A Study to Investigate the Transition of Children From 'Artisanal" Cannabidiol (CBD) to Epidiolex

Inclusion Criteria:

• Male or female aged 2 through 18 years, inclusive.

• Clinical diagnosis of Dravet or Lennox Gastaut Syndrome:

Clinical diagnosis of Dravet Syndrome supported by:

1. Onset of seizures within the first year of life.

2. Initial seizures present as fever-induced or fever-triggered seizures, hemi-clonic,generalized tonic-clonic, prolonged seizures (more than 15 minutes).

3. Emergence of other seizure types after 1 year of age.

4. Normal development within the first year of age, then emergence ofneurodevelopmental difficulties or delay.

Clinical diagnosis of Lennox Gastaut Syndrome supported by:

a. History of an EEG with slow/disorganized background and slow (<2.5 Hz or less) spike and wave activity or generalized paroxysmal fast activity (GPFA).

b. History of more than 1 type of generalized seizures, including drop seizures (tonic, atonic or tonic-clonic).

• Participant must be willing and able to give written informed consent forparticipation. If the participant is not qualified or unable to provide writtenconsent based on age, development, intellectual capacity or other factors, theparent or legally authorized representative must provide written informed consent ontheir behalf.

• Must be on a stable dose of a licensed artisanal cannabidiol (CBD) product asmaintenance therapy for seizure control for a minimum of 3 months prior to screening (visit 1).

• 'Artisanal' CBD dose must be between 5 mg/kg/day and 20mg/kg/day.

• 'Artisanal' CBD preparation must be a high CBD to THC formulation defined as aminimum CBD:THC ratio of 20:1.

• Must be taking a minimum of 1 other anti-seizure medication (ASM) in addition to an 'artisanal' form of CBD.

• Must be on a stable dose of ASMs for a minimum of 28 days prior to screening (visit

1. and remain on a stable dose throughout the entire study unless medicallynecessary change(s) are required for safety events.

• Participants with a vagal nerve stimulator (VNS) must have the following conditionsmet:

1. The VNS has been in place for a minimum of 3 months prior to screening (visit 1).

2. The settings have remained constant for 28 days prior to screening (visit 1)and are expected to remain constant throughout the entire study.

3. The battery is expected to last for the duration of the study.

• Participants on the ketogenic diet must be on a stable regime for a minimum of 28days prior to screening (visit 1) and expected to remain stable throughout theentire study.

• Participant and/or caregiver must be willing to maintain a seizure diary throughoutthe duration of the study.

Exclusion Criteria:

• Previous or current exposure to Epidiolex.

• Supplemental use of cannabinoid-containing products, including but not limited to:

1. Recreational use of cannabis.

2. Use of artisanal CBD as a seizure rescue medication.

3. Use of more than one formulation of 'artisanal' CBD (e.g. THC supplementation).

• Pregnant or breastfeeding.

• Any clinically significant, unstable medical condition other than epilepsy that, inthe opinion of the investigator, could place the participant at increased risk orinterfere with the results of the study.

• Hepatic impairment at screening (visit 1) defined as either of the followingconditions:

1. ALT or AST > 5x upper limit of normal (ULN).

2. ALT or AST > 3x ULN and total bilirubin >2x ULN (or international normalizedratio >1.5).

• Known sensitivity to any ingredient in Epidiolex, including sesame and sesame oil.

• Unwillingness to refrain from alcohol consumption throughout the duration of thestudy.

• Unwillingness of females of childbearing potential to use a highly effective form ofbirth control. Acceptable methods include: hormonal contraceptives, intra-uterinedevices, bilateral tube occlusion, vasectomized partner and sexual abstinence.

• Currently enrolled in another clinical trial.

• Have suicidal plan/intent, active suicidal thoughts, or a suicide attempt in thepast 6 month prior to screening.