Results of a Phase III trial have shown the ability of GW Pharmaceuticals' cannabinoid-based medicine Sativex to reduce severe spasticity associated with multiple sclerosis.

According to the data, published in the European Journal of Neurology, about half of MS patients who had failed to respond to standard therapy experienced an improvement in spasticity after taking Sativex Oromucosal Spray (delta-9-tetrahydrocannabinol and cannabidiol).

The trial hit its primary goal of demonstrating that Sativex induced a significant improvement in scores of spasticity, spasm frequency and sleep disturbance related to spasticity compared to a placebo.

Following a four-week, single-blind therapeutic trial period involving 572 patients, Sativex was shown to have reduced the mean score for spasticity, with 48% of patients achieving a clinically meaningful improvement of _20% in spasticity severity. 

Of these responders, 241 took part in a 12-week, randomised, placebo-controlled trial phase, at the end of which the number of patients reporting an improvement in spasticity scores of _30% was significantly greater in the Sativex group (74%) than in the control arm (51%).

"We have been aware for a long time that cannabinoid medicines can significantly improve spasticity, which is a common, complex symptom of MS, and now the results from this study prove the positive impact they can have on patients’ symptoms, and ultimately their lives," said Professor John Zajicek, Honorary Consultant in Neurology, Derriford Hospital and Chair of Clinical Neurosciences at PCMD, University of Plymouth, commenting on the findings.

MS affects around 100,000 people in the UK, and spasticity is a common symptom that is considered to be a major cause of disability, interfering with many every day activities such as walking, picking up objects, washing or dressing.

Sativex was approved by health regulators in the UK and Spain last year, but only in patients who have not responded to other medication and who show a clinically significant improvement in symptoms during a trial run of therapy.