Spero Therapeutics, Inc., a multi-asset, clinical-stage biopharmaceutical company focused on identifying, developing and commercializing novel treatments for multi-drug resistant bacterial infections, today announced that it has commenced an initial public offering of 5,000,000 shares of its common stock. Spero has also granted the underwriters a 30-day option to purchase an additional 750,000 shares of its common stock. The price range for the initial public offering is currently estimated to be between $14.00 and $16.00 per share. Spero has applied to list its common stock on The NASDAQ Global Market under the symbol “SPRO.”

BofA Merrill Lynch, Cowen and Company, LLC and Stifel are serving as joint book-running managers for the proposed offering. Oppenheimer & Co. is acting as a co-manager for the proposed offering.

About Spero

Spero Therapeutics is a multi-asset, clinical-stage biopharmaceutical company focused on identifying, developing and commercializing novel treatments for multi-drug resistant bacterial infections.