<p>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.</p>

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B7-H3-mediated cis-inhibition of EGFR by a tumor-selective bispecific antibody enhances anti-tumor efficacy and minimizes toxicities

  • 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

摘要

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.