ERBB2 and breast cancer: For instance, a Taiwanese cost-effectiveness analysis showed that a trastuzumab biosimilar (not explicitly named in the study) combined with docetaxel was a cost-effective alternative to the reference trastuzumab in metastatic HER2-positive breast cancer, reporting an incremental cost-effectiveness ratio of NTD 811,050 (~USD $28,966) per quality-adjusted life year (QALY) gained (25).