GW Commences Sativex® Phase III Clinical Trial in MS Spasticity

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Dec 03, 2007

GW Pharmaceuticals plc (AIM: GWP) today announces that it has started a new Phase III trial of Sativex® in Multiple Sclerosis (MS) Spasticity. This trial is designed to resolve the outstanding issue arising from the recent European regulatory submission and to provide the basis for regulatory approval of Sativex in the indication of MS Spasticity. The study aims to report headline results towards the end of 2008.

Trial Designed to Secure European Regulatory Approval in MS Spasticity Indication

The protocol design of this study follows clear guidance provided by the regulators in both their recent regulatory assessment and additional scientific advice meetings.

The objective of the study is to satisfy the regulator’s outstanding requirement for clarification related to the magnitude of the treatment effect of Sativex in “responders” (those patients that respond to treatment). In previous MS Spasticity clinical trials, the benefit obtained by responders has to some extent been masked by looking at the mean improvement across the whole studied patient population, which comprises both responders and non-responders.

GW’s existing clinical data in MS Spasticity, analysed on a “post-hoc” basis, has shown that responders can be reliably identified after four weeks treatment and that, after 12 weeks, the difference from placebo is clinically important and highly statistically significant (p=0.015). The regulators have required that this analysis be replicated in a prospectively planned study.

The new study therefore follows an “enriched design” which first identifies responders over a four week period (Phase A), and then focuses on analysing the effect of Sativex vs placebo on those responders over a further period of 12 weeks (Phase B). The study aims to recruit a total of 244 patients into Phase B.  The primary endpoint of the study is the difference between the Sativex and placebo groups in Phase B of the study in MS Spasticity as measured on a Numeric Rating Scale. This study will include hospital centres across five European countries.

Dr Stephen Wright, R&D Director, said, “This new study is an explicit requirement of the regulatory authorities and provides a route to approval for Sativex in the relief of MS-related spasticity. This study is designed to provide compelling evidence of clinically relevant benefit for Sativex in this population of people with MS and we look forward to reporting results towards the end of 2008.”

Sativex Resubmission
There are now two potential short term opportunities to re-submit Sativex for regulatory approval in Europe. In the indication of MS Neuropathic Pain, a second pivotal Phase III trial has already completed patient recruitment and is due to report headline results in the first quarter of 2008. This could lead to a regulatory filing in this indication in the first half of 2008. In the event that GW does not submit the MS Neuropathic Pain indication, the second opportunity is to resubmit for MS Spasticity following completion of the new study which has commenced today.

In addition to the MS indications, future European regulatory submissions are planned for Sativex in cancer pain and in peripheral neuropathic pain. The cancer pain clinical development programme is being conducted in the United States and funded under the collaboration with Otsuka Pharmaceutical Co. Ltd.

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