This study is a multicenter randomized phase 2 trial using a multi-arm design with Bayesian adaptive randomization and efficacy monitoring. Eligible patients have advanced HER2-negative breast cancer...Among the five treatment cohorts, the VEX cohort and the cisplatin cohort had the highest DCR, 69.7% (95% CI 51.7–85.9%) and 73.7% (95% CI 56.1–88.7%), respectively….