In the phase 1 dose escalation, pts (aged ≥18 y; metastatic EGFRm NSCLC; ECOG PS 0–1; treated with ≥1 EGFR TKI) received BLU-945 mono starting at 25 mg Q. Pts progressing on OSI could receive BLU-945 with 80 mg OSI starting at 50% of the highest safe BLU-945 mono dose....BLU-945 mono and combo with OSI were generally well tolerated and showed robust on-target EGFR ctDNA reduction, with tumor shrinkage in genomically heterogeneous, heavily pretreated pts.