ERBB2 and breast cancer: Unfortunately, despite the clinical efficacy reported in several studies, relevant pharmacoeconomic analyses have failed to confirm the addition of pertuzumab to trastuzumab and docetaxel (THP) as first-line treatments for patients with HER2-positive metastatic BC are cost-effective compared with standard therapy options (trastuzumab and docetaxel, TH) [10,42].