BH4601

BH4601 is a novel tetravalent bispecific antibody-drug conjugate (ADC) that simultaneously targets Programmed death-ligand 1 (PD-L1) and B7-H3 (CD276). Developed by Beijing Hanmi Pharmaceutical and FDC Biotech, the molecule consists of a bispecific antibody conjugated to XYD-295, a topoisomerase I inhibitor payload. This dual-targeting strategy is designed to address the compensatory upregulation often observed between PD-L1 and B7-H3 in various malignancies, thereby broadening tumor targeting and alleviating T-cell suppression. Preclinical data presented at AACR 2026 demonstrated that BH4601 exhibits potent PD-1/PD-L1 blockade, efficient internalization, and significant tumor control in multiple in vivo models of solid tumors, while maintaining a well-tolerated safety profile.