Drug Research
Drug Discovery & Development

GW reports positive results from Phase III study of spasticity drug

PBR Staff Writer Published 16 March 2009

Regulatory application to be submitted in second quarter of 2009

UK-based GW Pharmaceuticals has announced positive preliminary results from a pivotal Phase III double-blind randomized placebo-controlled study of Sativex in patients with spasticity due to multiple sclerosis, who have achieved inadequate spasticity relief with existing therapies.

This Phase III study used an enriched design whereby 573 patients initially received Sativex for four weeks in a single blind manner (Phase A), following which Sativex responders (n=241) were randomized to continue on Sativex or switch to placebo for a further 12 weeks in a double-blinded manner (Phase B). During the randomized period, patients were not permitted to adjust their dose.

According to GW Pharmaceuticals, the prospectively defined primary efficacy endpoint of the study - the difference between the mean change in spasticity severity of Sativex vs Placebo in Phase B - was highly statistically significantly in favour of Sativex (p=0.0002). The numeric difference between the two groups as measured on a numeric rating scale was 0.84 units from a baseline of 3.89, greater than that achieved in previous studies.

The difference between Sativex and placebo was also significant for a number of secondary endpoints. Approximately 74% of Sativex patients achieved an improvement of greater than 30% in their spasticity score over the entire study versus 51% on placebo (p=0.0003), the company said.

Following these positive results, GW will submit a regulatory application in the second quarter of 2009 in the UK and, subject to discussion with Almirall, other selected European countries. Upon approval, Sativex will be marketed exclusively in the UK by Bayer HealthCare and in the rest of Europe by Almirall.

GW also signed an amendment to the Sativex licencing agreement with Almirall. This amendment provides for the potential milestone payment to be received following this study result to reach GBP8 million. This milestone will become due upon Almirall electing to include a country within their licensed territory (Europe excluding UK) as part of the forthcoming regulatory submission to the UK. This decision is expected to be made within the next month.

Stephen Wright, R&D director at GW, said: This Phase III study is a resounding success and provides further evidence that Sativex provides meaningful efficacy for people with spasticity due to multiple sclerosis. In the last six months, GW has reported three positive Sativex studies incorporating a design modified from previous studies and we are delighted that this new approach is producing such consistent positive results.