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

The goal of this clinical trial is to learn the best way to switch children with Lennox-Gastaut Syndrome (LGS) or Dravet Syndrome (DS) taking 'artisanal' (non pharmaceutical-grade) cannabidiol (CBD) to Epidiolex for treatment of seizures. The main questions it aims to answer are:

* How well does a gradual switch from 'artisanal' CBD to Epidiolex work?
* Does the same dose of Epidiolex as 'artisanal' CBD work best?
* What side-effects or medical problems do participants have when switching from 'artisanal' CBD to Epidiolex?

Researchers will examine how successful switching from 'artisanal' CBD to Epidiolex is.

Participants will:

* Gradually increase their dose of Epidiolex and reduce their dose of 'artisanal' CBD until they are taking just Epidiolex
* Visit the clinic five times over 20 weeks for checkups and tests
* Keep a diary of their seizures, symptoms and the number of times they use a rescue seizure medication


Eligibility Criteria:
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 of neurodevelopmental 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 for participation. If the participant is not qualified or unable to provide written consent based on age, development, intellectual capacity or other factors, the parent or legally authorized representative must provide written informed consent on their behalf.
* Must be on a stable dose of a licensed artisanal cannabidiol (CBD) product as maintenance 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 a minimum 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 medically necessary change(s) are required for safety events.
* Participants with a vagal nerve stimulator (VNS) must have the following conditions met:

  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 28 days prior to screening (visit 1) and expected to remain stable throughout the entire study.
* Participant and/or caregiver must be willing to maintain a seizure diary throughout the 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, in the opinion of the investigator, could place the participant at increased risk or interfere with the results of the study.
* Hepatic impairment at screening (visit 1) defined as either of the following conditions:

  1. ALT or AST \> 5x upper limit of normal (ULN).
  2. ALT or AST \> 3x ULN and total bilirubin \>2x ULN (or international normalized ratio \>1.5).
* Known sensitivity to any ingredient in Epidiolex, including sesame and sesame oil.
* Unwillingness to refrain from alcohol consumption throughout the duration of the study.
* Unwillingness of females of childbearing potential to use a highly effective form of birth control. Acceptable methods include: hormonal contraceptives, intra-uterine devices, 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 the past 6 month prior to screening.