While the cited prior art discloses using anti-CDH6 ADCs to treat various types of cancer (including ovarian cancer, generally), none of the references include these recited subpopulations of patients. Treating these particular subpopulations is novel and inventive because there is nothing in the cited references that would have led a person skilled in the art to believe the claimed ADC could be used in these populations. Further, Example 1 demonstrates the surprisingly beneficial therapeutic effect of the ADC against resistant/recurrent/pretreated ovarian cancer regarding platinum-based chemotherapy (Carboplatin and Paclitaxel).