Successful Sequential Use of the Antibody-Drug Conjugate Trastuzumab Deruxtecan After Progression on Sacituzumab Govitecan in a Recurrent Treatment-Resistant Ovarian Cancer Patient: A Case Report.

Treatment of recurrent, platinum-resistant, high-grade serous ovarian cancer (HGSOC) remains a challenge. Novel treatment options based on antibody-drug conjugates (ADCs) are currently in clinical trials in platinum-resistant and recurrent ovarian cancer patients. Optimizing the sequential use of ADCs is an area of unmet need and of rising clinical importance. A 70-year-old with recurrent, metastatic, platinum-resistant HGSOC overexpressing TROP2 and HER2 experienced a significant response to the ADC trastuzumab deruxtecan (anti-HER2) after progression on sacituzumab govitecan (anti-TROP2). Following trastuzumab deruxtecan treatment, she experienced a remarkable and prolonged (i.e., over six months) clinical response with resolution of liver metastatic lesions and a decrease in the size of abdominal tumor masses, along with a decrease in CA-125. She has now completed eight cycles (i.e., over six months of treatment), and her disease continues to demonstrate a prolonged response to trastuzumab deruxtecan treatment. The ADC has been well tolerated at a dose of 5.4 mg/kg with no dose-limiting toxicity or need for dose reductions. HGSOC patients with chemotherapy and sacituzumab govitecan-resistant disease may experience durable responses with the sequential use of trastuzumab deruxtecan. ADCs with a similar cytotoxic payload but targeting a different antigen may represent effective treatment options in patients with HGSOC.