A Study to Investigate the Efficacy and Safety of Cannabidiol (GWP42003-P) in Children and Young Adults With Dravet Syndrome

This study is a 1:1:1 randomized, double-blind, 14-week comparison of two Dose Levels of
GWP42003-P versus placebo. A 28-day screening period prior to randomization (to establish
baseline parameters) will precede the treatment period, which will consist of a two-week
titration period followed by a 12-week maintenance period. The study will aim to determine
the efficacy, safety and tolerability of GWP42003-P compared with placebo. The High Dose
Level will be as recommended by the Data Safety Monitoring Committee (DSMC) after assessment
of safety and pharmacokinetic data from Part A of study GWEP1332. The Low Dose Level will be
defined as 50% of the High Dose Level. The first subject will not enroll into this study
until the DSMC has reviewed the safety data from Part A of study GWEP1332.

Following study completion, all subjects will be invited to continue to receive GWP42003-P
in an open label extension (OLE) study (under a separate protocol).

Key Inclusion Criteria:

- Subject must be male or female aged between 2 and 18 years (inclusive).

- Subject must have a documented history of Dravet syndrome which is not completely
controlled by current antiepileptic drugs.

- Subject must be taking one or more antiepileptic drugs at a dose which has been
stable for at least four weeks.

- All medications or interventions for epilepsy (including ketogenic diet and vagus
nerve stimulation) must have been stable for four weeks prior to screening and
subject is willing to maintain a stable regimen throughout the study.

Key Exclusion Criteria:

- Subject has clinically significant unstable medical conditions other than epilepsy.

- Subject has had clinically relevant symptoms or a clinically significant illness in
the four weeks prior to screening or randomization, other than epilepsy.

- Subject is currently using or has in the past used recreational or medicinal
cannabis, or synthetic cannabinoid based medications (including Sativex®) within the
three months prior to study entry and is unwilling to abstain for the duration for
the study.

- Subject has any known or suspected hypersensitivity to cannabinoids or any of the
excipients of the investigational medicinal products.

- There are plans for the subject to travel outside their country of residence during
the study.

- Any history of suicidal behavior or any suicidal ideation of type four or five on the
Columbia-Suicide Severity Rating Scale (Children's) at screening.