Real-world, long-term evaluation of the tolerability and therapy retention of Epidiolex® (cannabidiol) in patients with refractory epilepsy

Objective: Epidiolex® (CBD) is FDA-approved for seizures associated with Lennox-Gastaut syndrome (LGS), Dravet syndrome (DS), and tuberous sclerosis complex (TSC). Phase III studies suggest that certain adverse effects (AEs), possibly linked to pharmacokinetic/pharmacodynamic (PK/PD) interactions may be therapy-limiting. We sought to identify these factors that contribute to treatment success and retention of therapy.

Methods: A single-center, retrospective review of patients with refractory epilepsy taking Epidiolex® was performed. Kaplan-Meier analysis was performed to describe Epidiolex® retention, as a measure of overall effectiveness.

Results: One hundred and twelve patients were screened; 4 were excluded due to loss to follow-up or never starting Epidiolex®. Of 108 patients, mean age was 20.3 years (13.1, range 2 to 63), and 52.8% were female. Mean initial and maintenance doses were 5.3 mg/kg/day (1.3) and 15.3 mg/kg/day (5.8), respectively. At the final evaluation, 75% of patients remained on Epidiolex®. The 25th percentile for discontinuation was 19 months. 46.3% of patients experienced at least one treatment-emergent adverse effect (TEAE) with 14.5% d/c Epidiolex® due to treatment emerging adverse effects (TEAE). The most common reasons for discontinuation were lack of efficacy (37%), increased seizure activity (22%), worsened behavior (22%), and sedation (22%). One out of 27 discontinuations was due to liver function test (LFT) elevations (3.7%). At initiation, 47.2% were concurrently taking clobazam, and 39.2% of those patients had an initial clobazam dose decrease. 53% of patients were able to either discontinue or lower the dose of at least one other antiseizure medication.

Significance: Epidiolex® is generally well-tolerated and the majority continued long-term treatment. Patterns of adverse effects were similar to clinical trials, however gastrointestinal complaints, and significant LFT elevations were less common. Our data suggest most patients discontinue within the first several months of treatment and suggest that further studies designed to evaluate early identification and potential mitigation of adverse effects and including drug interactions are warranted.