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| Title | B7-H3-mediated cis-inhibition of EGFR by a tumor-selective bispecific antibody enhances anti-tumor efficacy and minimizes toxicities. |
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| Journal, issue, pages | Nat Commun, Vol. 17, Issue 1, Year 2026 |
| Publish date | Feb 24, 2026 |
Authors | Jian Guan / Tiongsun Chia / Bin Li / Tianyu Zhu / Zhengguang Liao / Junjie Deng / Fenggen Fu / Weiwei Wu / Chengtao Liu / Ya Liu / Ninghuan Li / Lili Yue / Lei Cao / Jia Lu / Mengjia Zhu / Xiaomin Ling / Huilin Zheng / Shuming Lin / Li Li / Shuaixiang Zhou / Kaijie He / ![]() |
| PubMed Abstract | Therapeutic targeting of epidermal growth factor receptor (EGFR) in solid tumors faces significant limitations due to on-target/off-tumor toxicities, underscoring the urgent need for tumor-selective ...Therapeutic targeting of epidermal growth factor receptor (EGFR) in solid tumors faces significant limitations due to on-target/off-tumor toxicities, underscoring the urgent need for tumor-selective anti-EGFR therapies. Comprehensive bioinformatics and histopathological analyses identify marked upregulation of B7-H3 across EGFR-positive malignancies, contrasting with its minimal expression in healthy tissues. Leveraging an unbiased functional screen of bispecific antibodies (bsAbs) combining diverse B7-H3 and EGFR binders, we develop IBI334, a EGFR/B7-H3 bsAb exhibiting exceptional tumor selectivity. In preclinical models, IBI334 outperforms conventional EGFR antibodies by demonstrating superior EGFR occupancy, enhanced ligand-blocking efficacy, accelerated receptor degradation, and potent suppression of downstream EGFR signaling. Mechanistic studies demonstrate B7-H3-mediated cis-inhibition. The human B7-H3 extracellular domain (ECD) in complex with anti-B7-H3 Fab is resolved by cryo-EM, revealing critical residues for the antibody-B7-H3 interaction. IBI334 demonstrates robust antitumor activity in vitro and in vivo across EGFR-driven tumor models and synergized effectively with KRAS inhibitors. Toxicological evaluations in non-human primates reveals a favorable safety profile, with no EGFR-related adverse effects observed at doses up to 120 mg/kg over 4 weeks. Supported by these preclinical findings, IBI334 has advanced to a phase 1 clinical trial (NCT05774873) for advanced/metastatic solid tumors. |
External links | Nat Commun / PubMed:41735305 / PubMed Central |
| Methods | EM (single particle) |
| Resolution | 2.98 - 3.67 Å |
| Structure data | EMDB-63503, PDB-9ly5: EMDB-63505, PDB-9ly6: |
| Source |
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Keywords | ANTITUMOR PROTEIN/IMMUNE SYSTEM / B7-H3 / antibody / complex / ANTITUMOR PROTEIN-IMMUNE SYSTEM complex |
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homo sapiens (human)
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