ERBB2 and breast cancer: A phase 1 first-in-human study, C001 CANCER NCT02881138, and a phase 1b open-label dose-escalation trial, C003 cancer NCT03052634, in patients with HER2-positive metastatic breast cancer showed that patients in both the studies had locally advanced or metastatic HER2-positive breast cancer with IHC 3 or IHC 2-positive with FISH amplification.