CBD Shows Benefit as Adjuvant Treatment in Adults With Drug-Resistant Focal Epilepsy

Silvia Kochen, MD, PhD

In a recently published prospective, observational study, the use of cannabidiol (CBD) as an adjuvant therapy was effective, safe, and associated with significant improvement in quality of life among adults with drug-resistant focal epilepsy. Improvements in quality of life were not all attributed to decreased seizure frequency, as some authors found it might have been explained by high tolerance.

CBD, an antiseizure medication (ASM) approved for rare epilepsies like Dravet syndrome, Lennox-Gastaut syndrome (LGS), and tuberous sclerosis complex (TSC), was assessed in a cohort of 44 adults with drug-resistant focal epilepsy who completed the 6-month trial. In total, 86% (n = 38) of the sample were considered responders, including 2 (5%) patients who were seizure-free, 14 (32%) who had seizure reductions between 80% to 99%, and 22 (50%) who were reduced between 50% and 79%.

"Our results in terms of effectiveness and seizure free are similar to those reported by other children and adolescents research groups," the study authors wrote. "According to these reports, the occurrence of seizures free percentage is similar between adults and children."

Led by Silvia Kochen, MD, PhD, research director and medical director, Neurosciences Unit, Epilepsy Center, Hospital El Cruce, the included patients were between 18 and 60 years and were not candidates for epilepsy surgery. Those with conditions such as LGS or epileptic encephalopathy, as well as status epilepticus, were excluded from the study. The mean time with epilepsy was 21 years (SD, 14), with patients on a mean of 3 (SD, 0.8) ASMs as an adjuvant treatment.

Among the 5 patients who were considered nonresponders, 1 individual presented with an increase in seizure frequency even up to a dose of 500 mg/day. The patient presented non-lesional epilepsy, with right temporal EZ defined by stereoelectroencephalography, currently treated with lamotrigine and valproic acid. Between responders and nonresponders, there were no significant differences in dose at baseline and at the end of the trial, number of seizures at baseline, time with epilepsy, age, use of vagus nerve stimulation, surgery, and MRI lesion.

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Among responding patients, the final CBD dose was a mean of 329 mg/day. Twenty patients (53%) completed the trial with a dose of 250 mg/d of CBD, 12 patients (32%) with 375 mg/d, and 6 patients (16%) with 500 mg/d. Adverse events (AEs), all mild in nature, were found in 29 patients (66%). Of those who reported AEs, 60% were gastrointestinal. Of note, 3 patients presented severe diarrhea that forced the discontinuation of CBD treatment. Another 16% and 14% of patients, respectively, reported somnolence and decreased appetite.

After 6 months of treatment, patients demonstrated significant improvement in quality of life, as assessed through the QOLIE 10 questionnaire. Specifically, 31 patients (70.4%) improved, 10 patients (22.7%) worsened, and 3 (6.8%) had no changes. Improvements were found to be independent from the decrease or worsening in the frequency of seizures.

There were no significant differences between efficacy of CBD and its relationship with seizure type, except that at the beginning of the trial, 23 patients (52%) presented focal seizures that evolved to bilateral. After 6 months of treatment with CBD, 13 patients (29%) stopped having focal seizures evolved to bilateral.

REFERENCE
1. Kochen S, Villanueva M, Bayarres L, et al. Cannabidiol as an adjuvant treatment in adults with drug-resistant focal epilepsy. Epilepsy & Behav. 2023;144:109210. doi:10.1016/j.yebeh.2023.109210