312P Efficacy of sequential antibody-drug conjugates (ADCs) targeting topoisomerase-1 in HER2-low metastatic breast cancer (MBC): Updated results and additional analyses from the French multicenter retrospective ADC-low cohort

Sequential use of ADCs targeting topoisomerase-1 is the current treatment recommendation for pts with HER2-low MBC. However, the efficacy of subsequent ADC treatment and the best sequence remain unknown. We previously reported at SABCS 2023 and recently published (BJC 2024) a poor progression-free survival (PFS2) with a second ADC in a French retrospective study of heavily pretreated patients (ADC-Low).