Izalontamab brengitecan — Investigational Agent

Antibody-Drug Conjugate · Phase 3 · SystImmune / Sichuan Biokin (Baili)

Mechanism of Action

Izalontamab brengitecan is a first-in-class bispecific antibody-drug conjugate targeting both EGFR and HER3, conjugated to a topoisomerase I inhibitor payload via a cleavable linker. Dual targeting of EGFR and HER3 enhances tumor selectivity and internalization while addressing receptor heterogeneity and resistance driven by HER3 upregulation. After internalization, the payload is released to induce DNA damage, apoptosis, and a bystander effect on neighboring tumor cells. The bispecific design aims to broaden activity across EGFR/HER3-expressing epithelial tumors including breast cancer.

Investigational Indications

• Triple-negative breast cancer
• HR+/HER2- breast cancer
• EGFR/HER3-expressing gynecologic and solid tumors
• Non-small cell lung cancer

Key Trials