The trial was a multi-center double-blind, randomized, placebo-controlled parallel group study. Patients in the study had advanced cancer and were experiencing pain that was not responding adequately to strong opioid medication such as morphine.
In addition to study medication, all patients remained on their existing opioid and other analgesic medication during the trial.
The study included two different study medications – Sativex, a cannabis medicine containing tetrahydrocannabinol (THC) and cannabidiol (CBD), and a THC-rich extract.
In the trial, Sativex achieved a statistically significant improvement in comparison to placebo in pain as measured on a numerical rating scale, a primary endpoint of the study. A responder analysis showed that approximately 40% of patients on Sativex showed a greater than 30% improvement in their pain.
Analysis of escape medication, a second primary endpoint, showed that there were no significant changes in the use of escape medication. The improvements seen in pain were therefore attributable to the positive effects of Sativex.
The other active arm of this study, GW’s THC extract, did not show a significant effect in pain. This trial therefore suggests that Sativex is the more effective product for use in cancer pain.
Dr Stephen Wright, GW’s R&D director, said, “The data from this important trial further demonstrates the broad potential of Sativex, not only in its initial multiple sclerosis and neuropathic pain markets, but also in cancer and potentially other types of chronic pain.”
Sativex is currently the subject of regulatory applications in both the UK and Canada. A qualifying notice for approval in Canada was received in December 2004 for the use of Sativex in the treatment of neuropathic pain in multiple sclerosis. In both countries, upon approval, Sativex will be exclusively marketed by Bayer HealthCare.