X0306 4 2019-05-15 0 0001351288 GW PHARMACEUTICALS PLC GWPH 0001754122 Knappertz Volker SOVEREIGN HOUSE, VISION PARK, HISTON CAMBRIDGE X0 CB24 9BZ UNITED KINGDOM 0 1 0 0 Chief Medical Officer Ordinary Shares 2019-05-15 4 S 0 4296 14.63 D 77940 D Ordinary Shares 2020-06-17 4 S 0 18000 10.35 D 59940 D The sales reported were effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on March 14, 2019. Inadvertent late filing. Represented by American Depositary Shares of the Issuer ("ADSs"). Each ADS represents twelve ordinary shares of the Issuer. The price reported in Column 4 is a price per ordinary share converted from price per ADS. Due to an administrative error, the Reporting Person's Form 3 filed with the SEC on October 1, 2018 overstated the Reporting Person's ownership of the Issuer's ordinary shares by 4,440 shares (370 ADSs). These shares have been excluded from Column 5. Also reflects an adjustment to total holdings to exclude twelve shares incorrectly included in prior reports. The sales reported were effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on May 18, 2020. /s/ Volker Knappertz 2020-06-19