with extensive experience in developing both plant-based prescription pharmaceutical products and medicines containing controlled substances. GW occupies a world leading position in cannabinoids and has developed an extensive international network of the most prominent scientists in the field. For further information, please visit www.gwpharm.com


1. Nurmikko T, Serpell M, et al. Sativex Successfully Treats Neuropathic Pain Characterised by Allodynia: a Randomised, Double-Blind, Placebo-Controlled Trial. Pain. 2007: doi:10.1016/j.pain.2007.08.028M