STRO-00Y

STRO-00Y is a preclinical-stage dual-payload antibody-drug conjugate (ADC) being developed by Sutro Biopharma for the treatment of solid tumors. The asset is engineered using Sutro's proprietary cell-free protein synthesis platform, **XpressCF**, which allows for the site-specific conjugation of multiple distinct payloads to a single antibody. This dual-payload architecture is designed to deliver two different therapeutic mechanisms of action directly to tumor cells, potentially enhancing efficacy and overcoming resistance mechanisms that limit single-payload ADCs. As of mid-2026, the specific molecular target and the identities of the cytotoxic or immunomodulatory payloads remain undisclosed by the sponsor.