Sac-TMT Sequential Capecitabine Versus Capecitabine in Early-Stage High-Risk Triple-Negative Breast Cancer Without BRCA Mutations

The goal of this clinical trial is to evaluate the efficacy and safety of sacituzumab tirumotecan (sac-TMT) sequential capecitabine versus single-agent capecitabine as adjuvant intensified therapy in patients with high-risk early-stage triple-negative breast cancer (TNBC) without BRCA mutations. The main questions it aims to answer are: 1. Does sacituzumab tirumotecan (sac-TMT) sequential capecitabine improve survival outcomes compared with capecitabine monotherapy in this patient population? 2. What is the safety profile of sacituzumab tirumotecan (sac-TMT)-containing adjuvant therapy versus capecitabine monotherapy? Researchers will compare the sacituzumab tirumotecan (sac-TMT)-sequential-capecitabine experimental arm with the capecitabine-alone control arm to see if the experimental regimen provides superior adjuvant anti-tumor efficacy with acceptable safety. Participants will be randomized in a 1:1 to Receive assigned study treatment as follows: Experimental arm: Sacituzumab tirumotecan (sac-TMT) 4 mg/kg intravenously on Day 1 of each 3-week cycle for 8 cycles, followed by sequential capecitabine at stratified doses; patients with prior PD-1/L1 inhibitor exposure will continue PD-1/L1 inhibitor therapy for up to 1 year Control arm: Capecitabine monotherapy at stratified doses; patients with prior PD-1/L1 inhibitor exposure will continue PD-1/L1 inhibitor therapy for up to 1 year