1. Organization and Principal Activities

Description of Business

Sutro Biopharma, Inc. (the “Company”) is a clinical stage drug discovery, development and manufacturing company focused on leveraging its integrated cell-free protein synthesis and site-specific conjugation platform, XpressCF+™, to create a broad variety of optimally designed, next-generation protein therapeutics for cancer and autoimmune disorders. The Company was incorporated on April 21, 2003, and was formerly known as Fundamental Applied Biology, Inc. The Company is headquartered in South San Francisco, California.

The Company operates in one business segment, the development of biopharmaceutical products.

Liquidity

The Company has incurred significant losses and has negative cash flows from operations. As of March 31, 2019, there was an accumulated deficit of $154.3 million. Management expects to continue to incur additional substantial losses in the foreseeable future as a result of the Company’s research and development activities and costs to operate as a public company.

As of March 31, 2019, the Company had unrestricted cash, cash equivalents and marketable securities of $184.3 million, which are available to fund future operations. The Company will need to raise additional capital to support the completion of its research and development activities and its operations.

The Company believes that its unrestricted cash, cash equivalents and marketable securities as of March 31, 2019 will be sufficient for the Company to continue as a going concern for at least one year from the issuance date of its unaudited interim condensed financial statements.