Jiayu Wang, Quchang Ouyang, Weimin Xie, Zhaofeng Niu, Qingyuan Zhang, Xi Yan, Yue'e Teng, Jianying Chang, Ying Cheng, Airong Wang, Jingfen Wang, Herui Yao, Zhuangqing Yang, Tao Sun, Zhongsheng Tong, Xinhong Wu, Yongsheng Wang, Enxiang Zhou, Xiangshun Kong, Xujuan Wang, De Zeng, Shanshan Gu, Yanyan Hou, Dandan Gao, Zerui Qu, Chenran Han, Jianmin Fang, Binghe Xu
Patients with HER2-positive advanced breast cancer with liver metastases (BCLM) have poor prognosis. Study RC48-C006 is a prospective, open-label, multi-center, randomized phase 2/3 trial (ClinicalTrials.gov identifier, NCT03500380). Based on the phase 2 results, the phase 3 stage was initiated to evaluate disitamab vedotin (DV) versus lapatinib plus capecitabine (L + C) in patients with HER2-positive BCLM who were previously treated with trastuzumab and taxanes. The results from the phase 3 stage are reported in this article. A total of 104 patients were randomized at 1:1 to receive DV (53 patients) or L + C (51 patients). Progression-free survival (PFS) assessed by the blinded Independent Review Committee (BIRC) was significantly improved with DV versus with L + C (median: 9.9 vs 4.9 months; stratified hazard ratio [HR]: 0.56 [95.48% CI, 0.35-0.91]; 2-sided P = 0.01), meeting the pre-specified primary endpoint. The investigator-assessed PFS was consistent with the BIRC assessment. Prespecified subgroup analysis of PFS consistently favored DV. Similar incidences of grade ≥3 treatment-related adverse events were reported with DV versus L + C (37.7% vs 36.0%). The present findings support DV as a treatment option for HER2-positive BCLM following trastuzumab and taxane therapy.