EO-1022

EO-1022 is a preclinical, site-specifically glycan-conjugated HER3-targeting antibody-drug conjugate developed for HER3-expressing solid tumors. It combines seribantumab, a fully human anti-HER3 IgG2 monoclonal antibody, with the microtubule-disrupting payload monomethyl auristatin E through Synaffix glycan-conjugation, spacer, and linker-payload technologies. The ADC has a homogeneous drug-to-antibody ratio of 4 and showed HER3-dependent cellular internalization, cytotoxicity, and antitumor activity in preclinical breast cancer and EGFR-mutant non-small cell lung cancer models. ([sec.gov](https://www.sec.gov/Archives/edgar/data/1783032/000155837025007806/elev-20250515xex99d1.htm))