- ≤ 3 prior chemotherapies in the metastatic setting. Prior anthracycline, taxane, gemcitabine, and anti-HER2 agents (i.e. trastuzumab, pertuzumab, lapatinib, neratinib, TDM-1, etc.) are allowed. If patients received prior gemcitabine, it could not have been combined with pertuzumab. Patients should have progression of disease on current therapy.