Sequencing SG vs. T-DXd in HER2-Low/TROP2-High Metastatic Breast Cancer

Currently, no phase III RCT has directly compared SG and T-DXd sequencing strategies, and the predictive role of biomarkers remains unclear. Additionally, there is no standard scoring system for Trop-2 expression. The ASCENT trial utilized an H-score method (H-score = 3×%IHC3+ + 2×%IHC2+ + 1×%IHC1+), with scores \<100, 100-200, and \>200 defining low, medium, and high Trop-2 expression, respectively.This prospective study aims to: 1) Evaluate the efficacy of SG vs. T-DXd in HER2-low/Trop-2-high metastatic breast cancer, prioritizing SG for Trop-2-high patients and T-DXd for others. 2) Compare sequential treatment outcomes-T-DXd after SG failure versus SG after T-DXd failure-to inform ADC sequencing in HER2-low disease. Up to one intervening therapy is allowed before sequencing. 3) Identify biomarkers of ADC efficacy and resistance through quantitative protein analysis to optimize patient selection.

NCT Number	NCT07368543
Lead Sponsor	Fudan University
Conditions	Metastatic Breast Cancer
Enrollment	216 participants
Start Date	2026-01-16
Primary Completion	2027-06-01 (estimated)
Study Completion	2028-12-01 (estimated)
Updated on ClinicalTrials.gov	2026-01-28