Abstract YO7
Case summary
A 45-year-old woman diagnosed with triple-negative breast cancer (TNBC) and lymph node metastasis in August 2021. Neoadjuvant chemotherapy with paclitaxel, doxorubicin, and cyclophosphamide from August to October 2021 demonstrated initial stable disease (SD), followed by progressive disease (PD) after albumin-bound paclitaxel and carboplatin (November 2021-January 2022), and vinorelbine and carboplatin (February-April 2022).Progressive disease occurred after two cycles of each treatment regimen.Post-mastectomy genomic profiling showed wild-type germline BRCA1/2 and a high score for homologous recombination deficiency (HRD).
Despite various treatments, including targeted therapy and immunotherapy, the patient experienced recurrent disease and lung metastases. In May 2023, she enrolled in an Investigator-Initiated Clinical Trial (NCT05085626), receiving fluzoparib and chidamide, which ultimately led to progressive disease.
The introduction of sacituzumab govitecan from July 14, 2023, marked a significant therapeutic response, achieving an 8-month partial response (PR) with a remarkable 90% tumor regression observed at 4 months. The adverse events were mild, including grade 1 nausea and grade 2 leukopenia. However, liver metastases identified in March 2024 and subsequent treatment with trastuzumab deruxtecan resulted in progressive disease after two cycles.
This patient presents a case of refractory triple-negative breast cancer that showed rapid progression after various chemotherapy, targeted therapy, and immunotherapy treatments. This case exemplifies the complexities in managing refractory TNBC, particularly when sacituzumab govitecan provides an 8-month period of disease control in a heavily pretreated patient. As an ADC with a topoisomerase I inhibitor payload, the activity of sacituzumab govitecan in this setting underscores the potential for personalized medicine approaches in HRD-positive and BRCA1/2 wild-type germline mTNBC. Future studies are warranted to elucidate biomarker-driven treatment strategies and to expand the evidence base for sacituzumab govitecan in this patient population.