Median PFS and OS for HER2/neu-positive breast cancer in patients receiving trastuzumab, pertuzumab, and taxane versus trastuzumab and taxane was 18.5 versus 12.4 months and 56.5 versus 40.8 months, respectively.19,20 In a subset analysis of HER2/neu-positive patients, those who received targeted therapy showed better PFS and OS. This evidence concerns the gene ERBB2 and breast cancer.