HanchorBio Presents Preclinical Data on HCB301 at SITC 2025

TAIPEI, SHANGHAI, and SAN FRANCISCO, Nov. 5, 2025 /PRNewswire/ -- HanchorBio Inc. (TPEx: 7827), a global clinical-stage biotechnology company advancing next-generation immunotherapies for oncology and autoimmune diseases, today announced that the preclinical data on HCB301, a novel tri-specific immunotherapeutic fusion protein, has been accepted for presentation at the 40th Annual Meeting of the Society for Immunotherapy of Cancer (SITC), taking place November 5-9, 2025, in National Harbor, Maryland. Featured in a poster presentation, the data highlight HCB301's differentiated design and multi-pronged antitumor mechanism, which engages both innate and adaptive immunity.

HCB301 is designed to simultaneously:

• Block SIRPα-CD47 interaction to enable macrophage-mediated phagocytosis
• Block PD-1-PD-L1 signaling to restore exhausted T-cell function
• Trap TGFβ to overcome stromal and immune exclusion in tumor microenvironment (TME)

This tripartite approach aims to overcome the limitations of existing checkpoint inhibitors by activating both arms of the immune system, especially in tumors with immunologically 'cold' or suppressive tumor microenvironments (TMEs) resistant to current treatments.

In addition to the HCB301 preclinical poster presented on November 5, HanchorBio will also present two late-breaking abstracts on November 7 to showcase clinical data on its SIRPα-Fc fusion protein HCB101. Together, the three posters underscore the breadth and translational strength of HanchorBio's proprietary Fc-Based Designer Biologics (FBDB™) platform across innate and adaptive immune pathways.

Scott Liu, Ph.D., Founder, Chairman, and CEO of HanchorBio, commented: "HCB301 builds directly on the foundation of HCB101, our clinical-stage SIRPα-engineered fusion protein. By integrating PD-1 blockade and TGFβ neutralization into a single molecule, HCB301 represents what we believe to be the first-in-class tri-specific fusion protein that simultaneously targets immune checkpoints, immune suppression, and macrophage dysfunction. This design reflects our commitment to building modular, next-generation immunotherapies with global translation potential. With IND clearance and first-patient dosing now achieved in both the US and China, HCB301 demonstrates the scalability of our FBDB™ platform and the executional readiness of our team across regions. As we advance HCB301 into the clinical stage, this milestone further positions HanchorBio as a long-term innovation partner for global co-development, particularly in cancers with high resistance to conventional immunotherapies."

Preclinical highlights of HCB301 (SITC Poster #P321)
Title: HCB301, a tri-specific fusion protein targeting SIRPα/CD47, PD-1/PD-L1, and TGFβ, promotes anti-tumor macrophage and T cell activity in preclinical models of solid tumors

• Strong immune activation: HCB301 induced robust antibody-dependent cellular phagocytosis (ADCP), activated tumor-associated macrophages, and increased CD8+ T cell infiltration.
• Synergistic antitumor efficacy: In CT26, MC38, and B16F10 models, HCB301 demonstrated superior tumor growth inhibition compared with single- or dual-arm comparators.
• TGFβ suppression: HCB301 potently neutralized active TGFβ, reversing TME immunosuppression, and restoring T cell function.
• Fc-effector tuning: Selective Fc engineering optimized immune activation while minimizing off-target toxicity.

"HCB301 was purpose-built to break through the resistance barriers that limit current PD-1 or CD47 monotherapies," remarked Wenwu Zhai, Ph.D., Chief Scientific Officer of HanchorBio. "Each of its three arms addresses a key axis of tumor immune evasion: CD47 for innate immune clearance, PD-1 for adaptive immune reactivation, and TGFβ for TME remodeling. Our preclinical data show that HCB301 delivers synergistic immune activation and tumor control, strongly supporting its advancement into the clinic."

For more information, please visit: https://www.HanchorBio.com