Sutro Biopharma, Inc. (Nasdaq: STRO), a clinical-stage drug discovery, development and manufacturing company focused on the application of precise protein engineering and rational design to create next-generation cancer and autoimmune therapeutics, today announced a proposed underwritten public offering in which it intends to offer and sell 5,000,000 shares of its common stock. In addition, Sutro intends to grant the underwriters a 30-day option to purchase up to an additional 750,000 shares of common stock offered in the public offering. All of the shares of common stock are being offered by Sutro. The offering is subject to market and other conditions, and there can be no assurance as to whether or when the offering may be completed, or as to the actual size or terms of the offering.

Cowen, Piper Sandler and Wells Fargo Securities are acting as joint book-running managers in the offering. Wedbush PacGrow and JMP Securities are acting as co-managers for the offering.

Sutro intends to use the net proceeds from the proposed offering, together with its existing cash, cash equivalents and marketable securities, to fund the continued clinical development of STRO-001 and STRO-002 and the remainder to fund the further development of its technology platform, including manufacturing, to broaden its pipeline of product candidates, and for working capital and general corporate purposes.