A gap in the approved solid tumor immunotherapy landscape has widened further with US FDA clearance of an investigational new drug application for HBM7004, a B7H4×CD3 bispecific antibody developed by Harbour BioMed (HKEX: 02142), enabling a first-in-human Phase I trial in patients with advanced solid tumors. No approved therapy currently targets B7H4, and no CD3-bispecific T-cell engager has received regulatory clearance in any solid tumor indication.
B7H4, also known as VTCN1, is a cell-surface protein expressed at low levels in normal tissue but overexpressed across a range of common solid tumors, including breast, ovarian, endometrial, and non-small cell lung cancers. Its expression is largely independent of PD-L1, positioning it as a distinct immune evasion axis that checkpoint inhibitors such as Merck's pembrolizumab (Keytruda) do not directly address. Despite the prevalence of B7H4 overexpression across these tumor types, the target has remained clinically unexploited.
HBM7004 is designed to bridge that gap. As a bispecific antibody, it binds B7H4 on tumor cells and CD3 on T cells simultaneously, physically redirecting cytotoxic T cells to B7H4-expressing cancer cells. The construct was developed using Harbour BioMed's HBICE platform, which builds on the company's heavy-chain-only antibody technology to generate bispecific immune cell engagers. In preclinical studies, HBM7004 demonstrated intratumoral B7H4-dependent T-cell activation, anti-tumor efficacy across multiple animal models, in vivo stability, and what the company described as reduced systemic toxicity relative to systemic immune activation approaches.
The preclinical package also included combination data. When tested alongside a B7H4×4-1BB bispecific antibody at low effector-to-target cell ratios, HBM7004 showed synergistic anti-tumor effects, a finding Harbour BioMed said indicated an encouraging therapeutic window. The 4-1BB co-stimulatory axis has been a subject of broad oncology research interest as a means of amplifying T-cell responses, and the combination signal adds a potential rational basis for future combination strategies.
The Phase I study will evaluate safety, tolerability, pharmacokinetics, and anti-tumor activity of HBM7004 in subjects with advanced solid tumors. No trial registry identifier has been confirmed in publicly available materials at the time of this report. The study design beyond these primary parameters has not been disclosed.