K-679

**K-679** is Kowa's preclinical epidermal growth factor receptor-targeted antibody drug-loaded unimicelle conjugate designed for EGFR-expressing solid tumors. It combines an anti-EGFR antibody reported to be cetuximab with single-chain polymer-derived unimicelles carrying the microtubule inhibitor DM1 at an ultra-high drug-to-antibody ratio. Following EGFR-mediated tumor-cell binding and internalization, K-679 delivers DM1 intracellularly to inhibit tubulin polymerization, causing mitotic arrest and apoptosis. In xenograft and patient-derived colorectal cancer models, it has shown tumor-selective payload exposure, broad intratumoral distribution, activity in EGFR-low or heterogeneous tumors, and antitumor activity after prior trastuzumab deruxtecan exposure. ([kowa.co.jp](https://www.kowa.co.jp/news/2026/press260406.pdf))