Spero Therapeutics Inc

(a)Chief Medical Officer and Director Transitions

Dr. Kamal Hamed, Chief Medical Officer, is departing the Company effective as of August 29, 2024. The Company has an ongoing executive search for a successor to Dr. Hamed and expects to enter into a consulting agreement with Dr. Hamed for transition services. In connection with his departure, Dr. Hamed shall also be entitled to the severance benefits described in his employment agreement, subject to entering into a separation agreement to implement the foregoing.

Additionally, in connection with the foregoing, the Company appointed Board member, John C. Pottage, Jr., M.D., as its special advisor and entered into a consulting agreement with Dr. Pottage. Dr. Pottage has significant expertise in drug development and regulatory matters, having over 20 years in the biopharma industry, including previously serving as Senior Vice President and Chief Scientific and Medical Officer of ViiV Healthcare, and currently being the Chair of the Company’s Development Committee of its Board of Directors. While Dr. Pottage serves in his role as special advisor, the Company’s Board of Directors has replaced him on the Audit Committee with Milind Deshpande, who satisfies all applicable independence and other requirements to join the Audit Committee.

(c) Director and Officer Trading Arrangements

None of our directors or officers adopted or terminated a Rule 10b5-1 trading arrangement or a non-Rule 10b5-1 trading arrangement (as such terms are defined in Items 408(a) and 408(c) of Regulation S-K, respectively) during the quarterly period covered by this report.