X0306 4 2022-06-01 0 0001446847 IRONWOOD PHARMACEUTICALS INC IRWD 0001361754 DENNER ALEXANDER J C/O IRONWOOD PHARMACEUTICALS, INC. 100 SUMMER STREET, SUITE 2300 BOSTON MA 02110 1 0 1 0 0001577524 Sarissa Capital Management LP 660 STEAMBOAT ROAD 3RD FLOOR GREENWICH CT 06830 0 0 1 0 Class A Common Stock 2022-06-01 4 A 0 21571 0.00 A 88145 D Class A Common Stock 16390000 I See footnote The restricted stock, granted pursuant to the Director Compensation Policy effective May 2019, vests in full on the date immediately preceding the date of the annual meeting of stockholders for the next calendar year. Consists of shares that are held by Sarissa Capital Management LP ("Sarissa Capital") or by the funds and other investment vehicles (the "Sarissa Funds") for which Sarissa Capital serves as investment advisor. Dr. Denner is the Chief Investment Officer of Sarissa Capital and the managing member, general partner or other control party of the Sarissa Funds. By virtue of the foregoing, Dr. Denner may be deemed to indirectly beneficially own the shares that these funds directly beneficially own. Each of Sarissa Capital, the Sarissa Funds and Dr. Denner disclaims beneficial ownership of these shares except, in each case, to the extent of their pecuniary interest therein. SARISSA CAPITAL MANAGEMENT LP, By: /s/ Mark DiPaolo, Name: Mark DiPaolo, Title: Senior Partner, General Counsel 2022-06-03 /s/ Alexander Denner 2022-06-03