Investor Presentation - StocklineGW Pharmaceuticals Nov 2018 3 • 14 cannabinoids evaluated in pre-clinical research • >80 peer-reviewed publications • Cannabinoids exported to

©2018 GW Pharmaceuticals plc | All Rights Reserved

Investor PresentationNovember 2018

FORWARD-LOOKING STATEMENTS

This presentation contains forward-looking statements that are based on our management’s beliefs and assumptions

and on information currently available to management. Forward-looking statements include information about our

current expectations for future events, including potential results of operations, the timing of clinical trials, the timing

of regulatory filings and approvals, the timing and outcomes of regulatory or intellectual property decisions, demand

for our commercially available products and products in development and the clinical benefits, safety profile and

commercial potential and potential pricing of Sativex®, Epidiolex®, and any product candidates. These forward-

looking statements are subject to known and unknown risks, uncertainties, assumptions and other factors that could

cause our actual results, performance or achievements to be materially different than any future results, performance

or achievements expressed or implied by the forward-looking statements. Forward-looking statements represent our

management’s beliefs and assumptions only as of the date of this presentation. You should read our most recent

Annual Report, as filed on Form 10-K with the Securities and Exchange Commission, including the Risk Factors set

forth therein and the exhibits thereto, and our subsequent filings with the Securities and Exchange Commission,

completely and with the understanding that our actual future results may be materially different from what we expect.

Except as required by law, we assume no obligation to update these forward-looking statements publicly, or to

update the reasons actual results could differ materially from those anticipated in the forward-looking statements,

even if new information becomes available in the future.

Disclaimers

GW Pharmaceuticals plc Investor Presentation 1Nov 2018

GW’s VISION is to be the global leader in prescription

cannabinoid medicines, developing and commercializing

pharmaceutical products which address clear unmet needs

Nov 2018 GW Pharmaceuticals plc Investor Presentation 2

GW Pharmaceuticals

Nov 2018 3

• 14 cannabinoids evaluated in pre-clinical

research

• >80 peer-reviewed publications

• Cannabinoids exported to >35 countries

for research

• >50 Phase 2/3 clinical trials

• >55,000 patient-years of human safety

data

• Sativex® approved in >25 countries (ex-

US) for relief of MS spasticity

• Epidiolex® approved by FDA (DEA

Schedule V)

• Launched in U.S. November 1

• MAA under review by EMA (in EU)

• US commercial launch team in place

• EU commercial infrastructure build

ongoing

• Increased scale commercial

manufacturing in place

RESEARCH DEVELOPMENT COMMERCIALIZATION

20years

experience in researching and

developing novel Rx

cannabinoid medicines

~500 person

in-house

teamwith expertise in

bringing drugs to

regulatory approval in

US and ROW

World Leader in Cannabinoid ScienceGW Pharmaceuticals plc Investor Presentation

Epidiolex® (cannabidiol) oral solution

Treatment-Resistant Epilepsy Overview

• Positive data from all four Phase 3 placebo-controlled trials in initial target orphan

indications of Dravet syndrome and Lennox-Gastaut syndrome (LGS)

• Two Phase 3 studies published in The New England Journal of Medicine and one

Phase 3 study in The Lancet

• Epidiolex approved by FDA on June 25, 2018, moved into Schedule V by DEA

• EMA submission accepted for review, expected decision in Q1 2019

• Novel mechanism of action in epilepsy

• “Real-world” experience in Epidiolex use

- Data from >1,000 patients in compassionate use program show treatment

effect and safety across a range of severe epilepsy types

• Active lifecycle management plan, including additional target orphan indications

Nov 2018 4

Epidiolex® (cannabidiol) is an investigational product outside of the United States of America

GW Pharmaceuticals plc Investor Presentation

Epidiolex launched in

the U.S. on November

1st 2018 – now

available by

prescription

• 3.4 million US patients with epilepsy (~470,000 children)

- ~ One third of patients are pharmacoresistant with seizures persisting

despite multiple antiepileptic drugs (AEDs)

• Childhood-onset epilepsy

- Multiple distinct orphan syndromes, almost none with a specific indicated

therapy

- Many syndromes highly resistant to currently available AEDs

- Seizures continue into adulthood

• Dravet syndrome and LGS represent two of the most difficult-to-treat

epilepsy syndromes

- Multiple seizure types, developmental delay, high risk of SUDEP

- Highly refractory even with current medications, polytherapy generally

required

• Physicians seek new treatment options

- Majority of physicians not satisfied with current therapeutic options

Significant Unmet Need in Epilepsy

GW Pharmaceuticals plc Investor Presentation 5

Sources: Sander JW, Epilepsia. 1993;34(6):1007; Picot et al, 2008 ; Kwan P, Brodie MJ. N

Engl J Med. 2000;342:314-319; Kwan P, Brodie MJ, CNS Spectr. 2004;9(2):110

3

Nov 2018

Source: Picot et al, 2008; Kwan P, Brodie MJ. N Engl J Med. 2000;342:314-319; Kwan P, Brodie MJ, CNS Spectr. 2004;9(2):110, Morgan Stanley research (2015)

The Epidiolex® Story: IND to FDA Approval in 4 Years

6

Q4 ‘12

First child

treated with

Epidiolex

Q1 ‘14

EAPs

(Expanded

Access

Programs)

initiated

Q2-4 ‘15

3 Phase 3

studies in

Dravet and

LGS started

and enrolled

Q2 ‘14

FDA grants GW

IND. Formal

GW CBD

development

program begins

2016

Positive topline

results in

Dravet & LGS

pivotal studies

Oct 2017

Epidiolex

NDA

submission

#1

2,000

patients have been treated with Epidiolex

Dec 2017

Epidiolex

Europe

submission

Q2 2017

Dravet trial

results

published

in NEJM

Jan 2018

LGS trial

results

published in

The Lancet

June 25, 2018

Epidiolex

approved by

the FDA(Sept. 28: Moved to

DEA Schedule V)

Q1 2018

2nd LGS trial

results

published in

NEJM

Nov 2018 GW Pharmaceuticals plc Investor Presentation

Nov 1 2018

Epidiolex

launched in

the U.S.

• FDA authorized, physician-sponsored expanded access

program (EAP) initiated in early 2014

- Children and young adults with multiple etiologies, all with

treatment-resistant epilepsy

- ~40 physician site EAPs and 6 US state sponsored EAP

programs

- Over 1,000 patients approved for treatment by FDA

• Most recent EAP data presented in abstracts at AES 2017

- Long-term (96-week) Epidiolex safety and treatment effect data

- All Children and Adults with Treatment-Resistant Epilepsies

(Bebin et al, 2017)

- Patients with LGS & Dravet syndrome (Laux et al, 2017)

- For both convulsive and total seizures, median % reductions

and ≥50%, ≥75% and 100% responder rates were consistent

across all time points

- CBD was generally well tolerated, adverse events (AEs) were

consistent with those seen in previous pivotal and expanded

access reports

Epidiolex® Expanded Access Program


Patients with LGS and Dravet Syndrome Only

AES 2017 – EAP Median % Reduction in Seizures

Convulsive Seizures Total Seizures

Convulsive Seizures Total Seizures

All Patients with TRE

Epidiolex Clinical Program

Epidiolex® Clinical Program Overview

9

GW makes Epidiolex

available to the most

needy patients

through an

innovative

compassionate use

program

Nov 2018

Ph

ysic

ian

Sp

on

so

red

GW

Sp

on

so

red

Dravet

Syndrome

Lennox-Gastaut

Syndrome

Tuberous

Sclerosis

Complex

Childhood

Epilepsy

Syndromes

2015

Phase 3 (n=120) — Positive




Phase 3 (n=210) — Fully Recruited

Ongoing Treatment Data from ~ 1,000 patients — Other Epilepsies

FDA

Approval

FDA approval on

June 25th, 2018

Rescheduled by

DEA to Schedule V

Launched in the

U.S. on Nov 1, 2018

MAA submission

decision expected

in Q1 2019

2016 2017 2018

NDA MAA

2019


Phase 3 Dravet 2 (Multiple Dose Cohorts) Trial Principal Efficacy Results


49P=0.0069 44

P=0.0332

26

0

10

20

30

40

50

60

≥50%

Reduction in Convulsive Seizures Convulsive Seizure Responder Rates

Treatment Period

% r

eduction

% P

atients

CBD 20 mg/kg/day (n=67), CBD 10mg/kg/day (n=67), placebo (n=65)

Source: GW company press release – 26 November 2018

4649

27

0

5

10

15

20

25

30

35

40

45

50

Treatment Period (Primary)

P=0.0095P=0.0299

Phase 3 LGS 2 (Multiple Dose Cohorts) Trial Principal Efficacy Results


62

40

25

63

36

11

43

15

3

0

10

20

30

40

50

60

70

≥25% ≥50% ≥75%

*

†

*

‡

‡

*

Reduction in Drop Seizures Drop Seizure Responder Rates

Treatment Period

Media

n %

reduction /

28 d

ays

% P

atients

*p<0.05†p<0.01‡p<0.001

†p<0.01

▪ 5 CBD 20 mg/kg, 3 CBD 10 mg/kg, and 1 placebo patient achieved drop seizure freedom during maintenanceSource: Cannabidiol (CBD) Significantly Reduces Drop Seizure Frequency in Lennox-Gastaut Syndrome (LGS): Multi-Center, Randomized, Double-Blind, Placebo-Controlled Trial (GWPCARE3)

A.D. Patel, O. Devinsky, J.H. Cross, V. Villanueva, E. Wirrell, K. VanLandingham, C. Roberts, D. Checketts, S. Zuberi, American Academy of Neurology Annual Meeting

42

47

3740

1719

0

5

10

15

20

25

30

35

40

45

50

Treatment Period(Primary)

Maintenance Period

CBD 20 mg/kg/day (n=76) CBD 10 mg/kg/day (n=73) Placebo (n=76)

†

†

†

†

Phase 3 Safety Profile

• Consistent adverse reaction profile across pivotal trials

• Most common AEs (>10% of patients) in Phase 3 trials include:

- Somnolence, decreased appetite, diarrhea, transaminase elevations, fatigue, malaise,

asthenia, rash, insomnia, sleep disorder and poor-quality sleep, and infections.

- Warnings & Precautions related to hepatocellular injury and somnolence & sedation are

included in the US Prescribing Information

• Low withdrawal rates seen throughout clinical program

• Elevations in hepatic transaminases have been reported, most commonly with

concomitant valproate; none met criteria for serious liver injury; all elevations

resolved–most while on treatment

- Physicians routinely monitor liver function in patients with epilepsy as there are a number

of approved AEDs that are associated with elevations in transaminases

- Monitoring recommendations and lower starting dose are included in US package

insert to help physicians manage potential liver risks

GW Pharmaceuticals plc Investor Presentation 12

Across the Phase 3

program, Epidiolex

was generally well-

tolerated, with most

AEs reported as mild

or moderate

Nov 2018

• Selection of this indication driven by encouraging EAP data

• Single Phase 3 pivotal trial now fully enrolled – data H1 2019

• sNDA H2 2019

• Tuberous Sclerosis Complex (~25,000 US TSC patients with

treatment-resistant seizures)

- TSC is a genetic disorder that results from a mutation in tumor

suppressor genes TSC1 or TSC2 and causes non-malignant tumors to

form in different organs (primarily the brain, eyes, heart, kidney, skin and

lungs)

- Of TSC patients with epilepsy, 70% experience seizure onset in their first

year of life

- Co-morbidities include: cognitive impairment (50%), autism spectrum

disorders (up to 40%), neurobehavioral disorders (over 60%)

3rd Target Indication:Tuberous Sclerosis Complex (TSC)


Source: Tuberous Sclerosis Alliance; Child Neurology Foundation; Infantile Spasms Project

• Rett syndrome is a rare, non-inherited, X-linked neurodevelopmental disorder

- Affects approximately 1 in 10,000 to 15,000 live female

births

- No approved treatments for Rett syndrome

- The condition affects predominantly females and results

in abnormal neuronal development and function in

affected children.

- The symptomatology of Rett is progressive, with early

onset from about 6–18 months of life, followed by a

rapid destructive phase at the age of 1-4 years.

• Clinical evidences from open label investigations in

patients with refractory epilepsy suggest that Epidiolex

may have beneficial effects on cognition, behavior and quality of life, which could benefit patients

with Rett syndrome.

• Single Phase 3 pivotal trial expected to start in Q2 2019

4th Target Indication:Rett Syndrome


Commercialization

Commercial Manufacturing

16

Growing &

Harvesting

Drying & Processing

Crystallisation

(API)

Drug Product

Manufacture

Bottling & Labeling

GMP

Non-GMP

• GW has operated under current Good

Manufacturing Practices (cGMP) licenses

issued outside the US since 2005

• Manufacturing scaled through in-house and

3rd party facilities

• Further increases in scale anticipated in

2018 and beyond to meet anticipated global

demand

• FDA pre-approval inspections completed in

2018 with no Form 483 citations

Extraction

Nov 2018 GW Pharmaceuticals plc Investor Presentation

• Orphan Designation

• 7 years in the US plus expected 6-month pediatric extension (runs concurrent with 5-year exclusivity for new molecular entity)

• 10 years in the EU plus expected 2 years pediatric extension

• Intellectual Property

• Pursuing a strategy to have patents issued to provide protection beyond Orphan Designation

• Current portfolio includes multiple distinct patent families in the treatment of epilepsy and formulations

• To date, 12 issued patents with expiry to 2035

• 6 patents currently listed in the Orange Book (with 2 recent granted patents expected to follow)

• Additional patent applications expected as new data is generated

• Life-cycle management through new indications, formulation improvements, combinations and additional commercial geographies

• Proposed new formulations include liquid, solid dose, intravenous

Epidiolex® Commercial Exclusivity


Patent

Protections

Orphan

Exclusivity

Life-Cycle

Management

Epidiolex® Orange Book Listable Patent Portfolio(applications in public domain – several additional patents filed, not yet available through USPTO website)

20Nov 2018

Patent Primary Claim Status

US 9,474,726 A method of treating febrile infection related epilepsy syndrome (FIRES) comprising administering CBD to a subject. Granted

US 9,956,184 A method of reducing seizure frequency in LGS with concomitant CBD and clobazam, wherein the CBD dose is >10

mg/kg/day or greater and the purity of the CBD is greater than 98%.

Granted

US 9,949,937 A method of reducing seizure frequency in Dravet syndrome with concomitant CBD and clobazam, wherein the CBD

dose is >10 mg/kg/day or greater and the purity of CBD is greater than 98%.

Granted

US 9,956,183 A method of reducing seizure frequency in LGS or Dravet syndrome with concomitant CBD and clobazam, wherein the

dose of clobazam is reduced and the purity of CBD is greater than 98%.

Granted

US 9,956,186 A method of reducing convulsive seizures in LGS with CBD, wherein the CBD dose is >10 mg/kg/day and the purity of

CBD is greater than 98%.

Granted

US 9,956,185 A method of reducing convulsive seizures in Dravet syndrome with CBD, wherein the CBD dose is >10 mg/kg/day and

the purity of CBD is greater than 98%.

Granted

US 15/449,402 A method of reducing drop seizures in Dravet syndrome with CBD, wherein the dose of CBD is about 20 mg/kg/day and

the purity of CBD is greater than 98%.

Granted

US 15/449,535 A method of reducing drop seizures in LGS with CBD, wherein the dose of CBD is about 20 mg/kg/day and the purity of

CBD is greater than 98%.

Granted


• Epidiolex launched in the U.S. on November 1st, 2018

- Team actively promoting product to physicians

- Extensive communications campaign in place

• In the US we are using our wholly-owned subsidiary, Greenwich Biosciences

Inc., to commercialize our products

• Medical affairs organization in place for over two years, including 15 Medical

Science Liaisons (MSLs)

• U.S. sales organization fully recruited and trained, comprising two national

directors, eight regional managers plus 66 Neurology Account Managers

- ~5,000 target physicians

• Active engagement with U.S. payors ongoing

• Projected weighted average gross price in the first year of $32,500

• U.S. supply chain platform in place

Epidiolex® - U.S. Commercialization Status


The Caregiver/Patient Campaign Features Actual EPIDIOLEX Patients w/Documentary Style Videos to bring their stories to life……

Before starting EPIDIOLEX, Cameron was having close to

60 drop seizures per day

Cameron’s Story

Jon was a happy, active child until complications from an operation led to LGS and

uncontrolled Seizures

Jon’s Story

Grace was diagnosed with Dravet Syndrome as in infant, experiencing as many as 400

atonic seizures a day

Grace’s Story

• We expect an outcome to the EMA regulatory review in Q1 2019

• Commercial leadership team consisting of experienced, epilepsy disease

experts fully recruited and in place

• Planning for launches in the five major European markets in 2019

- Significant progress in building out the local country organizations in these 5

markets

- Expected to included 17 sales professionals, 17 MSLs

- Second wave of countries expected to launch in 2020

• Progressing pricing and reimbursement, medical and pre-commercial activities

required to deliver a successful European launch

Epidiolex® - Europe Commercialization Status


Additional Programs, Financial

Information and Upcoming Milestones

• Cannabis plant is a unique source of >100

cannabinoid molecules potentially capable of targeting

diseases across therapeutic areas and mechanisms

- TRP channels, adenosine re-uptake, serotonin

receptors, endocannabinoid system

• GW has a deep pipeline of additional cannabinoid

product candidates

• Focus on orphan pediatric neurologic conditions within

epilepsy, autism, NHIE, schizophrenia

• Existing physician relationships through Epidiolex

program

• U.S. development and commercialization rights to

Sativex fully owned by GW; plans underway to

determine FDA regulatory pathway for MS spasticity

GW’s Cannabinoid Platform:A Proprietary Growth Engine Beyond Epidiolex®


• Oromucosal spray of a formulated botanical extract of cannabis that contains the principal cannabinoids delta-9-

tetrahydrocannabinol (THC) and cannabidiol (CBD) in a 1:1 ratio

• Approved in >25 countries outside the United States for the treatment of spasticity due to Multiple Sclerosis (MS).

Product is sold via marketing partners

• Potential for multiple indications

Sativex® - New U.S. Late Stage Pipeline Product

24Nov 2018 GW Pharmaceuticals plc Investor Presentation

- 3 positive Phase 3 trials in MS spasticity

- >10 additional placebo-controlled trials completed in models of peripheral

and central neuropathic pain, other MS symptoms, rheumatoid arthritis

- Planning pivotal program in neuropathic pain/other neurological symptoms

• GW reacquired full rights to develop and commercialize Sativex in U.S.

(Dec 2017)

• Represents a new wholly-owned late-stage U.S. asset

• We expect to evaluate the optimal route to submit a NDA for MS

spasticity. Meeting with FDA expected to take place Q4 18

• CBDV

- Expanded access IND to treat seizures associated with autism in 20 patients underway

- Data on 5 patients to be presented at AES Annual Meeting – Initial data suggest CBDV exhibited AED properties with positive effects on general

autism scales (Source: Barnes AES abstract)

- Investigator-led 100 patient placebo-controlled trial in autism due to commence in Q4 2018

- Open-label study in Rett Syndrome expected to commence in Q1 2019

- Exploring next steps in epilepsy

• Schizophrenia (GWP42003)

- Positive top line results from exploratory Phase 2 placebo-controlled clinical trial in 88 patients with schizophrenia who had

previously failed to respond adequately to first line antipsychotic medications

- Potential for product with novel mechanism distinct from the dopamine D2 receptor augmentation of standard antipsychotics

• Glioblastoma (THC:CBD)

- Positive Phase 2 placebo-controlled data

- THC:CBD + TMZ had an 83% one year survival rate compared with 44% for patients on placebo (TMZ only) (p=0.042)

- Median survival for the THC:CBD group was over 662 days compared with 369 days in the placebo group

- THC:CBD generally well tolerated

Selected Additional Pipeline Candidates

25Nov 2018 GW Pharmaceuticals plc Investor Presentation

Key Financial Data


Clean up

ICON

Cash at 30 Sept 2018 $354.9m

Net cash from October financing $324.2m

Q ending 31 December cash outflow guidance $90m–$100m

Share Capital Current Options Fully Diluted

ADS/m 28.3 1.2 29.5

Upcoming Milestones/Newsflow


Expected Timing

EPIDIOLEX REGULATORY

EMA decision Q1 2019

EPIDIOLEX DATA

American Epilepsy Society annual meeting Dec 2018

Phase 3 tuberous sclerosis complex trial data H1 2019

Presentation of Dravet 2 data at medical meeting H1 2019

EPIDIOLEX COMMERCIAL

U.S. launch update Q1 2019

European product launches 2019

PIPELINE

FDA meeting to determine Sativex NDA requirements Q4 2018

Epidiolex in Rett syndrome start H1 2019

CBDV investigator-led placebo control trial in autism start Q4 2018

CBDV open label in Rett syndrome trial start Q4 2018

Thank You

GW Pharmaceuticals plc

NASDAQ: GWPH

Stephen Schultz, VP Investor Relations

[email protected]

+ 1 401-500-6570

Documents

Investor Presentation - StocklineGW Pharmaceuticals Nov 2018 3 • 14 cannabinoids evaluated in pre-clinical research • >80 peer-reviewed publications • Cannabinoids exported to