【TAIPEI, SHANGHAI, and SAN FRANCISCO, Jul 11, 2025】
HCB303 is a novel fusion protein designed to simultaneously target multiple major immunosuppressive pathways, including PD-L1/PD-1, SIRPα/CD47, and others. By engaging both the innate and adaptive immune systems, HCB303 aims to comprehensively enhance immune activation within the tumor microenvironment. The molecule is engineered for precise targeting of tumor cells expressing, PD-L1, and CD47, leading to T cell activation, natural killer (NK) cell cytotoxicity, and macrophage-mediated phagocytosis.
In in vitro studies, HCB303 exhibited superior binding and blocking capabilities at its intended targets. It outperformed existing antibody therapies across multiple functional assays, including maintaining CD226 (an activating receptor) expression, promoting T cell activation, and enhancing phagocytosis against PD-L1-high tumor cells.
In in vivo animal models, HCB303 demonstrated robust tumor inhibition in both human PBMC/tumor co-mixed xenograft model and hTIGIT/hCD47 transgenic mouse model. Treatment with HCB303 led to increased activation of immune cells and a higher proportion of tumor-infiltrating lymphocytes (TILs), supporting its efficacy through multiple immune-modulatory mechanisms.
Furthermore, preliminary toxicology and pharmacokinetic (PK) studies in cynomolgus monkeys indicate that HCB303 demonstrates good tolerability and predictable PK characteristics, establishing a solid foundation for IND filing and future clinical development.
HCB303 is currently in the process development phase, with an IND submission targeted for completion by 2026. The development of HCB303 represents a new milestone in HanchorBio’s multi-target immunotherapy approach. The company will continue to optimize drug design and expand clinical application potential, hoping to provide breakthrough treatment options for patients with refractory cancers.