X0306 4/A 2019-04-01 2019-04-03 0 0001755237 Cyclerion Therapeutics, Inc. CYCN 0001723846 Huyett William C/O CYCLERION THERAPEUTICS, INC. 301 BINNEY STREET CAMBRIDGE MA 02142 0 1 0 0 Chief Financial Officer Common Stock 2019-04-01 4 A 0 38320 0.00 A 38320 D Common Stock 2019-04-01 4 A 0 39172 0.00 A 78898 D Employee Stock Option (Right to Buy) 16.82 2019-04-01 4 A 0 221312 0.00 A 2028-01-02 Common Stock 221312 221312 D Employee Stock Option (Right to Buy) 14.21 2019-04-01 4 A 0 221964 0.00 A 2029-01-29 Common Stock 221964 221964 D In connection with the separation of Cyclerion Therapeutics, Inc. ("Cyclerion") from Ironwood Pharmaceuticals Inc. ("Ironwood") effective April 1, 2019 (the "Separation"), the reporting person received a grant of 38,320 restricted stock units, each representing the right to receive a share of Cyclerion common stock, as a result of the adjustment of existing Ironwood restricted stock units held by the reporting person prior to the Separation. The restricted stock unit award, granted as an annual performance award, vests as to 25% of the shares of common stock on the approximate anniversary of the grant. 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. In connection with the Separation, the reporting person received a grant of 39,172 restricted stock units, each representing the right to receive a share of Cyclerion common stock, as a result of the adjustment of existing Ironwood restricted stock units held by the reporting person prior to the Separation. The restricted stock unit award, granted as an annual performance award, vests as to 25% of the shares of common stock on the approximate anniversary of the grant. This report has been amended to reflect the number of shares received in a pro rata distribution as a result of the Separation. This report has been amended to correct the exercise price of the stock options that were originally issued by Ironwood in connection with the Separation. The option, granted as a new hire award, vested as to 25% of the shares of common stock on December 15, 2018, and 2.08333% of the shares of common stock vest each month thereafter for the next 36 months. 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