Spero Therapeutics Inc

Two putative class action lawsuits were filed against us and certain of our officers in the United States District Court for the Eastern District of New York, one captioned Richard S. Germond v. Spero Therapeutics, Inc., Ankit Mahadevia, and Satyavrat Shukla, Case No. 1:22-cv-03125, filed on May 26, 2022, and the other captioned Kashif Memon v. Spero Therapeutics, Inc., Ankit Mahadevia, and Satyavrat Shukla Case No. 1:22-cv-04154, filed on July 15, 2022. The parties moved to consolidate the two complaints on July 22, 2022, which were ordered consolidated on August 5, 2022 (“Consolidated Putative Class Action”). The parties filed an Amended Complaint on December 5, 2022, purported to be brought on behalf of stockholders who purchased our common stock from September 8, 2020 through May 2, 2022. The Amended Complaint generally alleges that we and certain of our current and former officers violated Sections 10(b) and/or 20(a) of the Exchange Act and Rule 10b-5 promulgated thereunder by making allegedly false and/or misleading statements concerning the NDA for tebipenem HBr in an effort to lead investors to believe that the drug would receive approval from the FDA. Plaintiffs seek unspecified damages, interest, attorneys’ fees, and other costs. We filed a fully-briefed Motion to Dismiss on June 21, 2023. The Court has not yet ruled on the Motion.

A stockholder derivative action was filed against us, as nominal defendant, and certain of our officers in the United States District Court for the District of Delaware, captioned Marti v. Mahadevia, et al., Case. No. 1:23-cv-01133-RGA (the “Derivative Complaint”), on October 11, 2023. The plaintiffs both purport to be current stockholders, and the allegations are primarily the same as those made in the Consolidated Putative Class Action. The Derivative Complaint was transferred to the Eastern District of New York on November 13, 2023, and stayed by party agreement pending outcome of the Motion to Dismiss the class action on November 20, 2023. A second stockholder derivative action was filed against us, as nominal defendant, and certain of our officers in the Supreme Court of the State of New York, Kings County, captioned Heil v. Mahadevia, et al., Case. No. 505153/2024 (the “Second Derivative Complaint”), on February 21, 2024. The Second Derivative Complaint makes primarily the same allegations as the First Derivative Complaint, and the Consolidated Putative Class Action

We deny any allegations of wrongdoing and intend to vigorously defend against these lawsuits. However, there is no assurance that we will be successful in our defense or that insurance will be available or adequate to fund any settlement or judgment or the litigation costs of these actions. Moreover, we are unable to predict the outcomes or reasonably estimate a range of possible loss at this time.

Additional lawsuits against us and certain of our officers or directors may be filed in the future. If additional similar complaints are filed, absent new or different allegations that are material, we will not necessarily announce such additional filings.