GW Pharmaceuticals has ended the week on quite a high after the UK drugmaker unveiled positive preliminary late-stage data for its cannabis-based drug Sativex in multiple sclerosis spasticity.

The Phase III study involved 573 patients who had inadequate spasticity relief with existing MS treatments. They were given Sativex (delta-9-tetrahydrocannabinol and cannabidiol) for 4 weeks, after which responders (241 patients) were randomised to continue on the drug or switch to placebo for an additional 12 weeks.

The results showed that the difference between the mean change in spasticity severity in those who received the GW compared with placebo, was "highly statistically significantly in favour of Sativex”. Stephen Wright, GW’s R&D director said the study is “a resounding success and provides further evidence that Sativex provides meaningful efficacy for people with spasticity due to MS”.

He added that 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”. On the back of these positive results, GW will submit a regulatory application in the second quarter in the UK, where it will be marketed by Bayer.

In the rest of Europe, GW’s partner is Almirall and the Porton Down-headquartered firm noted that has amended its licensing deal with the Spanish group for the potential milestone payment to be received following this study result to reach £8 million. That is dependent on Almirall electing to include a country (probably Spain) as part of the forthcoming regulatory submission to the UK. This decision is expected to be made within the next month.

Justin Gover, GW’s managing director, said the firm has “a history of maintaining a strong financial position and this increased potential milestone payment represents an attractive opportunity to further consolidate this position”.

Analysts were impressed and Jacob Plieth at Edison Investment Research said that “the positive results have significantly strengthened the investment case for GW”. He added that the possible £8 million cash boost, in return for a reduction in later payments, will not trigger an increase in spending but “we also view strategic acquisitions of assets and/or companies as a possibility”. Mr Plieth went on to say that GW should become profitable during 2009.