HanchorBio Files U.S. IND for Second Trispecific Immunotherapy, HCB303
HCB303 integrates SIRPα/CD47, PD-L1/PD-1, and TIGIT/PVR biology to coordinate macrophage, T-cell and NK-cell immunity within a single FBDB™ therapeutic architecture
TAIPEI, SHANGHAI, and SAN FRANCISCO — September 3, 2026 — HanchorBio, Inc. (TWSE: 7827), a global clinical-stage biotechnology company developing next-generation immunotherapies for oncology and immune-mediated diseases, today announced that its wholly owned subsidiary, FBD Biologics Limited, has submitted an Investigational New Drug (IND) application to the U.S. Food and Drug Administration (FDA) for HCB303. Developed using HanchorBio’s proprietary FBDB™ platform, HCB303 is the Company’s second trispecific immunotherapy program to reach clinical development.
HCB303 is a humanized trispecific fusion protein designed to simultaneously target SIRPα/CD47, PD-L1/PD-1, and TIGIT/PVR pathways. By engaging three distinct pathways in a single engineered molecule, HCB303 coordinates macrophage-mediated phagocytosis, T-cell immunity, and NK-cell antitumor activity to counter complex tumor immune resistance.
“HCB303 demonstrates that the FBDB™ platform can reliably generate differentiated therapeutic architectures to address interconnected immune biology,” said Scott Liu, PhD, Founder, Chairman, and CEO of HanchorBio. “Rather than increasing complexity for its own sake, our strategy targets biologically connected resistance mechanisms within single, multi-targeted molecules. HCB301 and HCB303 demonstrate that this is a repeatable platform strategy—not a one-molecule experiment. This is exactly the type of differentiated asset we built the FBDB™ platform to generate, and we believe HCB303 represents a key component of our global oncology pipeline.”
The submission follows pre-IND written feedback received from the FDA in early August 2026. HanchorBio incorporated the Agency’s recommendations—including a dose-limiting toxicity framework, safety monitoring, clinical pharmacology, and a dosage-optimization strategy aligned with the FDA’s Project Optimus principles—into the final IND package.
The planned Phase 1 first-in-human study will evaluate HCB303 in adults with advanced, relapsed, or refractory solid tumors with no remaining standard treatment options. The study will assess safety, tolerability, pharmacokinetics, pharmacodynamics, immunogenicity, biomarkers, and preliminary antitumor activity, incorporating limited accelerated escalation using a Bayesian Optimal Interval (BOIN) dose-escalation design.
“Moving from the pre-IND feedback to full IND submission within weeks highlights our disciplined execution across regulatory, CMC, non-clinical pharmacology, and clinical strategy,” added Alvin Luk, PhD, MBA, President and CMO (Group) & CEO (USA) of HanchorBio. “We look forward to advancing HCB303 into the clinic to evaluate its potential for patients with high unmet needs.”
About HCB303
HCB303 is an investigational, humanized trispecific fusion protein developed via the proprietary FBDB™ platform. Designed to simultaneously modulate the SIRPα/CD47, PD-L1/PD-1, and TIGIT/PVR immune pathways, HCB303 engages innate and adaptive antitumor immunity within a single engineered architecture.
About HanchorBio
HanchorBio (TWSE: 7827) is a global clinical-stage biotechnology company focused on inventing and developing next-generation biologics for cancer and immune-mediated diseases using its proprietary FBDB™ platform.
HanchorBio’s pipeline includes HCB101, its lead SIRPα-based innate immune checkpoint program; HCB301, a clinical-stage trispecific immunotherapy targeting SIRPα, PD-L1, and TGF-β biology; HCB303, a next-generation trispecific program integrating SIRPα, PD-L1, and TIGIT/PVR biology; and additional programs across oncology and immune-mediated diseases. For more information, please visit HanchorBio.com.
Forward-Looking Statements
This press release contains forward-looking statements, including statements regarding the development of HCB303, the timing and potential submission of an IND, initiation and design of future clinical studies, potential therapeutic characteristics and mechanisms of HCB303, development of HanchorBio’s pipeline, and the capabilities and potential of the FBDB™ platform. These statements are based on current expectations and assumptions and involve risks and uncertainties that could cause actual results to differ materially from those described. Regulatory feedback does not constitute approval of an IND or assurance that clinical development will proceed as planned. HanchorBio undertakes no obligation to update forward-looking statements except as required by applicable law.