UK drugmaker GW Pharmaceuticals saw its stock given a boost earlier this week after it unveiled encouraging results from a small trial of its cannabis-based drug Sativex in MS spasticity.

In the ‘withdrawal’ study, 36 multiple sclerosis patients with spasticity – which is characterised by stiffness and a wide range of involuntary muscle spasms - who had been taking Sativex long-term were randomised to receive either Sativex or a ghost pill for four weeks, in order to assess whether the drug continues to provide a benefit over placebo.

The study met its primary endpoint showing that patients’ spasticity worsened when they switched from Sativex therapy to placebo, therefore providing solid evidence of long-term efficacy. Furthermore, the trial found no evidence of withdrawal syndrome in patients who stopped treatment with Sativex, “despite a very prolonged period on the medicine,” the company said.

Shareholders were pleased with the news as the data will help to strengthen Sativex’ regulatory submission in Europe, which, GW says, is now planned for the second quarter. The company was originally forced to withdraw its European submission for MS spasticity back in 2007, after it became clear that one outstanding issue required "the generation of additional data”.

Short-term data
So all eyes will now be on the larger Phase III trial testing the drug’s short-term efficacy for MS spasticity, from which results are expected at the end of this quarter. If findings are positive and the company files its submission as planned, Sativex could well be on track to finally hit the market before the end of the year.

Last year the drug’s progress in another indication, neuropathic pain associated with MS, suffered a setback after a 339-patient Phase III study reported disappointing results. Although 50% of patients receiving Sativex experienced a pain reduction of at least 30%, the trial narrowly failed to reach statistical significance due to an unexpectedly large placebo response.