GW Pharmaceuticals of the UK has been boosted by the publication of data which shows that the firm’s cannabis-derived drug Sativex successfully treats peripheral neuropathic pain.

The data, published by the International Association of the Study of Pain, comes from a five-week, double-blind, randomised, placebo-controlled parallel group study, conducted in 125 patients with peripheral neuropathic pain characterised by allodynia who had failed to gain adequate relief from currently available analgesics. In the study, Sativex (delta-9-tetrahydrocannabinol and cannabidiol) demonstrated significant superiority to placebo in reducing pain, and statistically significant improvements were also seen in sleep disturbance.

Sativex was well-tolerated in this study, with the majority of adverse events being mild or moderate and Turo Nurmikko, principal investigator and a professor at the Walton Centre for Neurology and Neurosurgery in Liverpool, said the data is impressive given that it “is one of the most difficult types of chronic pain to treat”. He added that “considering the refractory nature of their pain and that patients remained on their existing analgesia, the improvements seen on Sativex are very encouraging."

Stephen Wright, the firm’s director of R&D, said the publication of the study is “recognition of the high quality of GW clinical research and of the importance of these findings provides further evidence of the utility of Sativex".

Further Phase III clinical trials targeted at neuropathic pain will take place but GW’s initial focus is to get regulatory approval in Europe for Sativex to treat spasticity in multiple sclerosis. In July, the company withdraw its regulatory dossier for Sativex after what it termed “constructive and detailed discussions with regulatory authorities” in Europe. It now plans to re-file in 2008 after being provided with a “clear path to approval” in MS.

Canada gave the regulatory green light to Sativex for the relief of neuropathic pain in adult MS patients as long ago as April 2005 and this summer it was approved there as a treatment for cancer pain.