On January 30, 2023, the Board of Directors of Spero Therapeutics, Inc. appointed Timothy Keutzer as the company's Chief Operating Officer, effective as of February 1, 2023 (Effective Date). Mr. Keutzer, age 55, has served as the Company's Chief Development Officer since June 2019 and previously served as the Company's Senior Vice President, Development from September 2015 to June 2019. He has over 20 years' experience in the pharmaceutical industry, spanning multiple functional and therapeutic areas.

Prior to joining the Company, Mr. Keutzer served in various roles at Cubist Pharmaceuticals, Inc. (“Cubist”), including as Vice President of Program and Portfolio Management from May 2014 to July 2015. At Cubist, Mr. Keutzer was the program leader for ceftolozane/tazobactam, which progressed rapidly from Phase 1 to Phase 3, and was approved by the U.S. Food and Drug Administration in December 2014. Prior to that role, Mr. Keutzer also led several of Cubist's in-licensed development programs and led the commercial supply chain for Cubicin.

His experience before Cubist spans multiple drug classes and includes preclinical PK/PD and clinical operations at Genetics Institute, as well as global strategic marketing and program management at Wyeth Pharmaceuticals Inc. Mr. Keutzer began his career in contract toxicology labs. Mr. Keutzer earned his bachelor's degree from the University of Kentucky.