Study Shows Treatment with Oral Cannabinoid Has No Effect on Disease Progression in Patients with Multiple Sclerosis

Researchers report no effect of THC on MS progression, but find evidence of some benefit for patients at the lower end of the disability scale.

The authors of “Effect of Dronabinol on Progression in Progressive Multiple Sclerosis (CUPID): A Randomised, Placebo-Controlled Trial,” published in The Lancet Neurology, recruited a cohort of adult patients with primary or secondary progressive multiple sclerosis (MS) and treated them with either oral dronabinol or placebo for 36 months to determine whether the medication has any effect on the course of progressive MS. Dronabinol (also known as Marinol) is a cannabinoid commonly used to treat nausea and vomiting caused by chemotherapy and to treat loss of appetite and weight loss in patients with AIDS.

The researchers enrolled 498 patients, with 329 receiving at least one dose of dronabinol (maximum daily dose was 28 mg, titrated against bodyweight and adverse effects) and 164 receiving at least one dose of placebo. Primary outcomes for the study were change in expanded disability status scale (EDSS) score from baseline and “change from baseline in the physical impact subscale of the 29-item multiple sclerosis impact scale (MSIS-29-PHYS).”

One hundred forty-five patients in the dronabinol group had EDSS score progression, compared with 73 in the placebo group. The authors also reported that “mean yearly change in MSIS-29-PHYS score was 0·62 points (SD 3·29) in the dronabinol group versus 1·03 points (3·74) in the placebo group.”

The authors wrote that these results “show that dronabinol has no overall effect on the progression of multiple sclerosis in the progressive phase.”

However, a news release that accompanied publication of the study results noted that “there was some evidence to suggest a beneficial effect in participants who were at the lower end of the disability scale at the time of enrolment,” but this benefit was only found in a small subset of patients.

Lead author Professor John Zajicek, Professor of Clinical Neuroscience at Plymouth University Peninsula Schools of Medicine and Dentistry, said that although there is limited evidence that “certain cannabis derivatives may be neuroprotective,” the current study does not support those findings. “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,” he said.

Zajicek also noted that research efforts to identify potentially neuroprotective agents is particularly important because “current treatments for MS are limited, either being targeted at the immune system in the early stages of the disease or aimed at easing specific symptoms such as muscle spasms, fatigue or bladder problems. At present there is no treatment available to slow MS when it becomes progressive.”