On April 2, 2024, Ankur Dhingra, the principal financial officer and principal accounting officer of Summit Therapeutics Inc. (the Company), resigned as Chief Financial Officer of the Company. Mr. Dhingra?s resignation was not due to any disagreement with the Company relating to its operations, policies or practices. In order to replace Mr. Dhingra, contemporaneously with Mr. Dhingra?s resignation, the Company appointed its Chief Operating Officer Manmeet Soni to the office of Chief Financial Officer, in which capacity he will serve as the Company?s principal financial officer, in addition to his continuing service as Chief Operating Officer.

Mr. Soni, age 46, has served as Chief Operating Officer since October 2023 and as a member of the Company?s board of directors (the ?Board?) since December 2019. Mr. Soni previously served as the President, Chief Operating Officer and Chief Financial Officer of Reata Pharmaceuticals Inc., a role he held from February 2022 through September 2023, after initially joining Reata Pharmaceuticals as an executive officer in August 2019. Prior to joining Reata Pharmaceuticals, Mr. Soni was the Senior Vice President and Chief Financial Officer of Alnylam Pharmaceuticals Inc. from May 2017 to August 2019.

Mr. Soni has served as a member of the board of directors of Pulse Biosciences Inc. since November 2017 and previously served as a member of the board of directors of Arena Pharmaceuticals Inc. from December 2018 to June 2021. Mr. Soni is a Certified Public Accountant and Chartered Accountant (India).