Pharmaceuticals plc (GWPH), a world leader in the science, development, and commercialization of cannabinoid prescription medicines, today announces financial results for the fourth quarter and full-year ended December 31, 2019.

“2019 was an exceptional and transformative year for GW, led by the successful launch of Epidiolex in the US and approval in Europe. The positive impact this medicine has had on thousands of patients and their families provides a compelling foundation for continued growth in 2020,” said Justin Gover, GW’s Chief Executive Officer. “We also expect 2020 to be an important year for our growing and developing product pipeline beyond Epidiolex as we build on our world leadership in cannabinoid science. We are focused on advancing nabiximols in the US in several indications and clinical programs with other potential products whilst continuing to bring Epidiolex to more patients in the US and Europe.”

OPERATIONAL HIGHLIGHTS

Significant progress with Epidiolex (cannabidiol) Total net product sales of Epidiolex of $104.5 million for the fourth quarter and $296.4 million for the full year U.S. commercial update 2020 focus on broadening prescriber base, expanding payer coverage, entering long term care segment, and expected launch of TSC indication European launch underway German commercial launch in Q4 2019 Secured positive NICE recommendation in the UK with commercial launch in Q1 2020 Commercial launches in France, Spain and Italy expected later this year, following pricing and reimbursement Clinical progress with further indications – broadening addressable market Tuberous Sclerosis Complex (TSC) sNDA filed with FDA earlier this month and MAA submission to EMA expected in Q1 2020 Phase 3 trial in Rett Syndrome recruiting Several new formulations of CBD advancing into additional Phase 1 studies in 2020, including modified oral solution, and capsule Improved intellectual property rights and exclusivity In addition to orphan exclusivity, 9 granted patents listed in “Orange Book” and align directly with Epidiolex FDA label with expiry dates to 2035 Epidiolex composition patent application recently published 2 new allowed patents broadly covering use in LGS and Dravet syndrome Additional patent applications under review, including patents related to the use of Epidiolex in TSC and other indications

Pipeline progress Nabiximols (Sativex ® outside of the US) Multiple Sclerosis spasticity -3 positive Phase 3 trials completed in Europe US pivotal clinical program expected to commence in Q2 2020 to augment existing data package Spinal cord injury spasticity – clinical program expected to commence in H2 2020 PTSD – clinical program expected to commence in H2 2020 Schizophrenia (GWP42003) Positive Phase 2a trial published and Phase 2b trial expected to commence H1 2020 CBDV in autism 30-patient open label study in autism underway. Initial data expected in 2020. Investigator-led 100 patient placebo-controlled trial in autism underway Open label study in Rett syndrome and seizures underway Neonatal Hypoxic-Ischemic Encephalopathy (NHIE) intravenous CBD program Phase 1b safety study in patients underway Orphan Drug and Fast Track Designations granted from FDA and EMA



FINANCIAL HIGHLIGHTS

Total revenue for the quarter ended December 31, 2019 was $109.1 million compared to $6.7 million for the quarter ended December 31, 2018

Net loss for the quarter ended December 31, 2019 was $24.9 million compared to a net loss of $71.9 million for the quarter ended December 31, 2018

Cash and cash equivalents at December 31, 2019 were $536.9 million compared to $591.5 million as of December 31, 2018

Conference Call and Webcast Information

GW Pharmaceuticals will host a conference call and webcast today at 4:30 pm EST. To participate in the conference call, please dial 877-407-8133 (toll free from the U.S. and Canada) 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 http://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 90 days. Replay Numbers: (toll free):1-877-481-4010 or 919-882-2331 (international). For both dial-in numbers please use conference Replay ID: 33178.

About GW Pharmaceuticals plc and Greenwich Biosciences, Inc.

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. The Company’s lead product, EPIDIOLEX® (cannabidiol) oral solution CV, is commercialized in the U.S. by its U.S. subsidiary Greenwich Biosciences for the treatment of seizures associated with Lennox-Gastaut syndrome or Dravet syndrome in patients two years of age or older. This product has received approval in the European Union under the tradename EPIDYOLEX®. The Company has submitted a supplemental New Drug Application to the U.S. Food and Drug Administration (FDA) to expand the indication for Epidiolex to include seizures associated with Tuberous Sclerosis Complex, for which it has reported positive Phase 3 data, and is carrying out a Phase 3 trial in Rett syndrome. The Company has a deep pipeline of additional cannabinoid product candidates, in particular nabiximols, for which the Company is advancing multiple late-stage clinical programs in order to seek FDA approval in the treatment of spasticity associated with multiple sclerosis and spinal cord injury, as well as for the treatment of PTSD. The Company has additional cannabinoid product candidates in Phase 2 trials for autism 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 timing and outcomes of regulatory or intellectual property decisions, the relevance of GW products commercially available and in development, the clinical benefits of EPIDIOLEX®/EPIDYOLEX® (cannabidiol) oral solution CV and Sativex® (nabiximols), and the safety profile and commercial potential of both medicines. 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 and uncertainties related to the regulatory process, and the acceptance of EPIDIOLEX®/EPIDYOLEX®, Sativex® 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.