GW Pharmaceuticals has started a second Phase III trial of its cannabis-based pharmaceutical Sativex in patients with multiple sclerosis who suffer neuropathic pain but cannot find relief with current therapies.

An earlier Phase III study in the same patient population found that Sativex was significantly better than placebo at alleviating both pain and the sleep disturbances that can occur as a result.

Usually two pivotal studies are required to secure regulatory approval for new products, so once the new study is concluded GW will be able to press ahead with a filing for MS-related neuropathic pain in Europe. In addition, data from the two studies will be used to complement data from two other ongoing studies in peripheral neuropathy, which could corm the basis of a broad indication for general neuropathic pain.

Sativex is already approved in Canada as adjunctive treatment for the symptomatic relief of neuropathic pain in MS, but on condition that the new study supports its safety and efficacy in this indication. Canada was the first country in the world to approve Sativex.