– Four Phase 3 epilepsy clinical trials underway — First Phase 3 trial fully enrolled –

– U.S. operations established with appointment of new President and headquarters –

– Conference Call Today at 8:00 a.m. EDT, 1:00 p.m. BST –

LONDON, Aug. 6, 2015 (GLOBE NEWSWIRE) — GW Pharmaceuticals plc (GWPH) (GWP.L) (“GW,” “the Company” or “the Group”), a biopharmaceutical company focused on discovering, developing and commercializing novel therapeutics from its proprietary cannabinoid product platform, announces financial results for the third quarter and nine months ended 30 June 2015.

RECENT OPERATIONAL HIGHLIGHTS

• U.S. operations update:
  • Seasoned industry executive Julian Gangolli appointed as President, North America and to the GW Board of Directors as Executive Director
  • GW CEO Justin Gover relocates to California from London
  • U.S. operations now comprise 25 employees and will be headquartered in Carlsbad, California
• Epidiolex^(R) (CBD) childhood epilepsy program:
  • Dravet syndrome — First Phase 3 pivotal trial now fully enrolled with a total of 120 patients, exceeding original target of 100 patients. Top-line data expected early Q1 2016. Second Phase 3 trial on track for top-line data in Q1 2016
  • Lennox-Gastaut syndrome — Two Phase 3 trials underway and on track for top-line data in Q1 2016
  • Tuberous Sclerosis Complex — Phase 3 trial expected to start in Q4 2015
  • Additional clinical development for Epidiolex beyond initial three indications expected to commence during 2016
  • Expanded access program:
    • Approximately 320 children on treatment at 19 U.S. clinical sites
    • Approximately 750 children authorized for treatment by FDA under Expanded Access Treatment INDs and 4 U.S. State programs
    • Additional data expected Q4 2015
• Orphan/Neurology cannabinoid pipeline product candidates:
  • Phase 2a CBD schizophrenia study complete with data expected H2 2015
  • Phase 2 Cannabidivarin (CBDV) epilepsy study underway with data expected in H1 2016
  • Orphan Drug and Fast Track Designations granted for intravenous CBD in the treatment of Neonatal Hypoxic-Ischemic Encephalopathy (NHIE) from the FDA and recently received from the EMA
  • Plans advancing to commence clinical trials within field of autism spectrum disorders in 2016.
  • Phase 1b/2a study of GWP42002:GWP42003 for the treatment of Recurrent Glioblastoma Multiforme (GBM) is fully recruited with data expected in mid-2016
• Other cannabinoid pipeline product candidates
  • Second and third Sativex Phase 3 cancer pain trials expected to read out in H2 2015 – First trial did not show a statistically significant difference for Sativex compared with placebo
  • Phase 2 study of GWP42004 in type-2 diabetes underway with data expected in 2016
• Extensive pre-clinical progress in conjunction with network of academic collaborators addressing:
  • New therapeutic targets:
    • Autism Spectrum Disorders
    • Duchenne Muscular Dystrophy
    • A range of oncology programs
    • Cachexia
  • Mechanisms of action of Epidiolex in epilepsy

FINANCIAL HIGHLIGHTS

• Follow-on offering in May 2015 raising total net proceeds after expenses of $193.3 million ([Pounds]127.5 million).
• Revenue for the nine months ended 30 June 2015 of [Pounds]22.9 million ($36.0 million) compared to [Pounds]22.6 million for the nine months ended 30 June 2014.
• Loss for the nine months ended 30 June 2015 of [Pounds]32.3 million ($50.8 million) compared to [Pounds]14.9 million for the nine months ended 30 June 2014.
• Cash and cash equivalents at 30 June 2015 of [Pounds]254.0 million ($398.9 million) compared to [Pounds]164.5 million as at 30 September 2014.

“GW has unprecedented momentum with four phase 3 trials progressing for Epidiolex in pediatric epilepsy as well as a full pipeline of other early and late stage clinical programmes across a range of indications”, stated Justin Gover, GW’s Chief Executive Officer. “We expect to carry this momentum through the remainder of 2015 as we approach pivotal Phase 3 data for Epidiolex and GW moves confidently forward with preparations for an expected NDA submission in 2016 as well as continuing to build a high quality U.S. commercial infrastructure ahead of commercial launch.”

Conference Call and Webcast Information

GW Pharmaceuticals will host a conference call and webcast to discuss the 2015 third quarter financial results today at 8:00 a.m. EDT / 1:00 p.m. BST. To participate in the conference call, please dial 877-407-8133 (toll free from the U.S. and Canada), or 0800-756-3429 (toll free from the UK) or 201-689-8040 (international). Investors may also access a live audio webcast of the call via the investor relations section of the Company’s website at https://www.gwpharm.com. A replay of the call will also be available through the GW website shortly after the call and will remain available for 30 days. Replay Numbers: (toll free):1-877-660-6853, (international):1-201-612-7415. For both dial-in numbers please use conference ID #13615856.

GW Pharmaceuticals plc

(“GW” or “the Company” or “the Group”)

2015 Third Quarter Financial Results

GW Overview

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. In 16 years of operations, GW has established a world leading position in the development of plant-derived cannabinoid therapeutics through its proven drug discovery and development processes, intellectual property portfolio and regulatory and manufacturing expertise. 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. GW is advancing an orphan drug program in the field of childhood epilepsy with a focus on Epidiolex^(R), which is in Phase 3 clinical development for the treatment of Dravet syndrome and Lennox-Gastaut syndrome and which is also expected to enter Phase 3 clinical trials in the treatment of Tuberous Sclerosis Complex by the end of 2015. GW has a deep pipeline of additional cannabinoid product candidates which includes Sativex in Phase 3 clinical development as a potential treatment of pain associated with advanced cancer, as well as compounds in Phase 1 and 2 development for both orphan (Neonatal Hypoxic Ischemic Encepholapthy and glioma) and non-orphan (type 2 diabetes and schizophrenia) indications.

U.S. Operations Update

In June 2015, Julian Gangolli joined GW in the newly created position of President, North America, and has been appointed to the GW Board of Directors. Previously, Mr Gangolli was President of the North American Pharmaceutical division of Allergan Inc., with responsibility for a 1,400-person integrated commercial operation with sales exceeding $3.8 billion in 2014. GW also announced the relocation of the Company’s CEO, Justin Gover, to the U.S. Together, Mr. Gangolli and Mr. Gover will lead GW’s growth in the U.S. and prepare for the expected NDA submission and build the in-house U.S. commercial infrastructure required for a successful commercial launch of Epidiolex. In total, GW now has 25 U.S.-based employees. Mr. Gangolli and Mr. Gover will be based at the U.S. operation in Carlsbad, California.

U.S. Follow-on Offering

In May 2015, GW successfully completed a U.S. follow-on offering on the NASDAQ Global Market issuing a total of 1,840,000 American Depositary Shares (“ADSs”) at a price of $112.00 per ADS. This total included the full exercise of the underwriters option to purchase an additional 240,000 ADSs and resulted in total net proceeds after expenses of approximately $193.3 million ([Pounds]127.5 million). The funds raised in this offering are primarily intended to support further expansion of GW’s Epidiolex manufacturing capability and build-up of inventory in preparation for U.S. launch, if Epidiolex is approved; clinical development of other orphan indication opportunities for Epidiolex, with an initial focus on Tuberous Sclerosis Complex; the advancement of other pipeline opportunities, including an intravenous CBD formulation in the treatment of Neonatal Hypoxic-Ischemic Encephalopathy (NHIE); pre-launch commercialization activities for Epidiolex in the United States; and for other general corporate purposes.

Epilepsy Drug Development Programs

GW’s epilepsy franchise centers around two product candidates, Epidiolex, a liquid formulation of pure plant-derived cannabidiol (CBD), and GWP42006 (CBDV). GW is currently pursuing the development of CBD for a series of individual orphan epilepsy-related indications providing GW with significant new market opportunities. These development programs are funded completely by GW and GW retains all rights to commercialize any and all products that evolve from these programs.

Epidiolex^(R)

GW is undertaking a formal development program for Epidiolex in the field of severe, drug-resistant childhood epilepsy with initial focus on conducting formal development programs for Epidiolex in the treatment of three indications – Dravet syndrome, Lennox-Gastaut syndrome (LGS) and Tuberous Sclerosis Complex (TSC). The Company has to date received Orphan Drug Designation from the U.S. Food and Drug Administration (FDA) for Epidiolex for the treatment of both Dravet syndrome and LGS. Additionally, GW has received Fast Track Designation from the FDA and Orphan Designation from the European Medicines Agency (EMA) for Epidiolex for the treatment of Dravet syndrome.

Investigations to clarify the pharmacological targets which underlie CBD’s anticonvulsant effects are on-going. Overall, CBD is likely to be acting via more than one mechanism of action with the effect of reducing neuronal hyperexcitability. Importantly, the anti-seizure effects of CBD are not dependent on cannabinoid receptors, nor on sodium channels.

Dravet Syndrome

GW commenced a Phase 2/3 clinical trial of Epidiolex for Dravet syndrome in October 2014. This trial is designed as a two-part randomized double-blind, placebo-controlled parallel group dose escalation, safety, tolerability, pharmacokinetic and efficacy trial of single and multiple doses of Epidiolex to treat Dravet syndrome in children who are not responding adequately to other anti-epileptic drugs. Part one was completed in February 2015, and included a dose-ranging pharmacokinetic and safety evaluation in a total of 34 patients over a 3 week treatment period.

Following a review of the Part A data by an independent panel, Part B of the trial commenced in March 2015 and is a Phase 3 pivotal placebo-controlled safety and efficacy evaluation of Epidiolex over a 3-month treatment period. The sample size for this trial was increased from an original 80 patients to 100 patients. Recruitment into the study has been rapid, with even the revised target sample size of 100 patients being exceeded, and this study is now fully recruited with a total of 120 patients.

In April 2015, GW commenced an additional dose-ranging Phase 3 trial in Dravet syndrome which is recruiting 150 patients. Recruitment is going well in this study.

GW expects to report top-line results from the first pivotal safety and efficacy study early in the first quarter of 2016 and results from the second Phase 3 trial in the first quarter of 2016. Both of these studies will be substantially larger than any previously published controlled trial in Dravet syndrome The primary measure of efficacy in both trials will be the comparison between Epidiolex and placebo in the percentage change from baseline in number of convulsive seizures per month.

Lennox-Gastaut Syndrome (LGS)

GW has commenced two Phase 3 trials of Epidiolex in LGS. The first trial is expected to recruit 100 patients and the second is expected to recruit 150 patients. The Company expects to report top-line results from both trials in the first quarter of 2016. The primary measure of efficacy in both trials will be the comparison between Epidiolex and placebo in the percentage change from baseline in number of drop attacks per month.

Tuberous Sclerosis Complex (TSC)

Based on the findings in the physician-led expanded access program, GW announced earlier this year that its third target indication will be TSC and expects to commence Phase 3 clinical development in the fourth quarter of 2015. TSC is a genetic disorder that causes non-malignant tumors to form in many different organs, with the brain and skin being the most commonly affected tissues. TSC results from a mutation in tumor suppression genes TSC1 or TSC2 and is estimated to affect approximately 50,000 patients in the United States. The most common clinical feature of TSC is epilepsy, which occurs in 75 − 90% of patients, about 70% of whom experience seizure onset in their first year of life. Approximately 60% of these TSC patients (or approximately 25,000 of patients in the United States) have treatment-resistant seizures. There are significant co-morbidities associated with TSC including cognitive impairment in 50%, autism spectrum disorders in up to 40% and neurobehavioral disorders in over 60% of individuals with TSC.

Epidiolex U.S. Expanded Access Program

In parallel with the Company’s formal clinical trial program, the FDA has granted 20 intermediate expanded access INDs to independent physician investigators in the U.S to treat a total of approximately 450 children and young adults suffering from intractable epilepsy with Epidiolex. In addition, the FDA has granted further INDs to treat 300 additional patients under expanded access programs supported by 4 U.S. states and for which GW is supplying Epidiolex. The FDA may authorize expanded access programs to facilitate access to investigational drugs for treatment use for patients with a serious or immediately life-threatening disease or condition who lack therapeutic alternatives.

On 22 April 2015, at the American Academy of Neurology Annual Meeting, physician reports of clinical effect data on 137 children and young adults with treatment-resistant epilepsy treated with Epidiolex under expanded access INDs for a period of at least 12 weeks was presented in a poster by Devinsky, O. et al. These data are from eleven U.S. hospital sites. In addition, physician reports of safety data were presented on 213 patients (137 patients with 12 weeks treatment effect data plus additional patients still in their first 12 weeks of treatment or who withdrew from treatment). These data, which are available on the GW corporate website, suggest consistent signals of clinical safety and efficacy with good tolerability and a low rate of withdrawls. The Epidiolex response is seen particularly in the Dravet syndrome and LGS patient populations, but is also evident across a range of other types of pediatric epilepsy.

GW expects additional clinical effect data to be reported at upcoming medical meetings during the fourth quarter of 2015.

CBDV (cannabidivarin) Development Program

GW is developing a second epilepsy product candidate, GWP42006, which features the non-psychoactive cannabinoid CBDV as the primary cannabinoid. CBDV is distinct in chemical structure to CBD and has shown anti-seizure properties across a range of in vitro and in vivomodels. GW has completed a Phase 1 trial of GWP42006 by the oral and intravenous route in 66 healthy subjects. In this trial, GWP42006 was well tolerated even at the highest tested dose. There were no serious or severe adverse events, nor any withdrawals due to adverse events.

In May 2015, GW commenced a Phase 2 study of GWP42006 in patients with epilepsy and expects data from that study in the first half of 2016. GWP42006 has the potential for development in the field of pediatric epilepsy as well as the broader epilepsy market.

CBD/CBDV Intellectual Property Portfolio

GW’s patent portfolio related to the use of CBD and/or CBDV includes fourteen patent families containing one or more pending and/or issued patents with claims in the treatment of epilepsy, compositions, extraction techniques, CBD and CBDV extracts and highly purified plant-derived CBD. These include Notices of Allowance from the U.S. Patent and Trademark Office for patent applications protecting the use of CBD in the treatment of partial seizures and for CBDV in the treatment of patients with epilepsy. The issued patents from these applications will provide an exclusivity period until June 2030 and March 2031 respectively.

Other Orphan/Neurology Pipeline Programs

Schizophrenia

GW’s product candidate, GWP42003, has shown notable anti-psychotic effects in accepted pre-clinical models of schizophrenia and has also demonstrated the ability to reduce the characteristic movement disorders induced by currently available anti-psychotic agents. The mechanism of GWP42003 does not appear to rely on the dopamine D2 receptor augmentation of standard antipsychotics and therefore has the potential to offer a novel treatment option in this therapeutic area.

An 80-patient placebo-controlled Phase 2a trial of GWP42003 for the treatment for schizophrenia is now complete with top line data expected in the second half of 2015.

Neonatal Hypoxic-Ischemic Encephalopathy (NHIE)

NHIE is acute or sub-acute brain injury resulting from deprivation of oxygen during birth (hypoxia). GW estimates 6,500 to 12,000 cases of NHIE occur in the U.S. each year. Of these, 35% are expected to die in early life and 30% are expected to develop persistent neurologic disability. There are currently no FDA-approved medicines specifically indicated for NHIE. The current standard of care for NHIE patients is to induce whole-body hypothermia. Even if a patient is put into induced hypothermia there is still a significant rate of morbidity and mortality, with a meta-analysis of the available data revealing a 27% death rate. Among the patients who survive NHIE, 28% suffer from major neurodevelopment issues and 26% develop Cerebral Palsy.

GW intends to commence a clinical development program with the FDA and expects to start a Phase 1 clinical study in healthy volunteers for an intravenous CBD formulation in the treatment of NHIE in the fourth quarter of 2015. GW has received Orphan Drug and Fast Track Designations from the FDA for CBD for the treatment of NHIE and has recently received Orphan Designation from the European Medicines Agency for the treatment of Perinatal Asphyxia, an alternate term that describes the same condition.

Autism Spectrum Disorders

Many of the pediatric intractable epilepsy conditions within the Epidiolex Expanded Access Program share considerable overlap with Autism Spectrum Disorders (ASD). Early clinical observations from treating physicians suggest a potential role for cannabinoids in addressing problems associated with ASD; they may be able to reverse deficits in cognition, behaviour and communication. Consequently, there are several ongoing initiatives within GW to evaluate a range of cannabinoids in pre-clinical models of ASD, with a focus on, but not limited to, those caused by single genetic aberrations. These conditions often fall within the orphan disease space and GW is working with investigators to gain clinical experience in the use of different cannabinoids with the aim to commence clinical trials in 2016.

Glioma

GW is testing its product candidate GWP42002:GWP42003 in the treatment of recurrent glioblastoma multiforme, or GBM, a particularly aggressive brain tumor which is considered a rare disease by the FDA and the EMA. In pre-clinical models, GW has shown these cannabinoids used together to be orally active in the treatment of glioma xenografts and have shown tumor response to be positively associated with tissue levels of cannabinoids.

GW has commenced a Phase 1b clinical trial in patients with recurrent GBM. The first phase of this trial, which is now complete, was an open-label safety evaluation of GWP42002:GWP42003 in combination with dose-intense temozolomide. Safety data from this initial patient cohort was assessed by the independent safety monitoring board and their approval given to proceed into a 20 patient placebo-controlled phase. This second phase is now fully recruited and data expected in mid-2016.

Other Pipeline Programs

Sativex in Cancer Pain

Sativex is an oromucosal spray consisting of a formulated extract of the cannabis sativa plant that contains the principal cannabinoids delta-9-tetrahydrocannabinol, or THC, and CBD. GW is currently evaluating Sativex in a Phase 3 program to treat persistent pain in people with advanced cancer who experience inadequate pain relief from optimized chronic opioid therapy, the current standard of care.

In January 2015, GW announced top-line results from the first of three Sativex pivotal Phase 3 cancer pain trials. In this first trial, Sativex (as adjunctive treatment to optimized chronic opioid therapy) was well tolerated but did not meet the primary endpoint of demonstrating a statistically significant difference from placebo. GW has two additional pivotal Phase 3 trials ongoing which are due to report top-line data in the second half of 2015. Since the two ongoing Phase 3 trials are studying the same patient population and use the same endpoints, GW considers that the probability of success in these trials is low.

The costs of the Phase 3 cancer pain program are fully funded by Otsuka Pharmaceutical Co. Ltd, who hold exclusive rights to commercialize Sativex in the U.S.

Sativex in Multiple Sclerosis (MS)

Sativex is currently 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 (“SPA”) has been submitted to the FDA for a proposed single Phase 3 study.

Type-2 Diabetes

GW is testing its product candidate GWP42004 in the treatment of type-2 diabetes. GWP42004 is an orally administered product which features plant-derived tetrahydrocannabivarin (THCV) as its active ingredient. THCV is distinct from THC and does not share its intoxicating psychoactive effects. Pre-clinical models have shown evidence of pancreatic islet cell protection, and an earlier small scale proof of concept study have shown GWP42004 to have promising effects on glucose and insulin status in patients with Type 2 diabetes. The ongoing study will compare the efficacy, safety and tolerability of three doses of GWP42004 with placebo in a total of 200 patients and is expected to report data in 2016. GW believes that if the Phase 2 study confirms the earlier Phase 2 findings, GWP42004 would have the potential to offer a novel orally-administered treatment option in this large potential market.

Pre-clinical developments

In addition to GW’s extensive in-house research organization, the Company has established a global network of leading scientists in the cannabionoid field including 34 academic institutions in nine countries. GW’s proprietary cannabinoid product platform allows the Company to discover, develop and commercialize additional novel first-in-class cannabinoid products across a broad range therapeutic areas. Some of the more advanced programs include:

• The use of CBD in Duchenne muscular dystrophy (DMD), the most common inherited lethal childhood orphan disease in the world, where the discovery of a “membrane stress hypothesis” leads researchers to conclude that muscle cells respond positively to CBD by increasing metabolic output and improving mitochondrial function,
• In Glioma, research suggests that a combination of cannabinoids with other anticancer agents can eliminate GICs (Glioma Initiating Cells) which can cause recurrence of tumors after surgery. These findings are significant as GICs are resistant to most anticancer therapies and therefore reduce the apparent effectiveness of conventional brain cancer therapies,
• The use of the cannabinoid CBG in the treatment of chemotherapy-induced cachexia where pre-clinical data supports a multi-modal action that includes a protective effect on overall loss of muscle mass, stimulation of feeding, and a normalized metabolic profile,
• In ovarian cancer, pre-clinical research has demonstrated the ability for CBD to act as a cytotoxic medicine, killing cancer cells or stopping them from multiplying, possibly offering a new, more tollerable form of chemotherapy.

GW Investor Conference Activity

GW expects to present at the following investor conferences in September 2015: Morgan Stanley Global Healthcare Conference in New York City and the Bank of America Merrill Lynch Healthcare Conference in London.

About GW Pharmaceuticals plc

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. GW is also advancing an orphan drug program in the field of childhood epilepsy with a focus on Epidiolex^(R), which is in Phase 3 clinical development for the treatment of Dravet syndrome and the treatment of Lennox-Gastaut syndrome. GW has a deep pipeline of additional cannabinoid product candidates which includesSativex in Phase 3 clinical development as a potential treatment of pain associated with advanced cancer, as well as compounds in Phase 1 and 2 clinical development for glioma, 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 in this news release 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.

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