This is a clinical study that has three parts. It is testing a potential new medicine called Sofetabart Mipitecan (Sofe-M) for people with certain types of ovarian, peritoneal, and fallopian tube cancers. Part A enrolls participants with platinum-resistant cancer, meaning their disease progressed during or within six months of platinum-based chemotherapy. Parts B and C enroll participants with platinum-sensitive cancer, whose disease responded and remained controlled for at least six months after completing platinum treatment. The researchers want to find out if Sofe-M works better than the standard treatments that doctors use now and to better understand how safe it is. Each participant's time in the study will depend on how they respond to the treatment.