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Study: Cannabis Constituent Has No Effect on MS Progression
The first large non-commercial clinical study to investigate whether the main active constituent of cannabis (tetrahydrocannabinol [THC]) is effective in slowing the course of progressive multiple sclerosis (MS) has shown that there is no evidence to suggest this, although benefits were noted for patients at the lower end of the disability scale. The new study was conducted at Plymouth University in the U.K. and was published in Lancet Neurology.
The CUPID (Cannabinoid Use in Progressive Inflammatory Brain Disease) trial enrolled approximately 500 subjects with progressive MS and took 8 years to complete. The subjects were randomly assigned to receive either THC capsules or placebo capsules for 3 years, and were followed to see how their MS changed during this period. The two main outcomes of the trial were the Expanded Disability Status Scale, administered by neurologists, and the Multiple Sclerosis Impact Scale 29, a patient-reported measure of the effect of MS.
Overall, the study found no evidence to support an effect of THC on MS progression in either of the two main outcomes. However, the researchers found some evidence to suggest a beneficial effect in participants who were at the lower end of the disability scale at the time of enrollment. Another finding was that, in the study population as a whole, MS progressed more slowly than expected. This makes it more challenging to find a treatment effect when the aim of the treatment is to slow progression, the researchers noted.
The progression of MS is thought to be due to the death of nerve cells, and researchers around the world are searching for treatments that may be “neuroprotective.” Laboratory experiments have suggested that certain cannabis derivatives may have this activity.
However, researcher Professor John Zajicek noted: “Overall, our research has not supported laboratory-based findings and has shown that, although there is a suggestion of benefit to those at the lower end of the disability scale when they joined CUPID, there is little evidence to suggest that THC has a long-term impact on the slowing of progressive MS.”
Source: Plymouth University; July 22, 2013.