Abstracts

Rationale: Epidiolex is being investigated for its utility in treating patients with treatment-resistant epilepsy. While studies suggest an overall positive impact on seizure control, little is known regarding the impact of CBD on EEG. The goal of this study is to determine the effect of pharmaceutical grade Cannabidiol (CBD) formulation (Epidiolex) on the EEG of children and adults participating in a state-sponsored, open-label compassionate use study. Patients with video-EEG confirmed treatment-refractory epilepsy who have failed at least 4 different AEDS and with on average at least 4 countable seizures per month are included. Methods: All patients in the UAB CBD Program received routine, at least 20-minute long, EEG prior to starting CBD. CBD was initiated at 5mg/kg/day and titrated upwards for optimal seizure control every 2 weeks by 5mg/kg/day. Repeat EEG was obtained at 2 weeks following stable dose of 25 mg/kg/day (approximately 12 weeks into the study). Titration of CBD was continued in selected patients up to the maximum dose of 50 mg/kg/day. Of the 81 participants, 55 (27 adult and 28 children) completed the on-CBD EEG. Pre-/on-CBD EEGs were independently reviewed by two investigators. Reviews were compared and discrepancies mediated. Data were analyzed for the following criteria: background frequency, focal slowing, reactivity, frequency of interictal epileptiform discharges (IED), and total number of seizures. For comparison, each patient served as his/her own control. Responder status at the time of repeat EEG was not yet established, therefore EEG changes between responders and non-responders was not included in the analysis. Background frequency, IED averaged over the duration time, and total number of seizures were analyzed by Paired t-test and Wilcoxon signed rank sum test. Focal slowing and reactivity were analyzed by Chi-square test. An alpha level of 0.05 was used as cutoff for statistical significance. Results: Paired t-test demonstrated that the patients' IED averaged over the EEG duration were significantly decreased after initiation and maintenance of CBD (M=3.1, SD= 9.9, p= 0.02). This result was led by the pediatric arm (M=6.0; SD=13.3; p=0.02) with the adult arm showing less pronounced and non-significant improvement in average IED when considered independently (M=0.29, SD=2.8 p=0.59). There was no significant change in background frequency (M=0.10; SD =0.79; p=0.35), total number of seizures (M=0.67; SD= 2.9; p= 0.09), or focal slowing (p=0.68). Reactivity was present in all studies prior to and on CBD. Conclusions: In this study, CBD decreases the frequency of IEDs in a cohort of patients with difficult to control epilepsies, particularly in pediatric patients. There was no impact on seizure number, background frequency, focal slowing or reactivity. Funding: General funds, state of Alabama