DF203

DF203 is a bispecific antibody candidate developed by Suzhou Dingfu Target Biotechnology for the treatment of advanced solid tumors. It is designed to simultaneously target Programmed Death-Ligand 1 (PD-L1) and 4-1BB (CD137). By binding to PD-L1 on tumor cells, DF203 blocks the inhibitory PD-1/PD-L1 signaling pathway, which is a common mechanism of tumor immune evasion. Concurrently, the molecule provides a localized co-stimulatory signal through 4-1BB to tumor-infiltrating T cells. This dual mechanism is intended to enhance anti-tumor immune responses while minimizing the systemic toxicities, such as hepatotoxicity, that have historically been associated with non-targeted 4-1BB agonists. The drug is currently being evaluated in Phase 1 clinical trials to assess its safety, tolerability, and preliminary efficacy in patients with advanced malignancies.