Taipei, Shanghai and San Francisco – October 05, 2026 -- HanchorBio, Inc. (TWSE: 7827) said the U.S. Food and Drug Administration has cleared the investigational new drug application for HCB303, clearing the path for the company's second trispecific immunotherapy to enter human testing.

FDA clearance unlocks Phase 1 trial for advanced solid tumors

The clearance allows HanchorBio to launch a Phase 1 first-in-human, dose-escalation, multi-regional study (HCB303-ONC-101) in patients with advanced, relapsed or refractory solid tumors who have exhausted standard treatment options. The trial will assess safety, tolerability, pharmacokinetics, pharmacodynamics, immunogenicity, biomarkers and preliminary antitumor activity. The decision follows pre-IND feedback HanchorBio received from the FDA in August 2026.

HCB303 targets three immune pathways through a single engineered molecule

Built on HanchorBio's proprietary FBDB platform, HCB303 is a humanized trispecific fusion protein engineered to act simultaneously on the TIGIT/PVR, PD-L1/PD-1 and SIRPα/CD47 pathways. Rather than directly blocking the TIGIT receptor like conventional antibodies, HCB303 uses a TIGIT-Fc ligand-trap strategy to intercept TIGIT ligands PVR/CD155 and CD112, a design intended to reduce TIGIT-mediated inhibitory signaling while preserving CD226-driven activation of T cells and NK cells. The molecule adds PD-L1 blockade and SIRPα-mediated enhancement of macrophage phagocytosis, aiming to coordinate innate and adaptive antitumor immune responses within the tumor microenvironment.

Scott Liu, PhD, Founder and Chairman of HanchorBio, said blocking PVR signaling through a standard anti-TIGIT antibody releases the inhibitory signal but fails to address CD226 down-regulation needed for stronger T- and NK-cell activation. He said HCB303 was engineered to go further by intercepting TIGIT ligands while preserving the CD226 activating axis and simultaneously blocking PD-L1 and CD47.

Second trispecific candidate advances HanchorBio's broader clinical pipeline

Alvin Luk, PhD, MBA, President and CMO (Group) & CEO (USA) of HanchorBio, said the FDA clearance moves HCB303 from a biological hypothesis into clinical testing, with the company's near-term focus on whether its TIGIT biology and dual innate-adaptive immune engagement translate into clinical benefit. HCB303 joins HCB301, a clinical-stage trispecific immunotherapy targeting SIRPα, PD-L1 and TGF-β biology, as the company's second multispecific program to reach the clinic under the FBDB platform.