A Cost-Utility Analysis of Add-On Cannabidiol Versus Usual Care Alone for the Treatment of Seizures Associated with Tuberous Sclerosis Complex in England and Wales

ObjectivesThe aim of this study was to evaluate the cost effectiveness of plant-derived highly purified cannabidiol (Epidyolex (R) in the UK; 100 mg/mL oral solution) as an add-on treatment to usual care for the management of treatment-refractory seizures associated with tuberous sclerosis complex (TSC) in patients aged >= 2 years.MethodsA cohort-based model was developed using a National Health Service perspective and lifetime horizon. Health states were based on weekly seizure frequency and seizure-free days, utilizing patient-level data from the GWPCARE6 trial (ClinicalTrials.gov identifier: NCT02544763). Two independent regression models were applied to individual patient-level data to predict seizure-free days and seizure frequency. Healthcare resource utilization data were sourced from a Delphi panel, and patient and caregiver health-related quality of life values were elicited using vignettes valued by the general public. Outcomes relating to TSC-associated neuropsychiatric disorders were modeled with costs and quality-adjusted life-years sourced from published literature.ResultsIn the base case, compared with usual care alone, 12 mg/kg/day cannabidiol was associated with an incremental cost-effectiveness ratio (ICER) of 23,797 pound. The National Institute for Health and Care Excellence disease severity modifier reduced the ICER to 19,831 pound. Probabilities of cost effectiveness at willingness-to-pay thresholds of 20,000 pound and 30,000 pound were 30% and 52%, respectively, for the base case and 39% and 66%, respectively, for the disease severity modifier. Results were robust to sensitivity and scenario analyses.ConclusionsAt 12 mg/kg/day and an ICER threshold of 20,000- pound 30,000 pound, we provide evidence for the cost effectiveness of add-on cannabidiol treatment for patients with TSC-associated seizures aged >= 2 years who are refractory to current treatment.