The cannabis oral spray Nabiximols has been found to ease spasticity, which is a common symptom of Multiple Sclerosis (MS). Spasticity causes increased muscle stiffness and spasms, which can be uncomfortable and make it harder to move around, significantly affecting the quality of life of people with MS. According to the results of two MS clinical trials, nabiximols helped to relieve spasticity among participants, irrespective of the evaluated outcome measures. The treatment contains cannabidiol (CBD) and delta-9 tetrahydrocannabinol (THC), the two main active compounds of the cannabis plant. While THC is associated with the high associated with cannabis use, CBD is known to possess anti-inflammatory and anxiety-reducing effects on the body.

Nabiximols Approved in Some Countries but not in the US

Nabiximols is approved to treat MS-related spasticity in many countries, including Canada and much of Europe where it is marketed under the brand name Sativex. However, the treatment is not approved for use in the US. Spasticity in which muscles become abnormally tight over time leads to stiffness and, in some cases, pain. The identification of responders to nabiximols to test in the main trial, and who experienced at least a 20% improvement in spasticity, “was done to better reflect clinical use, since patients who do not respond to nabiximols are unlikely to remain on treatment, while those that do respond could experience substantial benefits,” the researchers wrote.

Benefits More Pronounced in Legs Than Arms in Both Trials

Both trials, GWSP0604 and SAVANT, had a run-in period during which all participants took nabiximols and self-rated their spasticity on a scale from 0 to 10 on the MS Spasticity Numerical Rating Scale (NRS), in which higher numbers reflect worse spasticity. Patients whose scores improved by at least 20% were administered nabiximols in the main trial, and patients whose scores did not improve were given a placebo. The researchers used new statistical techniques to account for missing trial data and to evaluate patient-reported daily spasm counts and scores on the modified Ashworth scale (MAS), a clinician-assessed measure of spasticity. The results showed that nabiximols led to a sustained treatment effect over 12 weeks on spasticity scores and average daily muscle spasm.

According to the researchers, the findings demonstrate the positive outcome of nabiximols compared with placebo in the treatment of spasticity in MS patients and provide robust evidence of a reduction in spasticity attributable to nabiximols. The safety data from these studies were largely consistent with data from other trials of nabiximols with common side effects of the cannabis-based therapy, including dizziness, sleepiness, and fatigue.