Phase 3, 28-week, Randomized, Double-blind, Placebo-controlled Safety and Efficacy Study of Nabiximols as an add-on Therapy in Subjects With Spasticity Due to Multiple Sclerosis.

Inclusion Criteria: * Willing and able to give written informed consent. * The subject is at least 18 years of age or older. * Diagnosed with any disease sub-type of multiple sclerosis of at least six months duration. * Spasticity due to multiple sclerosis of at least six months duration, which is not wholly relieved with current anti-spasticity therapy, and which is expected to remain stable for the duration of the study. * Subject must be receiving at least one of the following anti-spasticity therapies to be eligible: Baclofen, Tizanidine, Clonazepam, Diazepam, Dantrolene. * Subject is willing to maintain anti-spasticity medication at a stable dose for the duration of the study and should be stable for 30 days prior to screening. * If the subject is currently taking disease-modifying medication, this must be at a stable dose for at least three months prior to the screening visit; the dose must also remain stable for the duration of the study. Exclusion Criteria: * Has previously used Nabiximols or Sativex. * The subject is currently using or has used cannabis or cannabinoid based medications within 30 days of study entry and is unwilling to abstain for the duration of the study. * Any history or immediate family history of schizophrenia, other psychotic illness, severe personality disorder or other significant psychiatric disorder other than depression associated with their underlying condition. * In the opinion of the Investigator, any known or suspected history of a s…