GW Pharmaceuticals and Otsuka Announce Results in First of Three Sativex(R) Phase 3 Cancer Pain Trials

- Primary endpoint did not show a statistically significant difference
for Sativex compared with placebo in reducing pain -

Conference call and webcast with GW management scheduled
at 8:00 a.m. EST, 1:00 p.m. GMT to discuss this and the Epidiolex(R)
press release issued today

LONDON and PRINCETON, N.J., Jan. 8, 2015 (GLOBE NEWSWIRE) -- GW
Pharmaceuticals plc (Nasdaq:GWPH) (AIM:GWP) ("GW") and Otsuka
Pharmaceutical Development & Commercialization, Inc., today reported
the top-line results from the first of three Phase 3 trials for the
investigational product Sativex(R) in the treatment of pain in patients
with advanced cancer who experience inadequate analgesia during
optimized chronic opioid therapy. In this first trial, Sativex (as
adjunctive treatment to optimized chronic opioid therapy) did not meet
the primary endpoint of demonstrating a statistically significant
difference from placebo.

"Although we missed the primary endpoint in this trial, based upon the
positive data seen in the Phase 2 program, we remain confident in the
ability for Sativex to relieve cancer pain in this patient population,"
stated Justin Gover, GW's Chief Executive Officer. "We have two
additional pivotal Phase 3 trials ongoing which, if positive, would
still allow us to submit a New Drug Application with the US FDA. We
look forward to results from these two further studies later this
year."

Efficacy

The primary efficacy measure of the study was a patient assessment of
pain using a 0-to-10 Numeric Rating Scale (NRS) which was analysed
using percent improvement from baseline as the primary analysis. In
addition, improvement was also analysed using a cumulative proportion
of responders analysis (CPRA), which analyses the full range of
responses achieved across the entire patient population within a trial.
In this trial, these analyses did not show a statistically significant
difference between Sativex and placebo. The secondary endpoints
followed the pattern of the primary endpoint. In this study, the United
States was the largest single recruiting country. Although not
statistically significant, the efficacy data from U.S. sites showed
more positive trends than those in non-U.S. sites. This is consistent
with data from the Phase 2b trial.

Safety

The safety profile of Sativex in this Phase 3 trial was consistent with
previous studies in this patient population. Overall, Sativex was well
tolerated. The only adverse events reported at greater than 10% for the
Sativex population were neoplasm progression (16% on Sativex vs 18% on
placebo) and somnolence (12% on Sativex vs 4% on placebo). The other
most frequently reported adverse event on Sativex was dizziness (8% on
Sativex vs 5% on placebo). Otherwise, there was little difference in
the adverse event pattern between Sativex and placebo. There were 38
(19%) withdrawals due to adverse events on Sativex compared with 29
(15%) on placebo.

Commenting on the results, Dr. Marie Fallon, Professor of Palliative
Care, University of Edinburgh and the principal investigator stated,
"We believe that cannabinoid therapy offers a potentially novel
approach as a co-analgesic to provide pain relief beyond opioid
therapy. Too many patients with advanced cancer do not attain adequate
pain relief from an opioid regimen, or experience unacceptable opioid
side effects. Whilst I am naturally disappointed that this first trial
did not achieve its primary endpoint, I remain optimistic about the
potential of Sativex and look forward to the upcoming data from the
remaining Sativex Phase 3 trials later this year."

Phase 3 Trial Design

This randomized double-blind placebo-controlled parallel-group study
recruited a total of 399 patients at clinical sites in the U.S., Mexico
and Europe. This trial evaluated Sativex at a dose range of 3-to-10
sprays per day over a 5-week treatment period with an additional
5-to-14 day stabilization period at the beginning of the trial and a
one?week follow?up at the end of the trial. Patients received the
active investigational agent or placebo as add-on treatment to
optimized opioid therapy and remained on stable doses of their
background opioid therapy during the study. Following completion of the
randomized phase, all patients were eligible to enter a long?term
extension trial.

This study is the first of three Phase 3 trials carried out by GW and
Otsuka as part of the development program aimed at securing regulatory
approval for Sativex in cancer pain from the FDA and other regulatory
authorities around the world.

A second Phase 3 pivotal trial, identical to the first, is expected to
report top line results in the second quarter of 2015. GW and Otsuka
are also in the process of conducting a third Phase 3 trial, which is
expected to enroll approximately 540 patients and designed to provide
additional information on the effects of Sativex in treating
opioid-resistant cancer pain. The third Phase 3 trial differs in design
from the first two trials, employing a two?part "enriched trial design"
akin to that which was successfully employed in the Sativex MS
spasticity trials program in Europe. The results of this third trial
are expected towards the end of 2015. GW will continue to be the holder
of the IND until the filing of a New Drug Application, which will be in
Otsuka's name.

Phase 2 Data

Sativex has previously completed a Phase 2b dose ranging study and
Phase 2a study. In these prior studies, Sativex showed statistically
significant improvements versus placebo using the same primary measure
as in the Phase 3 trial.

Sativex in Multiple Sclerosis

Sativex is approved for the treatment of spasticity due to multiple
sclerosis in 27 countries outside the U.S. In the U.S., a request for
Special Protocol Assessment has been submitted to the FDA for a
proposed single Phase 3 study in this indication.

Conference Call and Webcast Information

GW will host a conference call at 8:00 a.m. EST, 13:00 GMT today,
January 8, 2015, to comment on the Sativex results. To participate in
the call, please dial (877) 407-8133 within the U.S., (201) 689-8040
from outside the U.S. or toll free from the U.K.: 0 800 756 3429. A
replay of the call will be made available for a period of two weeks
following the conference call. To hear a replay of the call dial (877)
660-6853 (inside the U.S.) or (201) 612-7415 (outside the U.S.). A
replay of the call will also be available via the company's website
shortly after the call. For both dial-in numbers please use conference
ID 13598599. The conference call can also be heard live via the
investor relations section of the Company's website at www.gwpharm.com.

About Otsuka

Otsuka Pharmaceutical Development & Commercialization, Inc. (OPDC),
based in Princeton, New Jersey and Rockville, Maryland, discovers and
develops new compounds that address urgent, unanswered medical needs.
OPDC has numerous compounds in development to treat disorders in the
neuroscience, oncologic, and cardio-renal therapeutic areas. OPDC is
part of the Otsuka Group companies. For more information about OPDC,
visit www.otsuka-us.com.

At a global level, Otsuka Pharmaceutical Co., Ltd. contributes to the
advancement of human health through its leading position in the
challenging field of mental health and through research programs in
areas such as tuberculosis, a significant global public health issue,
and in ADPKD.

The company has a long history of individualistic thinking and
perseverance in the disease areas it enters into, illustrating more
powerfully than words how Otsuka is a "big venture" company at heart,
applying a youthful spirit of creativity in everything it does.

Otsuka Pharmaceutical Co., Ltd. is a wholly owned subsidiary of Otsuka
Holdings Co., Ltd., the holding company for the Otsuka Group that is
headquartered in Tokyo and whose origins date from 1921. The Otsuka
Group has business operations in 27 countries and regions around the
world, with consolidated sales of approximately USD 14.1 billion for
fiscal year 2013 (4/1/2013-3/31/2014.) Otsuka welcomes you to visit its
global website at https://www.otsuka.co.jp/en.

About GW Pharmaceuticals

Founded in 1998, GW is a biopharmaceutical company focused on
discovering, developing and commercializing novel therapeutics from its
proprietary cannabinoid product platform in a broad range of disease
areas. GW commercialized the world's first plant-derived cannabinoid
prescription drug, Sativex(R), which is approved for the treatment of
spasticity due to multiple sclerosis in 27 countries outside the United
States. Sativex is also in Phase 3 clinical development as a potential
treatment of pain associated with advanced cancer. GW is also advancing
an orphan drug program in the field of childhood epilepsy with a focus
on Epidiolex(R), which is in Phase 2/3 clinical development for the
treatment of Dravet syndrome and which is also expected to enter Phase
3 clinical trials in the treatment of Lennox-Gastaut syndrome. GW has a
deep pipeline of additional cannabinoid product candidates which
includes compounds in Phase 1 and 2 clinical development for glioma,
ulcerative colitis, type 2 diabetes, and schizophrenia. For further
information, please visit www.gwpharm.com.

Forward-looking statements

This news release contains forward-looking statements that reflect GW's
current expectations regarding future events, including statements
regarding financial performance, the timing of clinical trials, the
relevance of GW products commercially available and in development, the
clinical benefits of Sativex(R) and Epidiolex(R) and the safety profile
and commercial potential of Sativex and Epidiolex. Forward-looking
statements involve risks and uncertainties. Actual events could differ
materially from those projected herein and depend on a number of
factors, including (inter alia), the success of GW's research
strategies, the applicability of the discoveries made therein, the
successful and timely completion of uncertainties related to the
regulatory process, and the acceptance of Sativex, Epidiolex and other
products by consumer and medical professionals. A further list and
description of risks and uncertainties associated with an investment in
GW can be found in GW's filings with the U.S. Securities and Exchange
Commission. Existing and prospective investors are cautioned not to
place undue reliance on these forward-looking statements, which speak
only as of the date hereof. GW undertakes no obligation to update or
revise the information contained in this press release, whether as a
result of new information, future events or circumstances or otherwise.


CONTACT: Contacts at GW Pharmaceuticals

For Investors
Stephen Schultz
+ 1 401 500 6570
[email protected]

For Media
Ben Atwell /Simon Conway (UK)
+ 44 20 3727 1000
Robert Stanislaro (US)
+ 1 212 850 5657

Contact at Otsuka America Pharmaceutical, Inc.

For Media
Rose Weldon
+ 1 215 801 7644
[email protected]