ERBB2 and breast cancer: Another study evaluating trastuzumab plus lapatinib for the treatment of HER2+ BC reported that the observed response rate (ORR) was 50% in the first-line; 57% and 40% of patients in the two cohorts gained clinical benefit; and it showed a higher ORR (in the range of 24%–35%) than that of using trastuzumab or lapatinib alone [89].