ERBB2 and metastatic neoplasm: Pmab is a monoclonal antibody that binds to HER2 on extracellular domain II, a different-domain trastuzumab.[4] In the CLEOPATRA trial, superior progression-free survival (PFS) and overall survival (OS) was achieved by adding Pmab to Tmab and docetaxel therapy for patients with HER2-positive MBC who had not received anti-HER2 therapy or chemotherapy for metastatic disease.[5,6] Therefore, this trial is considered a landmark trial that changed the field of clinical practice.