HCB301 is a first-in-class tri-specific immunotherapy targeting SIRPα-CD47, PD-1/PD–L1, and TGFβ; it shows potent macrophage activation, T-cell restoration, and tumor microenvironment remodeling in preclinical solid tumor models.
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.”
About HCB301
Based on company analysis, HCB301 is the first clinical-stage tri-specific recombinant Fc-fusion protein that simultaneously targets SIRPα/CD47, PD-1/PD-L1, and TGFβ. It was designed using HanchorBio’s FBDB™ platform, which enables modular multi-arm immunotherapies with tunable Fc regions and enhanced manufacturability.
HCB301 integrates:
- A high-affinity SIRPα domain that binds cancer cells’ CD47 to promote macrophage phagocytosis
- A PD-1 extracellular domain that blocks PD-L1 and restores T-cell effector function
- A TGFβRII domain that traps active TGFβ to alleviate immunosuppressive signals in the tumor microenvironment
The protein shows a favorable safety profile in repeat-dose toxicology studies in cynomolgus monkeys. Its differential tumor vs. RBC binding profile may reduce the risk of anemia, thrombocytopenia, or other cytopenia while maintaining potent anti-tumor activity.
HCB301 achieved IND clearance and first-patient dosing in both the US and China in 2025. The ongoing Phase 1 study (HCB301-101; NCT06487624) is a multi-regional, multi-center, open-label, dose-finding, first-in-human trial evaluating the safety, tolerability, pharmacokinetics (PK), pharmacodynamics (PD), and preliminary clinical efficacy of HCB301 in patients with advanced solid tumors or relapsed and refractory classical Hodgkin lymphoma.
About HanchorBio
Based in Taipei, Shanghai, and the San Francisco Bay Area, HanchorBio (TPEx: 7827) is a global biotechnology company specializing in immuno-oncology. It is led by an experienced team of pharmaceutical industry veterans with a proven track record in biologics discovery and international development, aiming to rewrite the landscape of cancer therapies. Committed to reactivating the immune system to fight diseases, the company’s proprietary Fc-Based Designer Biologics (FBDB™) platform enables the development of unique biologics with diverse multi-targeting modalities, unleashing both innate and adaptive immunity to overcome the current challenges of anti-PD1/L1 therapies. The FBDB™ platform has successfully delivered proof-of-concept data in several in vivo tumor animal models. By making breakthroughs in multi-functional innovative molecular configurations in R&D and improving the manufacturing process in CMC, HanchorBio develops transformative medicines to address unmet medical needs. For more information, please visit: https://www.HanchorBio.com
HanchorBio–Leading the Next Wave of lmmuno-Oncology at SITC2025
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