News & Events

and in the press release furnished as Exhibit 99.1 hereto shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or otherwise subject to the liabilities of that Section or Sections 11 and 12(a)(2) of the Securities Act of 1933, as amended, or incorporated by reference in any filing with the U.S. Securities and Exchange Commission made by the Company, whether made before or after the date hereof, regardless of any general incorporation langua…

and in the press release furnished as Exhibit 99.1 hereto shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or otherwise subject to the liabilities of that Section or Sections 11 and 12(a)(2) of the Securities Act of 1933, as amended, or incorporated by reference in any filing with the U.S. Securities and Exchange Commission made by the Company, whether made before or after the date hereof, regardless of any general incorporation langua…

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers. (b) On January 30, 2026, Ankit Mahadevia, MD notified the Board of Directors (the “Board”) of Spero Therapeutics, Inc. (the “Company”) of his intention to resign from the Board, including from his service on the Development Committee of the Board and from all officer and director positions he holds with any and all subsidiaries of the Company, effe…

Other Events. On December 19, 2025, Spero Therapeutics, Inc. (the “Company”) announced that its tebipenem HBr development partner, GlaxoSmithKline Intellectual Property (No. 3) Limited (“GSK”), filed a New Drug Application (“NDA”) resubmission to the U.S. Food and Drug Administration for tebipenem HBr, an investigational oral carbapenem antibiotic being developed for the treatment of complicated urinary tract infections (cUTI), including pyelonephritis. The NDA submission triggers a $25 milli…

and in the press release furnished as Exhibit 99.1 hereto shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that Section or Sections 11 and 12(a)(2) of the Securities Act of 1933, as amended (the “Securities Act”), or incorporated by reference in any filing with the U.S. Securities and Exchange Commission made by the Company, whether made before or after the date hereof, re…

and in the press release furnished as Exhibit 99.1 hereto shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that Section or Sections 11 and 12(a)(2) of the Securities Act of 1933, as amended (the “Securities Act”), nor shall it be deemed incorporated by reference in any filing under the Securities Act or the Exchange Act, except as expressly set forth by specific reference…

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers At the 2025 Annual Meeting of Stockholders (the “Annual Meeting”) of Spero Therapeutics, Inc. (the “Company”) held on June 12, 2025, the Company’s stockholders approved an amendment to the Company’s 2017 Stock Incentive Plan, as amended (the “2017 Plan”) to increase the total number of shares of the Company’s common stock authorized for issuance und…

Other Events. On May 28, 2025, the Company along with its development partner GSK plc (“GSK”) announced that the pivotal Phase 3 PIVOT-PO trial evaluating tebipenem HBr, an investigational oral treatment for cUTIs, including pyelonephritis, met its primary endpoint and will stop early for efficacy. The decision follows a recommendation from an Independent Data Monitoring Committee (“IDMC”) that completed a pre-specified interim analysis of data from 1,690 patients enrolled in the trial. The P…

and in the press release furnished as Exhibit 99.1 hereto shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or otherwise subject to the liabilities of that Section or Sections 11 and 12(a)(2) of the Securities Act of 1933, as amended, or incorporated by reference in any filing with the U.S. Securities and Exchange Commission made by the Company, whether made before or after the date hereof, regardless of any general incorporation langua…

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers. Appointment of Esther Rajavelu as President and Chief Executive Officer and Nomination for Election to the Board of Directors On April 28, 2025, Spero Therapeutics, Inc. (the “Company”) announced that effective as of May 2, 2025 (the “Effective Date”), Esther Rajavelu will serve as the Company’s President and Chief Executive Officer. Since January…

and in the press release furnished as Exhibit 99.1 hereto shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or otherwise subject to the liabilities of that Section or Sections 11 and 12(a)(2) of the Securities Act of 1933, as amended, or incorporated by reference in any filing with the U.S. Securities and Exchange Commission made by the Company, whether made before or after the date hereof, regardless of any general incorporation langua…

Notice of Delisting or Failure to Satisfy a Continued Listing Rule or Standard; Transfer of Listing. On February 25, 2025, Spero Therapeutics, Inc., a Delaware corporation (the “Company”) received a deficiency letter (the “Deficiency Letter”) from the Listing Qualifications Department of the Nasdaq Stock Market, LLC (“Nasdaq”) notifying the Company that, for the preceding 30 consecutive trading days, the closing bid price of its common stock was below the $1.00 per share minimum bid price req…