X0306 4/A 2019-04-01 2019-04-03 0 0001755237 Cyclerion Therapeutics, Inc. CYCN 0001478244 Currie Mark G C/O CYCLERION THERAPEUTICS, INC. 301 BINNEY STREET CAMBRIDGE MA 02142 0 1 0 0 President Employee Stock Option (Right to Buy) 12.24 2019-04-01 4 A 0 37279 0.00 A 2021-02-01 Common Stock 37279 37279 D Employee Stock Option (Right to Buy) 16.21 2019-04-01 4 A 0 17490 0.00 A 2022-02-01 Common Stock 17490 17490 D Employee Stock Option (Right to Buy) 14.40 2019-04-01 4 A 0 27772 0.00 A 2023-02-01 Common Stock 27772 27772 D Employee Stock Option (Right to Buy) 17.20 2019-04-01 4 A 0 2500 0.00 A 2025-03-01 Common Stock 2500 2500 D Employee Stock Option (Right to Buy) 11.28 2019-04-01 4 A 0 50794 0.00 A 2026-03-01 Common Stock 50794 50794 D Employee Stock Option (Right to Buy) 18.47 2019-04-01 4 A 0 113413 0.00 A 2027-02-27 Common Stock 113413 113413 D Employee Stock Option (Right to Buy) 16.02 2019-04-01 4 A 0 140984 0.00 A 2028-02-21 Common Stock 140984 140984 D Employee Stock Option (Right to Buy) 14.21 2019-04-01 4 A 0 514698 0.00 A 2029-01-29 Common Stock 514698 514698 D This report has been amended to correct the exercise price of the stock options that were originally issued by Ironwood Pharmaceuticals, Inc. ("Ironwood") as a result of the spin-off of the Issuer from Ironwood, effective on April 1, 2019 ("the Separation"). This option, granted as an annual performance award, is presently exercisable in full. This report has been amended to reflect the number of options that were assumed by the Issuer under its applicable mirror equity plan as a result of the Separation. This footnote has been amended to reflect the number of unvested options that were assumed by the Issuer under its applicable mirror equity plan as a result of the Separation. This option to purchase 25,208 shares vests in equal installments upon achievement of certain regulatory and commercial milestones. The option has vested as to 2,500 shares as of the date hereof. The option, granted as an annual performance award, vests as to 2.08333% of the shares of Common Stock on each monthly anniversary of January 1, 2016. The option, granted as an annual performance award, vests as to 2.08333% of the shares of Common Stock on each monthly anniversary of January 1, 2017. The option, granted as an annual performance award, vests as to 2.08333% of the shares of Common Stock on each monthly anniversary of January 1, 2018. The option, granted as an annual performance award, vests as to 2.08333% of the shares of Common Stock on each monthly anniversary of January 1, 2019. /s/ Larry Miller, Attorney-in-Fact 2019-09-20