STRO-004

STRO-004 is a next-generation antibody-drug conjugate (ADC) developed by Sutro Biopharma. It targets tissue factor (TF), a protein highly expressed in various solid tumors, using a high-affinity, internalizing IgG1 monoclonal antibody. The ADC is site-specifically conjugated with an exatecan payload—a potent topoisomerase I inhibitor—via an optimized β-glucuronidase-cleavable linker designed for stability in circulation and tumor-selective payload release. This design aims to maximize anti-tumor efficacy while minimizing off-target toxicities such as bleeding and skin/eye toxicity commonly associated with tissue factor targeting. Preclinical studies have demonstrated potent, dose-dependent anti-tumor activity across multiple cancer models (including head and neck, cervical, pancreatic, non-small cell lung cancer) and a favorable safety profile at all tested doses[1][3][5][6][8]. Sutro’s proprietary cell-free XpressCF+ platform enables precise site-specific conjugation for homogeneous drug-antibody ratios (DAR), supporting higher potency and improved pharmacokinetics[3]. As of mid-2025, STRO-004 remains in preclinical development with plans to enter clinical trials in the second half of 2025[6][7].