AUTHOR=Duan Yangyang , Sun Tao , Chen Zhanhong , Ouyang Quchang , Li Kai , Yan Min , Lv Zheng , Li Zhaohui , Man Li , Luo Xu , Dong Yuyang , Jing Mingxi , Wang Yan , Guo Xiangyu , Xu Junnan , Li Xiaorui , Jiang Cui , E Ying , Jiang Lei , Cao Hui , Jia Yufeng , Wu Jie , Li Huan , Zhang Liang , Jiang Yujun , Gao Zhichao , Dong Fangyuan 

TITLE=Real-world efficacy and safety of inetetamab-based therapy in HER2-positive metastatic breast cancer patients with prior exposure to trastuzumab

JOURNAL=Frontiers in Oncology

VOLUME=Volume 15 - 2025

YEAR=2025

URL=https://www.frontiersin.org/journals/oncology/articles/10.3389/fonc.2025.1496371

DOI=10.3389/fonc.2025.1496371

ISSN=2234-943X

ABSTRACT=BackgroundUntil now there has been no comprehensive data from extensive samples to evaluate the therapeutic potential of inetetamab in metastatic breast cancer (MBC) patients who had a history of trastuzumab treatment. Some previous studies had either small sample sizes from single-center, or partial enrolled patients without prior exposure to trastuzumab. This study aimed to provide a deep analysis of inetetamab-based therapy in this specific population.MethodsA multicenter retrospective study collected clinicopathological data from a total of 500 patients between Jul 2020 and Oct 2023. Progression-free survival (PFS) was estimated as the primary endpoint. Secondary endpoints included objective response rate (ORR), disease control rate (DCR) and adverse events (AEs). The association of risk factors with the effect of inetetamab treatment on PFS was evaluated using Cox proportional hazards regression analysis.ResultsIn the overall cohort, we observed a median PFS of 8.0 months, an ORR of 28.6% and a DCR of 89.2% (median treatment line: third line). Meanwhile, patients who received a combination treatment regime of inetetamab + tyrosine kinase inhibitors (TKIs) + chemotherapy achieved the most prolonged PFS of 9.0 months and the higher ORR of 29.3%. Ki67 index, distant lymph nodes metastasis and treatment strategy were independent predictors of PFS. The most common all-grade AEs were neutropenia (182/500, 36.4%) and leukopenia (157/500, 31.4%).ConclusionsInetetamab was promising in HER2-positive MBC patients who had prior exposure to trastuzumab, offering a new option for patients with a prior failure of trastuzumab.