As well as trastuzumab emtansine, which uses DM1 as its cytotoxic payload and has been approved for the treatment of HER2-positive breast cancer, a number of maytansinoid-conjugated ADCs are under clinical evaluation, including naratuximab emtansine (Debio 1562, an anti-CD37 ADC with DM1, phase 2; NCT02564744), mirvetuximab soravtansine (an anti-FOLR1 ADC with DM4, phase 3; NCT02631876), and anetumab ravtansine (an anti-mesothelin ADC with DM4, phase 2; NCT03455556, NCT03126630, NCT03926143, NCT03023722, NCT03587311). This evidence concerns the gene ERBB2 and breast carcinoma.