At 2 hours, pain relief occurred in 48.3% of placebo treatments, 54.4% of the CBD treatments, 70.5% of the THC treatments ( P = .007 versus placebo), and 69.0% of the THC/CBD treatments ( P = .014 versus placebo). At 2 hours, pain freedom occurred in 15.5% of the placebo treatments, 24.6% of the CBD treatments, 29.5% of the THC treatments, and 36.2% of the THC/CBD treatments ( P = .010 versus placebo). At 2 hours, freedom from most bothersome symptoms (MBS) occurred in 36.2% of the placebo treatments, 43.9% of the CBD treatments, 49.2% of the THC treatments, and 62.1% of the THC/CBD treatments ( P = .004 versus placebo).
To achieve at least a 20% improvement in pain relief, compared with placebo, the number needed to treat (NNT) with THC/CBD was five. For at least a 20% improvement in pain freedom, the NNT was five, and for a 20% improvement in freedom from most bothersome symptoms, the NNT was four.
Treatment with THC was associated with the highest frequency of any adverse event (31.0%), followed by CBD and THC/CBD (19.6% each), and placebo (5.0%). At 2 hours, 18.0% of the THC treatments had an adverse event, compared with 7.0% of the CBD treatments, 6.9% of the THC/CBD treatments, and 5.2% of placebo treatments.
The number needed to treat of five for pain relief was encouraging, according to Dr. Schuster. “It’s better than some other things, but at the expense of side effects. The side effects that we see are certainly higher with cannabis than it is with other migraine treatments that patients certainly should be using beforehand. There’s also a risk of addiction, which is a concern,” said Dr. Schuster.
Useful data but questions remain
Having a clinical trial will be useful for physicians, said Ali Ezzati, MD, who attended the session. “I think it was an impressive study. Obviously, there are some challenges with cannabis studies in the medical world because of the stigma that comes with it and also the possibility of inducing addiction [and] promoting that to patients. But at the end of the day, it’s very, very common for our patients to ask us about cannabinoid use, and we really don’t have data on it. I’m glad that there are people who are running these studies so we will be able at least to answer our patients,” said Dr. Ezzati, who is an associate professor of neurology at University of California, Irvine.
Dr. Ezzati also noted that clinical trials have investigated cannabinoid use for other types of pain, such as arthritic or generalized pain. Although he said that there are some clinical similarities between other types of pain and migraine, the pathophysiology appears to be unique, which means that more work needs to be done. “It will probably take 5 or 10 years to have sufficient data to give patients a direct path for using (cannabinoids),” said Dr. Ezzati.
The study was funded by the Migraine Research Foundation. Dr. Schuster has consulted with Schedule 1 Therapeutics and Vectura Fertin. Dr. Ezzati has no relevant financial disclosures.