The average DAR achieved was 4.0 and 3.4 for A5/158-vc-MMAE and Isotype-vc-MMAE, respectively, comparable with the average DAR of 3.5 of the ADC Trastuzumab-DM1, which is approved for the treatment of HER2-positive breast cancers. The gene discussed is ERBB2; the disease is breast cancer.