Effectiveness of cannabidiol in a prospective cohort of children with drug-resistant epileptic encephalopathy in Argentina

Objective: We report our preliminary findings regarding effectiveness, safety, and tolerability of cannabidiol (CBD) added to antiepileptic therapy in a cohort of children with drug-resistant epileptic encephalopathies (EEs) with a mean follow-up of 8.5 months (range, 3-12 months). Methods: A prospective cohort study was designed with the aim of assessing the effectiveness, safety, and tolerability of the addition of CBD to standard antiseizure medications (ASMs) in children with drug-resistant EE enrolled at a single center (Neurology Department, Hospital de Pediatria Juan P. Garrahan, Buenos Aires, Argentina). Results: Fifty patients were enrolled between October 2018 and October 2019, 49 of whom had a follow-up of at least 3 months at the time this interim analysis was performed. Mean age at enrollment was 10.5 years (range 2-16). Median age at first seizure was 7 months. Up to the last visit of each patient (follow-up 3-12 months) 39/49 children (80 %) had responded to treatment with a decrease in seizure frequency. Overall, 77.6 % of the patients had a seizure reduction of at least 25 %, 73.5 % had a >= 50 % reduction, and 49 % had a >= 75 % reduction. Mean monthly seizure frequency was reduced from 959 to 381 (median decrease from 299 to 102, range, 38-1900; median decrease 66 %, p< 0.001). All adverse effects were mild or moderate. The most common adverse effect was drowsiness (in 32 %), usually reversed by adjusting clobazam dose (in 12 children). Conclusion: In children with drug-resistant EEs, CBD oil as an adjuvant therapy to antiepileptic therapy seems safe, well tolerated, and effective.