The overall aim of the ACTOv trial is to evaluate the efficacy, acceptability, deliverability, compliance, and safety of Adaptive Therapy (AT) with carboplatin, based on changes in CA125, in patients with platinum-sensitive, relapsed high grade serous or high grade endometrioid carcinoma of the ovary, fallopian tube or peritoneum, progressing on or more than 6 months after day 1 of the last cycle of platinum-based chemotherapy.