Epilepsy is a neurological disorder affecting more than 50 million people globally, including more than 260,000 Canadians. Cannabidiol (CBD) reduces seizure frequency and improves quality of life for adults and children with Drug Resistant Epilepsy (DRE). Several uncontrolled, small, open label studies reported that CBD-enriched Cannabis Herbal Extract (CHE) resulted in a reduction of seizure frequency, but we lack critical information on efficacy, comparative effectiveness and dosing of CBD and ∆9-tetrahydrocannabinol (THC) in children and adults with DRE. CAN-DRE is an early phase, triple-blind, placebo-controlled, randomized clinical trial to answer the questions of if cannabinoids work to reduce seizures in children and adults (24 months to 55 years) with DRE and if CBD works better in an isolate or in a CBD-enriched Cannabis Herbal Extract. The primary outcome of CAN-DRE is reported monthly seizure count from baseline to maintenance phase.

Inclusion Criteria:

1. Ages 24 months to 55 years old at the time of enrollment
2. Diagnosed with DRE: not achieved seizure freedom, with adequate trials of 2 antiseizure medications 29
3. Medical history of 4 + clinically recognizable seizures (any type with clusters counted as a single event) per month
4. Have a negative pregnancy test at screening for patients who have experienced menarche
5. Agree to abstain from driving and recreational cannabis use throughout the study

Exclusion Criteria:

1. Diagnosis of psychogenic non-epileptic seizure
2. Recent (<30 days) change in anticonvulsant therapies including anticonvulsant medications, or settings on vagal nerve stimulator
3. Ketogenic diet started within 6 months (participants stable on the ketogenic diet for more than 6 months are eligible to participate)
4. Vagal nerve stimulator implanted and activated within 12 months
5. Concomitant regular use of narcotics (except in emergencies and physician supervised)
6. Initiation or dosage change of oral or injected steroids within 3 months
7. Allergy or intolerance to compounds in trial preparations
8. DRE secondary to progressive neurological disease
9. Clinically significant cardiac, renal or hepatic disease (as assessed by site investigator); elevated liver enzymes (GGT and/or AST and/or ALT) or lipase >3 times upper limit, adjusted for age
10. History of psychotic disorders
11. Uncontrolled (in the perspective of the qualified investigator) medical conditions including substance use disorders
12. History or concurrent cannabis use disorder
13. Unwilling or unable to use highly effective methods of contraception throughout the study period and three months post-trial, where applicable

No, summary level data may be available from the CAN-DRE steering committee following research ethics board approval.