STX-721, a Covalent EGFR/HER2 Exon 20 Inhibitor, Utilizes Exon 20–Mutant Dynamic Protein States and Achieves Unique Mutant Selectivity Across Human Cancer Models

These data highlight that STX-721 shows a high level of mutant EGFR selectivity across human preclinical cancer models and may provide an improved clinical efficacy versus adverse event profile relative to existing drugs.