Spero Therapeutics, Inc. Loss Submission Form

(i) the data submitted in support of the New Drug Application (“NDA”) for the Company’s product candidate, Tebipenem HBr, were insufficient to obtain approval from the U.S. Food and Drug Administration (“FDA”); (ii) accordingly, it was unlikely that the FDA would approve the Tebipenem HBr NDA in its current form; (iii) the foregoing would necessitate a significant workforce reduction and restructuring of Spero’s operations; and (iv) as a result, the Company’s public statements were materially false and misleading at all relevant times.