- Total revenue of $109.1 million for the fourth quarter and $311.3 million for the full year -

- Total Epidiolex® net product sales of $104.5 million for the fourth quarter and $296.4 million for the first full year of sales -

- Conference call today at 4:30 p.m. EST -

LONDON and CARLSBAD, Calif., Feb. 25, 2020 (GLOBE NEWSWIRE) -- GW Pharmaceuticals plc (Nasdaq: 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.

Enquiries:

GW Pharmaceuticals plc Stephen Schultz, VP Investor Relations 917 280 2424 / 401 500 6570 U.S. Media Enquiries:

Sam Brown Inc. Healthcare Communications Christy Curran

Mike Beyer 615 414 8668

312 961 2502 Ex-U.S. media enquiries Ben Atwell, FTI Consulting +44 (0)203 727 1000

GW PHARMACEUTICALS PLC

CONDENSED CONSOLIDATED BALANCE SHEETS

(in thousands, except share data)

(unaudited)

December 31, December 31, 2019 2018 Assets Cash and cash equivalents $ 536,933 $ 591,497 Accounts receivable, net 48,883 4,192 Inventory 85,528 33,030 Prepaid expenses and other current assets 28,292 17,903 Total current assets 699,636 646,622 Property, plant, and equipment, net 127,765 90,832 Operating lease assets 24,916 — Goodwill 6,959 6,959 Deferred tax assets 18,123 8,720 Other assets 4,850 2,935 Total assets $ 882,249 $ 756,068 Liabilities and stockholders’ equity Accounts payable $ 9,990 $ 9,796 Accrued liabilities 99,374 52,477 Current tax liabilities 437 2,384 Other current liabilities 7,760 1,559 Total current liabilities 117,561 66,216 Long-term liabilities: Finance lease liabilities 5,573 5,690 Operating lease liabilities 21,650 — Other liabilities 11,431 10,082 Total long-term liabilities 38,654 15,772 Total liabilities 156,215 81,988 Commitments and contingencies Stockholders’ equity: Ordinary shares par value £0.001; 371,068,436 and 366,616,688 shares

outstanding as of December 31, 2019 and 2018, respectively 570 564 Additional paid-in capital 1,632,046 1,581,144 Accumulated deficit (837,959 ) (828,940 ) Accumulated other comprehensive loss (68,623 ) (78,688 ) Total stockholders’ equity 726,034 674,080 Total liabilities and stockholders’ equity $ 882,249 $ 756,068

GW PHARMACEUTICALS PLC

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS

(in thousands, except per share amounts)

(unaudited)

Three Months Ended December 31, Year Ended December 31, 2019 2018 2019 2018 Revenues Product net sales $ 109,019 $ 6,617 $ 310,331 $ 14,866 Other revenue 57 37 1,001 533 Total revenues 109,076 6,654 311,332 15,399 Operating expenses Cost of product sales 7,298 1,829 27,199 6,644 Research and development 43,535 29,086 142,678 146,627 Selling, general and administrative 78,351 49,083 259,880 165,727 Total operating expenses 129,184 79,998 429,757 318,998 Loss from operations (20,108 ) (73,344 ) (118,425 ) (303,599 ) Interest income 1,818 2,449 8,464 5,490 Interest expense (282 ) (295 ) (1,087 ) (1,230 ) Other income — — 104,117 — Foreign exchange loss (5,073 ) (982 ) (2,272 ) (6,105 ) Loss before income taxes (23,645 ) (72,172 ) (9,203 ) (305,444 ) Income tax expense (benefit) 1,301 (266 ) (184 ) (187 ) Net loss $ (24,946 ) $ (71,906 ) $ (9,019 ) $ (305,257 ) Net loss per share: Basic $ (0.07 ) $ (0.20 ) $ (0.02 ) $ (0.88 ) Diluted $ (0.07 ) $ (0.20 ) $ (0.02 ) $ (0.88 ) Weighted average shares outstanding: Basic 372,447 366,458 371,580 347,123 Diluted 372,447 366,458 371,580 347,123

GW PHARMACEUTICALS PLC

CONSOLIDATED STATEMENTS OF CASH FLOWS

(in thousands)

(unaudited)

Year Ended December 31, 2019 2018 Cash flows from operating activities Net loss $ (9,019 ) $ (305,257 ) Adjustments to reconcile net loss to net cash used in

operating activities: Foreign exchange loss 2,709 5,839 Stock-based compensation 48,030 35,718 Depreciation and amortization 9,240 9,661 Deferred income taxes (9,698 ) (430 ) Gain from sale of priority review voucher (104,117 ) — Other 39 233 Changes in operating assets and liabilities: Accounts receivable, net (44,623 ) (2,706 ) Inventory (51,125 ) (28,484 ) Prepaid expenses and other current assets (9,831 ) 11,370 Other assets 3,888 (445 ) Accounts payable 805 2,829 Current tax liabilities (963 ) (3,966 ) Accrued liabilities 43,110 19,445 Other liabilities (1,914 ) 1,423 Net cash used in operating activities (123,469 ) (254,770 ) Cash flows from investing activities Proceeds from sale of priority review voucher 104,117 — Additions to property, plant and equipment (40,386 ) (42,301 ) Additions to capitalized software (2,102 ) (1,112 ) Proceeds from disposal of property, plant and equipment — 517 Net cash provided by (used in) investing activities 61,629 (42,896 ) Cash flows from financing activities Proceeds from issuance of ordinary shares, net of

issuance costs — 324,637 Proceeds from exercise of stock options 2,878 620 Payments on finance leases (389 ) (251 ) Payments on landlord financing obligation (543 ) (527 ) Net cash provided by (used in) financing activities 1,946 324,479 Effect of exchange rate changes on cash 5,330 5,457 Net increase (decrease) in cash and cash equivalents (54,564 ) 32,270 Cash and cash equivalents at beginning of period 591,497 559,227 Cash and cash equivalents at end of period $ 536,933 $ 591,497



