Sutro Biopharma Inc (NASDAQ: STRO) is a clinical-stage biopharmaceutical company that develops antibody-drug conjugates and other protein therapeutics using its cell-free protein synthesis platform. The company generates revenue primarily through collaboration agreements, collecting upfront payments, research funding, and milestone payments from partners including Bristol Myers Squibb, Merck, Astellas, Vaxcyte, Ipsen, EMD Serono, BioNova, and Tasly. Additional funding has come from public equity offerings, an at-the-market facility with Jefferies LLC under an Open Market Sales Agreement dated April 2, 2021, debt financing, sale of Vaxcyte common stock holdings, and a royalty monetization agreement with Blackstone. Sutro had 137 full-time employees as of December 31, 2025 and is headquartered in San Carlos, California. In March 2025, the Board approved a strategic portfolio review with planned workforce reductions to reduce operating costs and extend cash runway. The company has not yet generated product revenue and remains pre-commercial.

Revenue model

Collaboration agreements providing upfront fees, research funding, and development milestone payments, recognized under ASC 606 when performance obligations are satisfied. Supplemental funding from equity offerings, debt financing, Vaxcyte stock sales, and a royalty monetization agreement with Blackstone.

Products and services

Cell-free protein synthesis platform for antibody-drug conjugate and protein therapeutic development. Research and development services provided to pharmaceutical collaborators including BMS, Merck, Astellas, Vaxcyte, Ipsen, EMD Serono, BioNova, and Tasly. No commercial products as of the 10-K filed 2026-03-23.

Customers and end markets

Pharmaceutical and biopharmaceutical companies as collaboration partners, including Bristol Myers Squibb, Merck, Astellas, Vaxcyte, Ipsen, EMD Serono, BioNova, and Tasly. End market is oncology and other disease areas addressed through antibody-drug conjugates and engineered proteins.

Value-chain role

Drug discovery and development platform provider. Sutro conducts internal research and development and manufactures proteins using its cell-free synthesis technology, licensing or collaborating with larger pharmaceutical partners for downstream clinical development and commercialization.

Geographic exposure

Operations based in San Carlos, California. No geographic revenue breakdown disclosed in the excerpts from the 10-K filed 2026-03-23.

Source: SEC 10-K, filed 2026-03-23

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