HOUSTON—Pharmaceutical-grade cannabidiol (CBD) may reduce seizure severity in adults and children with medically refractory epilepsy, according to an open-label trial described at the 70th Annual Meeting of the American Epilepsy Society. A controlled trial to confirm the drug’s effect may be warranted.
Jennifer L. DeWolfe, DO, Associate Professor of Neurology at the University of Alabama at Birmingham, and colleagues conducted a state-sponsored compassionate-use study of CBD in patients with refractory epilepsy. Patients received Epidiolex (a CBD formulation developed by GW Pharmaceuticals) in addition to their antiepileptic drugs. Eligible participants were adults and children with epilepsy confirmed by video EEG. Participants were required to have failed four antiepileptic drugs and had to have had four countable seizures per month. Exclusion criteria included psychogenic nonepileptic seizures confirmed by video EEG and prior CBD use.
Jennifer L. DeWolfe, DO
Measuring Seizure Severity Over Time
The investigators measured participants’ seizure frequency and used the Chalfont Seizure Severity Scale to measure seizure severity. The scale solicits information about various factors, such as whether the patient lost awareness, dropped an object, fell, or was injured. The total possible score on the scale is 178, and the score increases with seizure severity. Changes of 10 or more points were considered significant. The researchers particularly focused on participants’ most frequent seizure type, which the Chalfont Seizure Severity Scale names the Type 1 seizure.
Dr. DeWolfe and colleagues measured patients’ total seizure severity scores and severity scores for Type 1 seizures at baseline, three months, and six months. To compare the scores, the researchers calculated time-weighted average values. They also examined percent change in seizures; seizure severity in adults, children, and all patients; and severity in responders and nonresponders. Responders were defined as patients who had a reduction in seizure frequency of more than 50%. The analysis included 81 participants, approximately half of whom were children. At the time of the analysis, 57 patients had undergone evaluation at three months, and 47 patients had undergone evaluation at six months. At baseline, the majority of patients had at least two types of seizures.
Seizure Severity Was Reduced
The total change in Chalfont Seizure Severity Scale score at three months was significant for adults, children, and all patients. The change remained significant at six months. The difference in the percent change in seizure severity between responders and nonresponders was significant at three months, but not at six months.
The change in severity of Type 1 seizures was significant for adults, children, and all patients at three months and at six months. The difference between responders and nonresponders in change in severity of Type 1 seizures was significant at three months, but not at six months.
At three months, the majority of adults, the majority of all patients, the majority of responders, and the majority of nonresponders had a reduction in seizure severity of at least 10 points. Approximately one-third of children had a reduction in seizure severity of at least 10 points at three months. At six months, the majority of adults, children, all patients, responders, and nonresponders had a decrease in seizure severity of at least 10 points. Patients’ average seizure severity tended to increase at six months, compared with the three-month point, but was still significantly lower than at baseline.
“One of the things I find most exciting is [that] … even if you were considered a nonresponder, you still had improvement in seizure severity,” said Dr. DeWolfe. She and her colleagues plan to examine the data by seizure type (eg, absence or tonic-clonic), to identify which factors measured by the Chalfont Seizure Severity Scale contributed most to the reductions in seizure severity, and to examine whether the effect of CBD on levels of antiepileptic drugs contributed to the change in seizure severity. The findings of this open-label trial suggest that CBD may improve seizure severity in people with medically refractory epilepsy. Randomized placebo-controlled studies are needed to further evaluate the effects of CBD on seizure severity.
—Erik Greb
Suggested Reading
Devinsky O, Marsh E, Friedman D, et al. Cannabidiol in patients with treatment-resistant epilepsy: an open-label interventional trial. Lancet Neurol. 2016;15(3):270-278.
Porter BE, Jacobson C. Report of a parent survey of cannabidiol-enriched cannabis use in pediatric treatment-resistant epilepsy. Epilepsy Behav. 2013;29(3):574-577.
