Assessing Real World Efficacy, Safety, and 18-Month Retention Rates of Cannabidiol in Individuals With Drug Resistant Epilepsies.

BACKGROUND: Highly purified Cannabidiol (CBD, epidiolex) is approved for treating Lennox-Gastaut syndrome (LGS), Dravet syndrome (DS), and tuberous sclerosis (TSC), with off-label use in drug-resistant epilepsies. The aim of this study is to evaluate efficacy, safety, and long-term retention of CBD in a large pediatric population.

METHODS: We prospectively included all consecutive patients initiating CBD for drug-resistant epilepsy at our pediatric tertiary center from 2019 to 2021. Efficacy and safety were assessed via parental questionnaires on seizure and non-seizure outcomes at 1, 2, and 6 months, comparing each item to prior clinic visits. Retention rate was evaluated at 18 months.

RESULTS: We included 103 patients (mean age 11.2 years), with 47% receiving CBD for label-approved syndromes (23 DS, 15 LGS, 10 TSC) and 53% off-label. At 1 month, 54% of caregivers reported reduced seizure frequency and duration, with a positive overall impression in 62%. By months 2-6, 48% maintained seizure improvement, alongside sustained gains in communication (60%), alertness (54%), and motor skills (44%). Retention rates were 97% at 1 month, 90% at 2 months, 82% at 6 months, 66% at 12 months, and 55% at 18 months. Off-label use (p = 0.02), male gender (p = 0.049), and older age at initiation (p = 0.03) were associated with higher retention.

CONCLUSIONS: CBD reduced seizures and improved non seizures' morbidities in drug-resistant epilepsy. Strong 18-month retention rate, including off-label use, highlights efficacy and tolerability, underscoring the need for further real-world data in various rare epilepsy syndromes beyond its market approval.